Commit 9362f382ab

Andrew Kelley <andrew@ziglang.org>
2021-01-02 20:32:30
stage2: implement function call inlining in the frontend
* remove the -Ddump-zir thing. that's handled through --verbose-ir * rework Fn to have an is_inline flag without requiring any more memory on the heap per function. * implement a rough first version of dumping typed zir (tzir) which is a lot more helpful for debugging than what we had before. We don't have a way to parse it though. * keep track of whether the inline-ness of a function changes because if it does we have to go update callsites. * add compile error for inline and export used together. inline function calls and comptime function calls are implemented the same way. A block instruction is set up to capture the result, and then a scope is set up that has a flag for is_comptime and some state if the scope is being inlined. when analyzing `ret` instructions, zig looks for inlining state in the scope, and if found, treats `ret` as a `break` instruction instead, with the target block being the one set up at the inline callsite. Follow-up items: * Complete out the debug TZIR dumping code. * Don't redundantly generate ZIR for each inline/comptime function call. Instead we should add a new state enum tag to Fn. * comptime and inlining branch quotas. * Add more test cases.
1 parent fea8659
src/codegen/c.zig
@@ -275,7 +275,7 @@ pub fn generate(file: *C, module: *Module, decl: *Decl) !void {
         try writer.writeAll(" {");
 
         const func: *Module.Fn = func_payload.data;
-        const instructions = func.analysis.success.instructions;
+        const instructions = func.data.body.instructions;
         if (instructions.len > 0) {
             try writer.writeAll("\n");
             for (instructions) |inst| {
src/codegen/wasm.zig
@@ -63,7 +63,7 @@ pub fn genCode(buf: *ArrayList(u8), decl: *Decl) !void {
     // TODO: check for and handle death of instructions
     const tv = decl.typed_value.most_recent.typed_value;
     const mod_fn = tv.val.castTag(.function).?.data;
-    for (mod_fn.analysis.success.instructions) |inst| try genInst(buf, decl, inst);
+    for (mod_fn.data.body.instructions) |inst| try genInst(buf, decl, inst);
 
     // Write 'end' opcode
     try writer.writeByte(0x0B);
src/link/MachO/DebugSymbols.zig
@@ -936,16 +936,6 @@ pub fn initDeclDebugBuffers(
     const typed_value = decl.typed_value.most_recent.typed_value;
     switch (typed_value.ty.zigTypeTag()) {
         .Fn => {
-            const zir_dumps = if (std.builtin.is_test) &[0][]const u8{} else build_options.zir_dumps;
-            if (zir_dumps.len != 0) {
-                for (zir_dumps) |fn_name| {
-                    if (mem.eql(u8, mem.spanZ(decl.name), fn_name)) {
-                        std.debug.print("\n{}\n", .{decl.name});
-                        typed_value.val.cast(Value.Payload.Function).?.func.dump(module.*);
-                    }
-                }
-            }
-
             // For functions we need to add a prologue to the debug line program.
             try dbg_line_buffer.ensureCapacity(26);
 
src/link/Elf.zig
@@ -2178,16 +2178,6 @@ pub fn updateDecl(self: *Elf, module: *Module, decl: *Module.Decl) !void {
         else => false,
     };
     if (is_fn) {
-        const zir_dumps = if (std.builtin.is_test) &[0][]const u8{} else build_options.zir_dumps;
-        if (zir_dumps.len != 0) {
-            for (zir_dumps) |fn_name| {
-                if (mem.eql(u8, mem.spanZ(decl.name), fn_name)) {
-                    std.debug.print("\n{s}\n", .{decl.name});
-                    typed_value.val.castTag(.function).?.data.dump(module.*);
-                }
-            }
-        }
-
         // For functions we need to add a prologue to the debug line program.
         try dbg_line_buffer.ensureCapacity(26);
 
src/codegen.zig
@@ -532,7 +532,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         self.code.items.len += 4;
 
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
 
                         const stack_end = self.max_end_stack;
                         if (stack_end > math.maxInt(i32))
@@ -576,7 +576,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         });
                     } else {
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
                         try self.dbgSetEpilogueBegin();
                     }
                 },
@@ -593,7 +593,7 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
 
                         try self.dbgSetPrologueEnd();
 
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
 
                         // Backpatch stack offset
                         const stack_end = self.max_end_stack;
@@ -638,13 +638,13 @@ fn Function(comptime arch: std.Target.Cpu.Arch) type {
                         writeInt(u32, try self.code.addManyAsArray(4), Instruction.pop(.al, .{ .fp, .pc }).toU32());
                     } else {
                         try self.dbgSetPrologueEnd();
-                        try self.genBody(self.mod_fn.analysis.success);
+                        try self.genBody(self.mod_fn.data.body);
                         try self.dbgSetEpilogueBegin();
                     }
                 },
                 else => {
                     try self.dbgSetPrologueEnd();
-                    try self.genBody(self.mod_fn.analysis.success);
+                    try self.genBody(self.mod_fn.data.body);
                     try self.dbgSetEpilogueBegin();
                 },
             }
src/Compilation.zig
@@ -1459,10 +1459,10 @@ pub fn performAllTheWork(self: *Compilation) error{ TimerUnsupported, OutOfMemor
                 const module = self.bin_file.options.module.?;
                 if (decl.typed_value.most_recent.typed_value.val.castTag(.function)) |payload| {
                     const func = payload.data;
-                    switch (func.analysis) {
+                    switch (func.bits.state) {
                         .queued => module.analyzeFnBody(decl, func) catch |err| switch (err) {
                             error.AnalysisFail => {
-                                assert(func.analysis != .in_progress);
+                                assert(func.bits.state != .in_progress);
                                 continue;
                             },
                             error.OutOfMemory => return error.OutOfMemory,
@@ -1471,12 +1471,16 @@ pub fn performAllTheWork(self: *Compilation) error{ TimerUnsupported, OutOfMemor
                         .sema_failure, .dependency_failure => continue,
                         .success => {},
                     }
-                    // Here we tack on additional allocations to the Decl's arena. The allocations are
-                    // lifetime annotations in the ZIR.
+                    // Here we tack on additional allocations to the Decl's arena. The allocations
+                    // are lifetime annotations in the ZIR.
                     var decl_arena = decl.typed_value.most_recent.arena.?.promote(module.gpa);
                     defer decl.typed_value.most_recent.arena.?.* = decl_arena.state;
                     log.debug("analyze liveness of {s}\n", .{decl.name});
-                    try liveness.analyze(module.gpa, &decl_arena.allocator, func.analysis.success);
+                    try liveness.analyze(module.gpa, &decl_arena.allocator, func.data.body);
+
+                    if (self.verbose_ir) {
+                        func.dump(module.*);
+                    }
                 }
 
