Commit d7d2ccb7af

John Schmidt <john.schmidt.h@gmail.com>
2022-03-17 22:29:39
Avoid index out of bounds for one-valued types in zirValidateArrayInit
Previously, the code assumed that `ptr_elem_ptr` was always followed by a `store`, but this is not true for types with one value (such as `u0`).
master
1 parent adfcc88
Changed files (2)
src
Sema.zig
test
behavior
byteswap.zig
src/Sema.zig
@@ -3205,14 +3205,11 @@ fn zirValidateArrayInit(
         // instruction after it within the same block.
         // Possible performance enhancement: save the `block_index` between iterations
         // of the for loop.
-        const next_air_inst = inst: {
-            var block_index = block.instructions.items.len - 1;
-            while (block.instructions.items[block_index] != elem_ptr_air_inst) {
-                block_index -= 1;
-            }
-            first_block_index = @minimum(first_block_index, block_index);
-            break :inst block.instructions.items[block_index + 1];
-        };
+        var block_index = block.instructions.items.len - 1;
+        while (block.instructions.items[block_index] != elem_ptr_air_inst) {
+            block_index -= 1;
+        }
+        first_block_index = @minimum(first_block_index, block_index);
 
         // Array has one possible value, so value is always comptime-known
         if (opt_opv) |opv| {
@@ -3222,6 +3219,7 @@ fn zirValidateArrayInit(
 
         // If the next instructon is a store with a comptime operand, this element
         // is comptime.
+        const next_air_inst = block.instructions.items[block_index + 1];
         switch (air_tags[next_air_inst]) {
             .store => {
                 const bin_op = air_datas[next_air_inst].bin_op;
test/behavior/byteswap.zig
@@ -114,9 +114,6 @@ fn vector0() !void {
 }
 
 test "@byteSwap vectors u0" {
-    // TODO: vector initialization for @Vector(x, u0) currently fails.
-    if (builtin.zig_backend == .stage2_llvm) return error.SkipZigTest;
-
     if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_c) return error.SkipZigTest;
     if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest;