[llvm] [X86] Clear regcall arg aliases in dynamic CSR masks (PR #225262)

[Phoebe Wang via llvm-commits]

================
@@ -0,0 +1,38 @@
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -O2 -stop-after=finalize-isel | FileCheck %s
+
+; When an x86_regcall argument or return value uses a 32-bit subregister (such
+; as R14D), the dynamic call-preserved mask must clear all aliases including the
+; 64-bit superregister (R14). Otherwise a live value in the superregister can be
+; incorrectly assumed preserved across the call.
+;
+; Fixes llvm/llvm-project#225057.
----------------
phoebewang wrote:

You can rename the test to pr225057 and remove the comment.

https://github.com/llvm/llvm-project/pull/225262