                 assert(decl.typed_value.most_recent.typed_value.ty.hasCodeGenBits());
src/config.zig.in
@@ -2,7 +2,6 @@ pub const have_llvm = true;
 pub const version: [:0]const u8 = "@ZIG_VERSION@";
 pub const semver = try @import("std").SemanticVersion.parse(version);
 pub const log_scopes: []const []const u8 = &[_][]const u8{};
-pub const zir_dumps: []const []const u8 = &[_][]const u8{};
 pub const enable_tracy = false;
 pub const is_stage1 = true;
 pub const skip_non_native = false;
src/llvm_backend.zig
@@ -294,7 +294,7 @@ pub const LLVMIRModule = struct {
                 const entry_block = llvm_func.appendBasicBlock("Entry");
                 self.builder.positionBuilderAtEnd(entry_block);
 
-                const instructions = func.analysis.success.instructions;
+                const instructions = func.data.body.instructions;
                 for (instructions) |inst| {
                     switch (inst.tag) {
                         .breakpoint => try self.genBreakpoint(inst.castTag(.breakpoint).?),
src/Module.zig
@@ -286,23 +286,40 @@ pub const Decl = struct {
 /// Extern functions do not have this data structure; they are represented by
 /// the `Decl` only, with a `Value` tag of `extern_fn`.
 pub const Fn = struct {
-    /// This memory owned by the Decl's TypedValue.Managed arena allocator.
-    analysis: union(enum) {
+    bits: packed struct {
+        /// Get and set this field via `analysis` and `setAnalysis`.
+        state: Analysis.Tag,
+        /// We carry this state into `Fn` instead of leaving it in the AST so that
+        /// analysis of function calls can happen even on functions whose AST has
+        /// been unloaded from memory.
+        is_inline: bool,
+        unused_bits: u4 = 0,
+    },
+    /// Get and set this data via `analysis` and `setAnalysis`.
+    data: union {
+        none: void,
+        zir: *ZIR,
+        body: Body,
+    },
+    owner_decl: *Decl,
+
+    pub const Analysis = union(Tag) {
         queued: *ZIR,
         in_progress,
-        /// There will be a corresponding ErrorMsg in Module.failed_decls
         sema_failure,
-        /// This Fn might be OK but it depends on another Decl which did not successfully complete
-        /// semantic analysis.
         dependency_failure,
         success: Body,
-    },
-    owner_decl: *Decl,
 
-    /// This memory is temporary and points to stack memory for the duration
-    /// of Fn analysis.
-    pub const Analysis = struct {
-        inner_block: Scope.Block,
+        pub const Tag = enum(u3) {
+            queued,
+            in_progress,
+            /// There will be a corresponding ErrorMsg in Module.failed_decls
+            sema_failure,
+            /// This Fn might be OK but it depends on another Decl which did not
+            /// successfully complete semantic analysis.
+            dependency_failure,
+            success,
+        };
     };
 
     /// Contains un-analyzed ZIR instructions generated from Zig source AST.
@@ -311,22 +328,37 @@ pub const Fn = struct {
         arena: std.heap.ArenaAllocator.State,
     };
 
-    /// For debugging purposes.
-    pub fn dump(self: *Fn, mod: Module) void {
-        std.debug.print("Module.Function(name={s}) ", .{self.owner_decl.name});
-        switch (self.analysis) {
-            .queued => {
-                std.debug.print("queued\n", .{});
+    pub fn analysis(self: Fn) Analysis {
+        return switch (self.bits.state) {
+            .queued => .{ .queued = self.data.zir },
+            .success => .{ .success = self.data.body },
+            .in_progress => .in_progress,
+            .sema_failure => .sema_failure,
+            .dependency_failure => .dependency_failure,
+        };
+    }
+
+    pub fn setAnalysis(self: *Fn, anal: Analysis) void {
+        switch (anal) {
+            .queued => |zir_ptr| {
+                self.bits.state = .queued;
+                self.data = .{ .zir = zir_ptr };
             },
-            .in_progress => {
-                std.debug.print("in_progress\n", .{});
+            .success => |body| {
+                self.bits.state = .success;
+                self.data = .{ .body = body };
             },
-            else => {
-                std.debug.print("\n", .{});
-                zir.dumpFn(mod, self);
+            .in_progress, .sema_failure, .dependency_failure => {
+                self.bits.state = anal;
+                self.data = .{ .none = {} };
             },
         }
     }
+
+    /// For debugging purposes.
+    pub fn dump(self: *Fn, mod: Module) void {
+        zir.dumpFn(mod, self);
+    }
 };
 
 pub const Var = struct {
@@ -773,13 +805,33 @@ pub const Scope = struct {
         instructions: ArrayListUnmanaged(*Inst),
         /// Points to the arena allocator of DeclAnalysis
         arena: *Allocator,
-        label: ?Label = null,
+        label: Label = Label.none,
         is_comptime: bool,
 
-        pub const Label = struct {
-            zir_block: *zir.Inst.Block,
-            results: ArrayListUnmanaged(*Inst),
-            block_inst: *Inst.Block,
+        pub const Label = union(enum) {
+            none,
+            /// This `Block` maps a block ZIR instruction to the corresponding
+            /// TZIR instruction for break instruction analysis.
+            breaking: struct {
+                zir_block: *zir.Inst.Block,
+                merges: Merges,
+            },
+            /// This `Block` indicates that an inline function call is happening
+            /// and return instructions should be analyzed as a break instruction
+            /// to this TZIR block instruction.
+            inlining: struct {
+                /// We use this to count from 0 so that arg instructions know
+                /// which parameter index they are, without having to store
+                /// a parameter index with each arg instruction.
+                param_index: usize,
+                casted_args: []*Inst,
+                merges: Merges,
+            },
+
+            pub const Merges = struct {
+                results: ArrayListUnmanaged(*Inst),
+                block_inst: *Inst.Block,
+            };
         };
 
         /// For debugging purposes.
@@ -1189,8 +1241,21 @@ fn astGenAndAnalyzeDecl(self: *Module, decl: *Decl) !bool {
                 break :blk fn_zir;
             };
 
