zig

commit 4e357151a54c9a2f373cef59e2718a61cfbe3658 (tree)
parent 961248cde32e0d572225c6c1d367b960540ae220
Author: William Sengir <william@sengir.com>
Date:   Sun, 20 Mar 2022 00:00:13 -0700

stage2: align store for vector-to-array bitcast in LLVM backend

This was causing a very rare segfault when LLVM would emit `vmovdqa`
using an unaligned memory operand on the stack.

Diffstat:
M
src/codegen/llvm.zig
 | 
3
++-

1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
@@ -5563,7 +5563,8 @@ pub const FuncGen = struct {
             if (bitcast_ok) {
                 const llvm_vector_ty = try self.dg.llvmType(operand_ty);
                 const casted_ptr = self.builder.buildBitCast(array_ptr, llvm_vector_ty.pointerType(0), "");
-                _ = self.builder.buildStore(operand, casted_ptr);
+                const llvm_store = self.builder.buildStore(operand, casted_ptr);
+                llvm_store.setAlignment(inst_ty.abiAlignment(target));
             } else {
                 // If the ABI size of the element type is not evenly divisible by size in bits;
                 // a simple bitcast will not work, and we fall back to extractelement.