Commit 97816e3cb8
Changed files (1)
src
arch
aarch64
src/arch/aarch64/CodeGen.zig
@@ -128,18 +128,11 @@ const MCValue = union(enum) {
register: Register,
/// The value is a tuple { wrapped: u32, overflow: u1 } where
/// wrapped is stored in the register and the overflow bit is
- /// stored in the C flag of the CPSR.
+ /// stored in the C (signed) or V (unsigned) flag of the CPSR.
///
/// This MCValue is only generated by a add_with_overflow or
- /// sub_with_overflow instruction operating on u32.
- register_c_flag: Register,
- /// The value is a tuple { wrapped: i32, overflow: u1 } where
- /// wrapped is stored in the register and the overflow bit is
- /// stored in the V flag of the CPSR.
- ///
- /// This MCValue is only generated by a add_with_overflow or
- /// sub_with_overflow instruction operating on i32.
- register_v_flag: Register,
+ /// sub_with_overflow instruction operating on 32- or 64-bit values.
+ register_with_overflow: struct { reg: Register, flag: bits.Instruction.Condition },
/// The value is in memory at a hard-coded address.
///
/// If the type is a pointer, it means the pointer address is at
@@ -760,10 +753,8 @@ fn processDeath(self: *Self, inst: Air.Inst.Index) void {
.register => |reg| {
self.register_manager.freeReg(reg);
},
- .register_c_flag,
- .register_v_flag,
- => |reg| {
- self.register_manager.freeReg(reg);
+ .register_with_overflow => |rwo| {
+ self.register_manager.freeReg(rwo.reg);
self.compare_flags_inst = null;
},
.compare_flags_signed, .compare_flags_unsigned => {
@@ -905,10 +896,8 @@ pub fn spillInstruction(self: *Self, reg: Register, inst: Air.Inst.Index) !void
log.debug("spilling {d} to stack mcv {any}", .{ inst, stack_mcv });
const reg_mcv = self.getResolvedInstValue(inst);
switch (reg_mcv) {
- .register,
- .register_c_flag,
- .register_v_flag,
- => |r| assert(reg.id() == r.id()),
+ .register => |r| assert(reg.id() == r.id()),
+ .register_with_overflow => |rwo| assert(rwo.reg.id() == reg.id()),
else => unreachable, // not a register
}
const branch = &self.branch_stack.items[self.branch_stack.items.len - 1];
@@ -925,9 +914,7 @@ fn spillCompareFlagsIfOccupied(self: *Self) !void {
.compare_flags_signed,
.compare_flags_unsigned,
=> try self.allocRegOrMem(inst_to_save, true),
- .register_c_flag,
- .register_v_flag,
- => try self.allocRegOrMem(inst_to_save, false),
+ .register_with_overflow => try self.allocRegOrMem(inst_to_save, false),
else => unreachable, // mcv doesn't occupy the compare flags
};
@@ -942,9 +929,7 @@ fn spillCompareFlagsIfOccupied(self: *Self) !void {
// TODO consolidate with register manager and spillInstruction
// this call should really belong in the register manager!
switch (mcv) {
- .register_c_flag,
- .register_v_flag,
- => |reg| self.register_manager.freeReg(reg),
+ .register_with_overflow => |rwo| self.register_manager.freeReg(rwo.reg),
else => {},
}
}
@@ -1932,14 +1917,18 @@ fn airOverflow(self: *Self, inst: Air.Inst.Index) !void {
}
};
- if (tag == .sub_with_overflow) {
- break :result MCValue{ .register_v_flag = dest.register };
- }
-
- switch (int_info.signedness) {
- .unsigned => break :result MCValue{ .register_c_flag = dest.register },
- .signed => break :result MCValue{ .register_v_flag = dest.register },
- }
+ const flag: bits.Instruction.Condition = switch (int_info.signedness) {
+ .unsigned => switch (tag) {
+ .add_with_overflow => bits.Instruction.Condition.cs,
+ .sub_with_overflow => bits.Instruction.Condition.cc,
+ else => unreachable,
+ },
+ .signed => .vs,
+ };
+ break :result MCValue{ .register_with_overflow = .{
+ .reg = dest.register,
+ .flag = flag,
+ } };
},
else => return self.fail("TODO overflow operations on integers > u32/i32", .{}),
}
@@ -2648,8 +2637,7 @@ fn load(self: *Self, dst_mcv: MCValue, ptr: MCValue, ptr_ty: Type) InnerError!vo
.dead => unreachable,
.compare_flags_unsigned,
.compare_flags_signed,
- .register_c_flag,
- .register_v_flag,
+ .register_with_overflow,
=> unreachable, // cannot hold an address
.immediate => |imm| try self.setRegOrMem(elem_ty, dst_mcv, .{ .memory = imm }),
.ptr_stack_offset => |off| try self.setRegOrMem(elem_ty, dst_mcv, .{ .stack_offset = off }),
@@ -2871,8 +2859,7 @@ fn store(self: *Self, ptr: MCValue, value: MCValue, ptr_ty: Type, value_ty: Type
.dead => unreachable,
.compare_flags_unsigned,
.compare_flags_signed,
- .register_c_flag,
- .register_v_flag,
+ .register_with_overflow,
=> unreachable, // cannot hold an address
.immediate => |imm| {
try self.setRegOrMem(value_ty, .{ .memory = imm }, value);
@@ -2993,13 +2980,11 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
.memory => |addr| {
break :result MCValue{ .memory = addr + struct_field_offset };
},
- .register_c_flag,
- .register_v_flag,
- => |reg| {
+ .register_with_overflow => |rwo| {
switch (index) {
0 => {
// get wrapped value: return register
- break :result MCValue{ .register = reg };
+ break :result MCValue{ .register = rwo.reg };
},
1 => {
// TODO return special MCValue condition flags
@@ -3008,17 +2993,11 @@ fn airStructFieldVal(self: *Self, inst: Air.Inst.Index) !void {
const raw_dest_reg = try self.register_manager.allocReg(null, gp);
const dest_reg = raw_dest_reg.to32();
- // C flag: cset reg, cs
- // V flag: cset reg, vs
_ = try self.addInst(.{
.tag = .cset,
.data = .{ .r_cond = .{
.rd = dest_reg,
- .cond = switch (mcv) {
- .register_c_flag => .cs,
- .register_v_flag => .vs,
- else => unreachable,
- },
+ .cond = rwo.flag,
} },
});
@@ -4073,14 +4052,12 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
else => return self.fail("TODO implement storing other types abi_size={}", .{abi_size}),
}
},
- .register_c_flag,
- .register_v_flag,
- => |reg| {
- const reg_lock = self.register_manager.lockReg(reg);
+ .register_with_overflow => |rwo| {
+ const reg_lock = self.register_manager.lockReg(rwo.reg);
defer if (reg_lock) |locked_reg| self.register_manager.unlockReg(locked_reg);
const wrapped_ty = ty.structFieldType(0);
- try self.genSetStack(wrapped_ty, stack_offset, .{ .register = reg });
+ try self.genSetStack(wrapped_ty, stack_offset, .{ .register = rwo.reg });
const overflow_bit_ty = ty.structFieldType(1);
const overflow_bit_offset = @intCast(u32, ty.structFieldOffset(1, self.target.*));
@@ -4090,17 +4067,11 @@ fn genSetStack(self: *Self, ty: Type, stack_offset: u32, mcv: MCValue) InnerErro
@intCast(u32, overflow_bit_ty.abiSize(self.target.*)),
);
- // C flag: cset reg, cs
- // V flag: cset reg, vs
_ = try self.addInst(.{
.tag = .cset,
.data = .{ .r_cond = .{
.rd = cond_reg,
- .cond = switch (mcv) {
- .register_c_flag => .cs,
- .register_v_flag => .vs,
- else => unreachable,
- },
+ .cond = rwo.flag,
} },
});
@@ -4270,9 +4241,7 @@ fn genSetReg(self: *Self, ty: Type, reg: Register, mcv: MCValue) InnerError!void
.data = .{ .rr = .{ .rd = reg, .rn = src_reg } },
});
},
- .register_c_flag,
- .register_v_flag,
- => unreachable, // doesn't fit into a register
+ .register_with_overflow => unreachable, // doesn't fit into a register
.got_load,
.direct_load,
=> |sym_index| {