+            const is_inline = blk: {
+                if (fn_proto.getExternExportInlineToken()) |maybe_inline_token| {
+                    if (tree.token_ids[maybe_inline_token] == .Keyword_inline) {
+                        break :blk true;
+                    }
+                }
+                break :blk false;
+            };
+
             new_func.* = .{
-                .analysis = .{ .queued = fn_zir },
+                .bits = .{
+                    .state = .queued,
+                    .is_inline = is_inline,
+                },
+                .data = .{ .zir = fn_zir },
                 .owner_decl = decl,
             };
             fn_payload.* = .{
@@ -1199,11 +1264,16 @@ fn astGenAndAnalyzeDecl(self: *Module, decl: *Decl) !bool {
             };
 
             var prev_type_has_bits = false;
+            var prev_is_inline = false;
             var type_changed = true;
 
             if (decl.typedValueManaged()) |tvm| {
                 prev_type_has_bits = tvm.typed_value.ty.hasCodeGenBits();
                 type_changed = !tvm.typed_value.ty.eql(fn_type);
+                if (tvm.typed_value.val.castTag(.function)) |payload| {
+                    const prev_func = payload.data;
+                    prev_is_inline = prev_func.bits.is_inline;
+                }
 
                 tvm.deinit(self.gpa);
             }
@@ -1221,18 +1291,26 @@ fn astGenAndAnalyzeDecl(self: *Module, decl: *Decl) !bool {
             decl.analysis = .complete;
             decl.generation = self.generation;
 
-            if (fn_type.hasCodeGenBits()) {
+            if (!is_inline and fn_type.hasCodeGenBits()) {
                 // We don't fully codegen the decl until later, but we do need to reserve a global
                 // offset table index for it. This allows us to codegen decls out of dependency order,
                 // increasing how many computations can be done in parallel.
                 try self.comp.bin_file.allocateDeclIndexes(decl);
                 try self.comp.work_queue.writeItem(.{ .codegen_decl = decl });
-            } else if (prev_type_has_bits) {
+            } else if (!prev_is_inline and prev_type_has_bits) {
                 self.comp.bin_file.freeDecl(decl);
             }
 
             if (fn_proto.getExternExportInlineToken()) |maybe_export_token| {
                 if (tree.token_ids[maybe_export_token] == .Keyword_export) {
+                    if (is_inline) {
+                        return self.failTok(
+                            &block_scope.base,
+                            maybe_export_token,
+                            "export of inline function",
+                            .{},
+                        );
+                    }
                     const export_src = tree.token_locs[maybe_export_token].start;
                     const name_loc = tree.token_locs[fn_proto.getNameToken().?];
                     const name = tree.tokenSliceLoc(name_loc);
@@ -1240,7 +1318,7 @@ fn astGenAndAnalyzeDecl(self: *Module, decl: *Decl) !bool {
                     try self.analyzeExport(&block_scope.base, export_src, name, decl);
                 }
             }
-            return type_changed;
+            return type_changed or is_inline != prev_is_inline;
         },
         .VarDecl => {
             const var_decl = @fieldParentPtr(ast.Node.VarDecl, "base", ast_node);
@@ -1824,15 +1902,15 @@ pub fn analyzeFnBody(self: *Module, decl: *Decl, func: *Fn) !void {
     };
     defer inner_block.instructions.deinit(self.gpa);
 
-    const fn_zir = func.analysis.queued;
+    const fn_zir = func.data.zir;
     defer fn_zir.arena.promote(self.gpa).deinit();
-    func.analysis = .{ .in_progress = {} };
+    func.setAnalysis(.in_progress);
     log.debug("set {s} to in_progress\n", .{decl.name});
 
     try zir_sema.analyzeBody(self, &inner_block.base, fn_zir.body);
 
     const instructions = try arena.allocator.dupe(*Inst, inner_block.instructions.items);
-    func.analysis = .{ .success = .{ .instructions = instructions } };
+    func.setAnalysis(.{ .success = .{ .instructions = instructions } });
     log.debug("set {s} to success\n", .{decl.name});
 }
 
@@ -2329,7 +2407,7 @@ pub fn analyzeDeclRef(self: *Module, scope: *Scope, src: usize, decl: *Decl) Inn
     self.ensureDeclAnalyzed(decl) catch |err| {
         if (scope.cast(Scope.Block)) |block| {
             if (block.func) |func| {
-                func.analysis = .dependency_failure;
+                func.setAnalysis(.dependency_failure);
             } else {
                 block.decl.analysis = .dependency_failure;
             }
@@ -3029,7 +3107,7 @@ fn failWithOwnedErrorMsg(self: *Module, scope: *Scope, src: usize, err_msg: *Com
         .block => {
             const block = scope.cast(Scope.Block).?;
             if (block.func) |func| {
-                func.analysis = .sema_failure;
+                func.setAnalysis(.sema_failure);
             } else {
                 block.decl.analysis = .sema_failure;
                 block.decl.generation = self.generation;
src/zir.zig
@@ -793,7 +793,9 @@ pub const Inst = struct {
             fn_type: *Inst,
             body: Module.Body,
         },
-        kw_args: struct {},
+        kw_args: struct {
+            is_inline: bool = false,
+        },
     };
 
     pub const FnType = struct {
@@ -1847,83 +1849,258 @@ pub fn emit(allocator: *Allocator, old_module: *IrModule) !Module {
 /// For debugging purposes, prints a function representation to stderr.
 pub fn dumpFn(old_module: IrModule, module_fn: *IrModule.Fn) void {
     const allocator = old_module.gpa;
-    var ctx: EmitZIR = .{
+    var ctx: DumpTzir = .{
         .allocator = allocator,
-        .decls = .{},
         .arena = std.heap.ArenaAllocator.init(allocator),
         .old_module = &old_module,
-        .next_auto_name = 0,
-        .names = std.StringArrayHashMap(void).init(allocator),
-        .primitive_table = std.AutoHashMap(Inst.Primitive.Builtin, *Decl).init(allocator),
-        .indent = 0,
-        .block_table = std.AutoHashMap(*ir.Inst.Block, *Inst.Block).init(allocator),
-        .loop_table = std.AutoHashMap(*ir.Inst.Loop, *Inst.Loop).init(allocator),
-        .metadata = std.AutoHashMap(*Inst, Module.MetaData).init(allocator),
-        .body_metadata = std.AutoHashMap(*Module.Body, Module.BodyMetaData).init(allocator),
+        .module_fn = module_fn,
+        .indent = 2,
+        .inst_table = DumpTzir.InstTable.init(allocator),
+        .partial_inst_table = DumpTzir.InstTable.init(allocator),
+        .const_table = DumpTzir.InstTable.init(allocator),
     };
-    defer ctx.metadata.deinit();
-    defer ctx.body_metadata.deinit();
-    defer ctx.block_table.deinit();
-    defer ctx.loop_table.deinit();
-    defer ctx.decls.deinit(allocator);
-    defer ctx.names.deinit();
-    defer ctx.primitive_table.deinit();
+    defer ctx.inst_table.deinit();
+    defer ctx.partial_inst_table.deinit();
+    defer ctx.const_table.deinit();
     defer ctx.arena.deinit();
 
