[llvm] Added ROLW/RORW/SLLW/SRAW/SRLW for canCreateUndefOrPoisonForTargetNode (PR #152609)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-risc-v

Author: Jasmine Tang (badumbatish)

<details>
<summary>Changes</summary>

Fixes https://github.com/llvm/llvm-project/issues/149285.



---
Full diff: https://github.com/llvm/llvm-project/pull/152609.diff


1 Files Affected:

- (modified) llvm/lib/Target/RISCV/RISCVISelLowering.cpp (+8) 


``````````diff
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index adbfbeb4669e7..d86ec003459d3 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -21477,6 +21477,14 @@ bool RISCVTargetLowering::canCreateUndefOrPoisonForTargetNode(
 
   // TODO: Add more target nodes.
   switch (Op.getOpcode()) {
+  case RISCVISD::SLLW:
+  case RISCVISD::SRAW:
+  case RISCVISD::SRLW:
+  case RISCVISD::RORW:
+  case RISCVISD::ROLW:
+    // Only the lower 5 bits of RHS are read, guaranteeing the rotate/shift
+    // amount is bounds.
+    return false;
   case RISCVISD::SELECT_CC:
     // Integer select_cc cannot create poison.
     // TODO: What are the FP poison semantics?

``````````

</details>


https://github.com/llvm/llvm-project/pull/152609