LLVM: insert workaround for aarch64-windows f16 CodeView crash

1 files changed, 20 insertions, 0 deletions

diff --git a/src/codegen/llvm.zig b/src/codegen/llvm.zig
index 63e7eece99..d11a359bb6 100644
--- a/src/codegen/llvm.zig
+++ b/src/codegen/llvm.zig
@@ -4577,6 +4577,10 @@ pub const FuncGen = struct {
         const operand_ty = self.air.typeOf(pl_op.operand);
         const name = self.air.nullTerminatedString(pl_op.payload);
 
+        if (needDbgVarWorkaround(self.dg, operand_ty)) {
+            return null;
+        }
+
         const di_local_var = dib.createAutoVariable(
             self.di_scope.?,
             name.ptr,
@@ -6147,6 +6151,10 @@ pub const FuncGen = struct {
 
         const inst_ty = self.air.typeOfIndex(inst);
         if (self.dg.object.di_builder) |dib| {
+            if (needDbgVarWorkaround(self.dg, inst_ty)) {
+                return arg_val;
+            }
+
             const src_index = self.getSrcArgIndex(self.arg_index - 1);
             const func = self.dg.decl.getFunction().?;
             const lbrace_line = self.dg.module.declPtr(func.owner_decl).src_line + func.lbrace_line + 1;
@@ -8248,3 +8256,15 @@ const AnnotatedDITypePtr = enum(usize) {
 };
 
 const lt_errors_fn_name = "__zig_lt_errors_len";
+
+/// Without this workaround, LLVM crashes with "unknown codeview register H1"
+/// TODO use llvm-reduce and file upstream LLVM bug for this.
+fn needDbgVarWorkaround(dg: *DeclGen, ty: Type) bool {
+    if (ty.tag() == .f16) {
+        const target = dg.module.getTarget();
+        if (target.os.tag == .windows and target.cpu.arch == .aarch64) {
+            return true;
+        }
+    }
+    return false;
+}