-    const fn_ty = module_fn.owner_decl.typed_value.most_recent.typed_value.ty;
-    _ = ctx.emitFn(module_fn, 0, fn_ty) catch |err| {
-        std.debug.print("unable to dump function: {s}\n", .{@errorName(err)});
-        return;
-    };
-    var module = Module{
-        .decls = ctx.decls.items,
-        .arena = ctx.arena,
-        .metadata = ctx.metadata,
-        .body_metadata = ctx.body_metadata,
-    };
-
-    module.dump();
+    switch (module_fn.analysis()) {
+        .queued => std.debug.print("(queued)", .{}),
+        .in_progress => std.debug.print("(in_progress)", .{}),
+        .sema_failure => std.debug.print("(sema_failure)", .{}),
+        .dependency_failure => std.debug.print("(dependency_failure)", .{}),
+        .success => |body| {
+            ctx.dump(body, std.io.getStdErr().writer()) catch @panic("failed to dump TZIR");
+        },
+    }
 }
 
-/// For debugging purposes, prints a function representation to stderr.
-pub fn dumpBlock(old_module: IrModule, module_block: *IrModule.Scope.Block) void {
-    const allocator = old_module.gpa;
-    var ctx: EmitZIR = .{
-        .allocator = allocator,
-        .decls = .{},
-        .arena = std.heap.ArenaAllocator.init(allocator),
-        .old_module = &old_module,
-        .next_auto_name = 0,
-        .names = std.StringArrayHashMap(void).init(allocator),
-        .primitive_table = std.AutoHashMap(Inst.Primitive.Builtin, *Decl).init(allocator),
-        .indent = 0,
-        .block_table = std.AutoHashMap(*ir.Inst.Block, *Inst.Block).init(allocator),
-        .loop_table = std.AutoHashMap(*ir.Inst.Loop, *Inst.Loop).init(allocator),
-        .metadata = std.AutoHashMap(*Inst, Module.MetaData).init(allocator),
-        .body_metadata = std.AutoHashMap(*Module.Body, Module.BodyMetaData).init(allocator),
-    };
-    defer ctx.metadata.deinit();
-    defer ctx.body_metadata.deinit();
-    defer ctx.block_table.deinit();
-    defer ctx.loop_table.deinit();
-    defer ctx.decls.deinit(allocator);
-    defer ctx.names.deinit();
-    defer ctx.primitive_table.deinit();
-    defer ctx.arena.deinit();
+const DumpTzir = struct {
+    allocator: *Allocator,
+    arena: std.heap.ArenaAllocator,
+    old_module: *const IrModule,
+    module_fn: *IrModule.Fn,
+    indent: usize,
+    inst_table: InstTable,
+    partial_inst_table: InstTable,
+    const_table: InstTable,
+    next_index: usize = 0,
+    next_partial_index: usize = 0,
+    next_const_index: usize = 0,
+
+    const InstTable = std.AutoArrayHashMap(*ir.Inst, usize);
+
+    fn dump(dtz: *DumpTzir, body: ir.Body, writer: std.fs.File.Writer) !void {
+        // First pass to pre-populate the table so that we can show even invalid references.
+        // Must iterate the same order we iterate the second time.
+        // We also look for constants and put them in the const_table.
+        for (body.instructions) |inst| {
+            try dtz.inst_table.put(inst, dtz.next_index);
+            dtz.next_index += 1;
+            switch (inst.tag) {
+                .alloc,
+                .retvoid,
+                .unreach,
+                .breakpoint,
+                .dbg_stmt,
+                => {},
 
-    _ = ctx.emitBlock(module_block, 0) catch |err| {
-        std.debug.print("unable to dump function: {}\n", .{err});
-        return;
-    };
-    var module = Module{
-        .decls = ctx.decls.items,
-        .arena = ctx.arena,
-        .metadata = ctx.metadata,
-        .body_metadata = ctx.body_metadata,
-    };
+                .ref,
+                .ret,
+                .bitcast,
+                .not,
+                .isnonnull,
+                .isnull,
+                .iserr,
+                .ptrtoint,
+                .floatcast,
+                .intcast,
+                .load,
+                .unwrap_optional,
+                .wrap_optional,
+                => {
+                    const un_op = inst.cast(ir.Inst.UnOp).?;
+                    try dtz.findConst(un_op.operand);
+                },
 
