[llvm] [GlobalIsel] Use aext in ctlz_zero_undef expansion (PR #181506)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-globalisel

Author: Alex MacLean (AlexMaclean)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/181506.diff


1 Files Affected:

- (modified) llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp (+1) 


``````````diff
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 41b79ccb4e4d1..ffd0814f86010 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -2816,6 +2816,7 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
     switch (Opcode) {
     case TargetOpcode::G_CTTZ:
     case TargetOpcode::G_CTTZ_ZERO_UNDEF:
+    case TargetOpcode::G_CTLZ_ZERO_UNDEF: // undef bits shifted out below
       ExtOpc = TargetOpcode::G_ANYEXT;
       break;
     case TargetOpcode::G_CTLS:

``````````

</details>


https://github.com/llvm/llvm-project/pull/181506