-    module.dump();
-}
+                .add,
+                .sub,
+                .cmp_lt,
+                .cmp_lte,
+                .cmp_eq,
+                .cmp_gte,
+                .cmp_gt,
+                .cmp_neq,
+                .store,
+                .booland,
+                .boolor,
+                .bitand,
+                .bitor,
+                .xor,
+                => {
+                    const bin_op = inst.cast(ir.Inst.BinOp).?;
+                    try dtz.findConst(bin_op.lhs);
+                    try dtz.findConst(bin_op.rhs);
+                },
+
+                .arg => {},
+
+                // TODO fill out this debug printing
+                .assembly,
+                .block,
+                .br,
+                .brvoid,
+                .call,
+                .condbr,
+                .constant,
+                .loop,
+                .varptr,
+                .switchbr,
+                => {},
+            }
+        }
+
+        std.debug.print("Module.Function(name={s}):\n", .{dtz.module_fn.owner_decl.name});
+
+        for (dtz.const_table.items()) |entry| {
+            const constant = entry.key.castTag(.constant).?;
+            try writer.print("  @{d}: {} = {};\n", .{
+                entry.value, constant.base.ty, constant.val,
+            });
+        }
+
+        return dtz.dumpBody(body, writer);
+    }
+
+    fn dumpBody(dtz: *DumpTzir, body: ir.Body, writer: std.fs.File.Writer) !void {
+        for (body.instructions) |inst| {
+            const my_index = dtz.next_partial_index;
+            try dtz.partial_inst_table.put(inst, my_index);
+            dtz.next_partial_index += 1;
+
+            try writer.writeByteNTimes(' ', dtz.indent);
+            try writer.print("%{d}: {} = {s}(", .{
+                my_index, inst.ty, @tagName(inst.tag),
+            });
+            switch (inst.tag) {
+                .alloc,
+                .retvoid,
+                .unreach,
+                .breakpoint,
+                .dbg_stmt,
+                => try writer.writeAll(")\n"),
+
+                .ref,
+                .ret,
+                .bitcast,
+                .not,
+                .isnonnull,
+                .isnull,
+                .iserr,
+                .ptrtoint,
+                .floatcast,
+                .intcast,
+                .load,
+                .unwrap_optional,
+                .wrap_optional,
+                => {
+                    const un_op = inst.cast(ir.Inst.UnOp).?;
+                    if (dtz.partial_inst_table.get(un_op.operand)) |operand_index| {
+                        try writer.print("%{d})\n", .{operand_index});
+                    } else if (dtz.const_table.get(un_op.operand)) |operand_index| {
+                        try writer.print("@{d})\n", .{operand_index});
+                    } else if (dtz.inst_table.get(un_op.operand)) |operand_index| {
+                        try writer.print("%{d}) // Instruction does not dominate all uses!\n", .{
+                            operand_index,
+                        });
+                    } else {
+                        try writer.writeAll("!BADREF!)\n");
+                    }
+                },
+
+                .add,
+                .sub,
+                .cmp_lt,
+                .cmp_lte,
+                .cmp_eq,
+                .cmp_gte,
+                .cmp_gt,
+                .cmp_neq,
+                .store,
+                .booland,
+                .boolor,
+                .bitand,
+                .bitor,
+                .xor,
+                => {
+                    var lhs_kinky: ?usize = null;
+                    var rhs_kinky: ?usize = null;
+
+                    const bin_op = inst.cast(ir.Inst.BinOp).?;
+                    if (dtz.partial_inst_table.get(bin_op.lhs)) |operand_index| {
+                        try writer.print("%{d}, ", .{operand_index});
+                    } else if (dtz.const_table.get(bin_op.lhs)) |operand_index| {
+                        try writer.print("@{d}, ", .{operand_index});
+                    } else if (dtz.inst_table.get(bin_op.lhs)) |operand_index| {
+                        lhs_kinky = operand_index;
+                        try writer.print("%{d}, ", .{operand_index});
+                    } else {
+                        try writer.writeAll("!BADREF!, ");
+                    }
+                    if (dtz.partial_inst_table.get(bin_op.rhs)) |operand_index| {
+                        try writer.print("%{d}", .{operand_index});
+                    } else if (dtz.const_table.get(bin_op.rhs)) |operand_index| {
+                        try writer.print("@{d}", .{operand_index});
+                    } else if (dtz.inst_table.get(bin_op.rhs)) |operand_index| {
+                        rhs_kinky = operand_index;
+                        try writer.print("%{d}", .{operand_index});
+                    } else {
+                        try writer.writeAll("!BADREF!");
+                    }
+                    if (lhs_kinky != null or rhs_kinky != null) {
+                        try writer.writeAll(") // Instruction does not dominate all uses!");
+                        if (lhs_kinky) |lhs| {
+                            try writer.print(" %{d}", .{lhs});
+                        }
+                        if (rhs_kinky) |rhs| {
+                            try writer.print(" %{d}", .{rhs});
+                        }
+                        try writer.writeAll("\n");
+                    } else {
+                        try writer.writeAll(")\n");
+                    }
+                },
+
+                .arg => {
+                    const arg = inst.castTag(.arg).?;
+                    try writer.print("{s})\n", .{arg.name});
+                },
+
+                // TODO fill out this debug printing
+                .assembly,
+                .block,
+                .br,
+                .brvoid,
+                .call,
+                .condbr,
+                .constant,
+                .loop,
+                .varptr,
+                .switchbr,
+                => {
+                    try writer.writeAll("!TODO!)\n");
+                },
+            }
+        }
+    }
+
+    fn findConst(dtz: *DumpTzir, operand: *ir.Inst) !void {
+        if (operand.tag == .constant) {
+            try dtz.const_table.put(operand, dtz.next_const_index);
+            dtz.next_const_index += 1;
+        }
+    }
+};
 
 const EmitZIR = struct {
     allocator: *Allocator,
@@ -2105,36 +2282,6 @@ const EmitZIR = struct {
         return &declref_inst.base;
     }
 
-    fn emitBlock(self: *EmitZIR, module_block: *IrModule.Scope.Block, src: usize) Allocator.Error!*Decl {
-        var inst_table = std.AutoHashMap(*ir.Inst, *Inst).init(self.allocator);
-        defer inst_table.deinit();
-
-        var instructions = std.ArrayList(*Inst).init(self.allocator);
-        defer instructions.deinit();
-
-        const body: ir.Body = .{ .instructions = module_block.instructions.items };
-        try self.emitBody(body, &inst_table, &instructions);
-
-        const fn_type = try self.emitType(src, Type.initTag(.void));
-
-        const arena_instrs = try self.arena.allocator.alloc(*Inst, instructions.items.len);
-        mem.copy(*Inst, arena_instrs, instructions.items);
-
-        const fn_inst = try self.arena.allocator.create(Inst.Fn);
-        fn_inst.* = .{
-            .base = .{
-                .src = src,
-                .tag = Inst.Fn.base_tag,
-            },
-            .positionals = .{
-                .fn_type = fn_type.inst,
-                .body = .{ .instructions = arena_instrs },
-            },
-            .kw_args = .{},
-        };
-        return self.emitUnnamedDecl(&fn_inst.base);
-    }
-
     fn emitFn(self: *EmitZIR, module_fn: *IrModule.Fn, src: usize, ty: Type) Allocator.Error!*Decl {
         var inst_table = std.AutoHashMap(*ir.Inst, *Inst).init(self.allocator);
         defer inst_table.deinit();
@@ -2142,7 +2289,7 @@ const EmitZIR = struct {
         var instructions = std.ArrayList(*Inst).init(self.allocator);
         defer instructions.deinit();
 
-        switch (module_fn.analysis) {
+        switch (module_fn.analysis()) {
             .queued => unreachable,
             .in_progress => unreachable,
             .success => |body| {
@@ -2224,7 +2371,9 @@ const EmitZIR = struct {
                 .fn_type = fn_type.inst,
                 .body = .{ .instructions = arena_instrs },
             },
-            .kw_args = .{},
+            .kw_args = .{
+                .is_inline = module_fn.bits.is_inline,
+            },
         };
         return self.emitUnnamedDecl(&fn_inst.base);
     }
src/zir_sema.zig
@@ -577,7 +577,15 @@ fn analyzeInstCompileError(mod: *Module, scope: *Scope, inst: *zir.Inst.UnOp) In
 }
 
 fn analyzeInstArg(mod: *Module, scope: *Scope, inst: *zir.Inst.Arg) InnerError!*Inst {
-    const b = try mod.requireRuntimeBlock(scope, inst.base.src);
+    const b = try mod.requireFunctionBlock(scope, inst.base.src);
+    switch (b.label) {
+        .none, .breaking => {},
+        .inlining => |*inlining| {
+            const param_index = inlining.param_index;
+            inlining.param_index += 1;
+            return inlining.casted_args[param_index];
+        },
+    }
     const fn_ty = b.func.?.owner_decl.typed_value.most_recent.typed_value.ty;
     const param_index = b.instructions.items.len;
     const param_count = fn_ty.fnParamLen();
@@ -636,7 +644,7 @@ fn analyzeInstBlockFlat(mod: *Module, scope: *Scope, inst: *zir.Inst.Block, is_c
         .decl = parent_block.decl,
         .instructions = .{},
         .arena = parent_block.arena,
-        .label = null,
+        .label = .none,
         .is_comptime = parent_block.is_comptime or is_comptime,
     };
     defer child_block.instructions.deinit(mod.gpa);
@@ -674,41 +682,56 @@ fn analyzeInstBlock(mod: *Module, scope: *Scope, inst: *zir.Inst.Block, is_compt
         .decl = parent_block.decl,
         .instructions = .{},
         .arena = parent_block.arena,
-        // TODO @as here is working around a stage1 miscompilation bug :(
-        .label = @as(?Scope.Block.Label, Scope.Block.Label{
-            .zir_block = inst,
-            .results = .{},
-            .block_inst = block_inst,
-        }),
+        .label = Scope.Block.Label{
+            .breaking = .{
+                .zir_block = inst,
+                .merges = .{
+                    .results = .{},
+                    .block_inst = block_inst,
+                },
+            },
+        },
         .is_comptime = is_comptime or parent_block.is_comptime,
     };
-    const label = &child_block.label.?;
+    const merges = &child_block.label.breaking.merges;
 
     defer child_block.instructions.deinit(mod.gpa);
-    defer label.results.deinit(mod.gpa);
+    defer merges.results.deinit(mod.gpa);
 
     try analyzeBody(mod, &child_block.base, inst.positionals.body);
 
+    return analyzeBlockBody(mod, scope, &child_block, merges);
+}
+
+fn analyzeBlockBody(
+    mod: *Module,
+    scope: *Scope,
+    child_block: *Scope.Block,
+    merges: *Scope.Block.Label.Merges,
+) InnerError!*Inst {
+    const parent_block = scope.cast(Scope.Block).?;
+
     // Blocks must terminate with noreturn instruction.
     assert(child_block.instructions.items.len != 0);
     assert(child_block.instructions.items[child_block.instructions.items.len - 1].ty.isNoReturn());
 
-    if (label.results.items.len == 0) {
-        // No need for a block instruction. We can put the new instructions directly into the parent block.
+    if (merges.results.items.len == 0) {
+        // No need for a block instruction. We can put the new instructions
+        // directly into the parent block.
         const copied_instructions = try parent_block.arena.dupe(*Inst, child_block.instructions.items);
         try parent_block.instructions.appendSlice(mod.gpa, copied_instructions);
         return copied_instructions[copied_instructions.len - 1];
     }
-    if (label.results.items.len == 1) {
+    if (merges.results.items.len == 1) {
         const last_inst_index = child_block.instructions.items.len - 1;
         const last_inst = child_block.instructions.items[last_inst_index];
         if (last_inst.breakBlock()) |br_block| {
-            if (br_block == block_inst) {
+            if (br_block == merges.block_inst) {
                 // No need for a block instruction. We can put the new instructions directly into the parent block.
                 // Here we omit the break instruction.
                 const copied_instructions = try parent_block.arena.dupe(*Inst, child_block.instructions.items[0..last_inst_index]);
                 try parent_block.instructions.appendSlice(mod.gpa, copied_instructions);
-                return label.results.items[0];
+                return merges.results.items[0];
             }
         }
     }
@@ -717,10 +740,10 @@ fn analyzeInstBlock(mod: *Module, scope: *Scope, inst: *zir.Inst.Block, is_compt
 
     // Need to set the type and emit the Block instruction. This allows machine code generation
     // to emit a jump instruction to after the block when it encounters the break.
-    try parent_block.instructions.append(mod.gpa, &block_inst.base);
-    block_inst.base.ty = try mod.resolvePeerTypes(scope, label.results.items);
-    block_inst.body = .{ .instructions = try parent_block.arena.dupe(*Inst, child_block.instructions.items) };
-    return &block_inst.base;
+    try parent_block.instructions.append(mod.gpa, &merges.block_inst.base);
+    merges.block_inst.base.ty = try mod.resolvePeerTypes(scope, merges.results.items);
+    merges.block_inst.body = .{ .instructions = try parent_block.arena.dupe(*Inst, child_block.instructions.items) };
+    return &merges.block_inst.base;
 }
 
 fn analyzeInstBreakpoint(mod: *Module, scope: *Scope, inst: *zir.Inst.NoOp) InnerError!*Inst {
@@ -829,14 +852,32 @@ fn analyzeInstCall(mod: *Module, scope: *Scope, inst: *zir.Inst.Call) InnerError
     const ret_type = func.ty.fnReturnType();
 
     const b = try mod.requireFunctionBlock(scope, inst.base.src);
-    if (b.is_comptime) {
-        const fn_val = try mod.resolveConstValue(scope, func);
-        const module_fn = switch (fn_val.tag()) {
-            .function => fn_val.castTag(.function).?.data,
-            .extern_fn => return mod.fail(scope, inst.base.src, "comptime call of extern function", .{}),
+    const is_comptime_call = b.is_comptime or inst.kw_args.modifier == .compile_time;
+    const is_inline_call = is_comptime_call or inst.kw_args.modifier == .always_inline or blk: {
+        // This logic will get simplified by
+        // https://github.com/ziglang/zig/issues/6429
+        if (try mod.resolveDefinedValue(scope, func)) |func_val| {
+            const module_fn = switch (func_val.tag()) {
+                .function => func_val.castTag(.function).?.data,
+                else => break :blk false,
+            };
+            break :blk module_fn.bits.is_inline;
+        }
+        break :blk false;
+    };
+    if (is_inline_call) {
+        const func_val = try mod.resolveConstValue(scope, func);
+        const module_fn = switch (func_val.tag()) {
+            .function => func_val.castTag(.function).?.data,
+            .extern_fn => return mod.fail(scope, inst.base.src, "{s} call of extern function", .{
+                @as([]const u8, if (is_comptime_call) "comptime" else "inline"),
+            }),
             else => unreachable,
         };
         const callee_decl = module_fn.owner_decl;
+        // TODO: De-duplicate this with the code in Module.zig that generates
+        // ZIR for the same function and re-use the same ZIR for runtime function
+        // generation and for inline/comptime calls.
         const callee_file_scope = callee_decl.getFileScope();
         const tree = mod.getAstTree(callee_file_scope) catch |err| switch (err) {
             error.OutOfMemory => return error.OutOfMemory,
@@ -859,23 +900,31 @@ fn analyzeInstCall(mod: *Module, scope: *Scope, inst: *zir.Inst.Call) InnerError
         };
         defer gen_scope.instructions.deinit(mod.gpa);
 
-        // Add a const instruction for each parameter.
+        // We need an instruction for each parameter, and they must be first in the body.
+        try gen_scope.instructions.resize(mod.gpa, fn_proto.params_len);
         var params_scope = &gen_scope.base;
         for (fn_proto.params()) |param, i| {
             const name_token = param.name_token.?;
             const src = tree.token_locs[name_token].start;
             const param_name = try mod.identifierTokenString(scope, name_token);
-            const arg_val = try mod.resolveConstValue(scope, casted_args[i]);
-            const arg = try astgen.addZIRInstConst(mod, params_scope, src, .{
-                .ty = casted_args[i].ty,
-                .val = arg_val,
-            });
+            const arg = try call_arena.allocator.create(zir.Inst.Arg);
+            arg.* = .{
+                .base = .{
+                    .tag = .arg,
+                    .src = src,
+                },
+                .positionals = .{
+                    .name = param_name,
+                },
+                .kw_args = .{},
+            };
+            gen_scope.instructions.items[i] = &arg.base;
             const sub_scope = try call_arena.allocator.create(Scope.LocalVal);
             sub_scope.* = .{
                 .parent = params_scope,
                 .gen_zir = &gen_scope,
                 .name = param_name,
-                .inst = arg,
+                .inst = &arg.base,
             };
             params_scope = &sub_scope.base;
         }
@@ -896,42 +945,52 @@ fn analyzeInstCall(mod: *Module, scope: *Scope, inst: *zir.Inst.Call) InnerError
             zir.dumpZir(mod.gpa, "fn_body_callee", callee_decl.name, gen_scope.instructions.items) catch {};
         }
 
-        // Analyze the ZIR.
-        var inner_block: Scope.Block = .{
+        // Analyze the ZIR. The same ZIR gets analyzed into a runtime function
+        // or an inlined call depending on what union tag the `label` field is
+        // set to in the `Scope.Block`.
+        // This block instruction will be used to capture the return value from the
+        // inlined function.
+        const block_inst = try scope.arena().create(Inst.Block);
+        block_inst.* = .{
+            .base = .{
+                .tag = Inst.Block.base_tag,
+                .ty = ret_type,
+                .src = inst.base.src,
+            },
+            .body = undefined,
+        };
+        var child_block: Scope.Block = .{
             .parent = null,
             .func = module_fn,
-            .decl = callee_decl,
+            // Note that we pass the caller's Decl, not the callee. This causes
+            // compile errors to be attached (correctly) to the caller's Decl.
+            .decl = scope.decl().?,
             .instructions = .{},
-            .arena = &call_arena.allocator,
-            .is_comptime = true,
+            .arena = scope.arena(),
+            .label = Scope.Block.Label{
+                .inlining = .{
+                    .param_index = 0,
+                    .casted_args = casted_args,
+                    .merges = .{
+                        .results = .{},
+                        .block_inst = block_inst,
+                    },
+                },
+            },
+            .is_comptime = is_comptime_call,
         };
-        defer inner_block.instructions.deinit(mod.gpa);
+        const merges = &child_block.label.inlining.merges;
+
+        defer child_block.instructions.deinit(mod.gpa);
+        defer merges.results.deinit(mod.gpa);
 
-        // TODO make sure compile errors that happen from this analyzeBody are reported correctly
-        // and attach to the caller Decl not the callee.
-        try analyzeBody(mod, &inner_block.base, .{
+        // This will have return instructions analyzed as break instructions to
+        // the block_inst above.
+        try analyzeBody(mod, &child_block.base, .{
             .instructions = gen_scope.instructions.items,
         });
 
-        if (mod.comp.verbose_ir) {
-            inner_block.dump(mod.*);
-        }
-
-        assert(inner_block.instructions.items.len == 1);
-        const only_inst = inner_block.instructions.items[0];
-        switch (only_inst.tag) {
-            .ret => {
-                const ret_inst = only_inst.castTag(.ret).?;
-                const operand = ret_inst.operand;
-                const callee_arena = scope.arena();
-                return mod.constInst(scope, inst.base.src, .{
-                    .ty = try operand.ty.copy(callee_arena),
-                    .val = try operand.value().?.copy(callee_arena),
-                });
-            },
-            .retvoid => return mod.constVoid(scope, inst.base.src),
-            else => unreachable,
-        }
+        return analyzeBlockBody(mod, scope, &child_block, merges);
     }
 
     return mod.addCall(b, inst.base.src, ret_type, func, casted_args);
@@ -954,7 +1013,11 @@ fn analyzeInstFn(mod: *Module, scope: *Scope, fn_inst: *zir.Inst.Fn) InnerError!
     };
     const new_func = try scope.arena().create(Module.Fn);
     new_func.* = .{
-        .analysis = .{ .queued = fn_zir },
+        .bits = .{
+            .state = .queued,
+            .is_inline = fn_inst.kw_args.is_inline,
+        },
+        .data = .{ .zir = fn_zir },
         .owner_decl = scope.decl().?,
     };
     return mod.constInst(scope, fn_inst.base.src, .{
@@ -2020,21 +2083,41 @@ fn analyzeInstUnreachable(
 fn analyzeInstRet(mod: *Module, scope: *Scope, inst: *zir.Inst.UnOp) InnerError!*Inst {
     const operand = try resolveInst(mod, scope, inst.positionals.operand);
     const b = try mod.requireFunctionBlock(scope, inst.base.src);
-    return mod.addUnOp(b, inst.base.src, Type.initTag(.noreturn), .ret, operand);
+
+    switch (b.label) {
+        .inlining => |*inlining| {
+            // We are inlining a function call; rewrite the `ret` as a `break`.
+            try inlining.merges.results.append(mod.gpa, operand);
+            return mod.addBr(b, inst.base.src, inlining.merges.block_inst, operand);
+        },
+        .none, .breaking => {
+            return mod.addUnOp(b, inst.base.src, Type.initTag(.noreturn), .ret, operand);
+        },
+    }
 }
 
 fn analyzeInstRetVoid(mod: *Module, scope: *Scope, inst: *zir.Inst.NoOp) InnerError!*Inst {
     const b = try mod.requireFunctionBlock(scope, inst.base.src);
-    if (b.func) |func| {
-        // Need to emit a compile error if returning void is not allowed.
-        const void_inst = try mod.constVoid(scope, inst.base.src);
-        const fn_ty = func.owner_decl.typed_value.most_recent.typed_value.ty;
-        const casted_void = try mod.coerce(scope, fn_ty.fnReturnType(), void_inst);
-        if (casted_void.ty.zigTypeTag() != .Void) {
-            return mod.addUnOp(b, inst.base.src, Type.initTag(.noreturn), .ret, casted_void);
-        }
+    switch (b.label) {
+        .inlining => |*inlining| {
+            // We are inlining a function call; rewrite the `retvoid` as a `breakvoid`.
+            const void_inst = try mod.constVoid(scope, inst.base.src);
+            try inlining.merges.results.append(mod.gpa, void_inst);
+            return mod.addBr(b, inst.base.src, inlining.merges.block_inst, void_inst);
+        },
+        .none, .breaking => {
+            if (b.func) |func| {
+                // Need to emit a compile error if returning void is not allowed.
+                const void_inst = try mod.constVoid(scope, inst.base.src);
+                const fn_ty = func.owner_decl.typed_value.most_recent.typed_value.ty;
+                const casted_void = try mod.coerce(scope, fn_ty.fnReturnType(), void_inst);
+                if (casted_void.ty.zigTypeTag() != .Void) {
+                    return mod.addUnOp(b, inst.base.src, Type.initTag(.noreturn), .ret, casted_void);
+                }
+            }
+            return mod.addNoOp(b, inst.base.src, Type.initTag(.noreturn), .retvoid);
+        },
     }
-    return mod.addNoOp(b, inst.base.src, Type.initTag(.noreturn), .retvoid);
 }
 
 fn floatOpAllowed(tag: zir.Inst.Tag) bool {
@@ -2054,12 +2137,16 @@ fn analyzeBreak(
 ) InnerError!*Inst {
     var opt_block = scope.cast(Scope.Block);
     while (opt_block) |block| {
-        if (block.label) |*label| {
-            if (label.zir_block == zir_block) {
-                try label.results.append(mod.gpa, operand);
-                const b = try mod.requireRuntimeBlock(scope, src);
-                return mod.addBr(b, src, label.block_inst, operand);
-            }
+        switch (block.label) {
+            .none => {},
+            .breaking => |*label| {
+                if (label.zir_block == zir_block) {
+                    try label.merges.results.append(mod.gpa, operand);
+                    const b = try mod.requireFunctionBlock(scope, src);
+                    return mod.addBr(b, src, label.merges.block_inst, operand);
+                }
+            },
+            .inlining => unreachable, // Invalid `break` ZIR inside inline function call.
         }
         opt_block = block.parent;
     } else unreachable;
test/stage2/zir.zig
@@ -30,7 +30,7 @@ pub fn addCases(ctx: *TestContext) !void {
         \\@unnamed$7 = fntype([], @void, cc=C)
         \\@entry = fn(@unnamed$7, {
         \\  %0 = returnvoid() ; deaths=0b1000000000000000
-        \\})
+        \\}, is_inline=0)
         \\
     );
     ctx.transformZIR("elemptr, add, cmp, condbr, return, breakpoint", linux_x64,
@@ -78,7 +78,7 @@ pub fn addCases(ctx: *TestContext) !void {
         \\@unnamed$6 = fntype([], @void, cc=C)
         \\@entry = fn(@unnamed$6, {
         \\  %0 = returnvoid() ; deaths=0b1000000000000000
-        \\})
+        \\}, is_inline=0)
         \\@entry__anon_1 = str("2\x08\x01\n")
         \\@9 = declref("9__anon_0")
         \\@9__anon_0 = str("entry")
@@ -123,17 +123,17 @@ pub fn addCases(ctx: *TestContext) !void {
             \\@entry = fn(@unnamed$7, {
             \\  %0 = call(@a, [], modifier=auto) ; deaths=0b1000000000000001
             \\  %1 = returnvoid() ; deaths=0b1000000000000000
-            \\})
+            \\}, is_inline=0)
             \\@unnamed$9 = fntype([], @void, cc=C)
             \\@a = fn(@unnamed$9, {
             \\  %0 = call(@b, [], modifier=auto) ; deaths=0b1000000000000001
             \\  %1 = returnvoid() ; deaths=0b1000000000000000
-            \\})
+            \\}, is_inline=0)
             \\@unnamed$11 = fntype([], @void, cc=C)
             \\@b = fn(@unnamed$11, {
             \\  %0 = call(@a, [], modifier=auto) ; deaths=0b1000000000000001
             \\  %1 = returnvoid() ; deaths=0b1000000000000000
-            \\})
+            \\}, is_inline=0)
             \\
         );
         // Now we introduce a compile error
@@ -203,7 +203,7 @@ pub fn addCases(ctx: *TestContext) !void {
             \\@unnamed$7 = fntype([], @void, cc=C)
             \\@entry = fn(@unnamed$7, {
             \\  %0 = returnvoid() ; deaths=0b1000000000000000
-            \\})
+            \\}, is_inline=0)
             \\
         );
     }
build.zig
@@ -220,7 +220,6 @@ pub fn build(b: *Builder) !void {
     }
 
     const log_scopes = b.option([]const []const u8, "log", "Which log scopes to enable") orelse &[0][]const u8{};
-    const zir_dumps = b.option([]const []const u8, "dump-zir", "Which functions to dump ZIR for before codegen") orelse &[0][]const u8{};
 
     const opt_version_string = b.option([]const u8, "version-string", "Override Zig version string. Default is to find out with git.");
     const version = if (opt_version_string) |version| version else v: {
@@ -277,7 +276,6 @@ pub fn build(b: *Builder) !void {
     exe.addBuildOption(std.SemanticVersion, "semver", semver);
 
     exe.addBuildOption([]const []const u8, "log_scopes", log_scopes);
-    exe.addBuildOption([]const []const u8, "zir_dumps", zir_dumps);
     exe.addBuildOption(bool, "enable_tracy", tracy != null);
     exe.addBuildOption(bool, "is_stage1", is_stage1);
     if (tracy) |tracy_path| {