[llvm-branch-commits] [llvm] [InstCombine] Enable select freeze poison folding when storing value (PR #129776)

[Yingwei Zheng via llvm-branch-commits]

================
@@ -4813,15 +4813,22 @@ Instruction *InstCombinerImpl::visitFreeze(FreezeInst 
&I) {
   // TODO: This could use getBinopAbsorber() / getBinopIdentity() to avoid
   //       duplicating logic for binops at least.
   auto getUndefReplacement = [&I](Type *Ty) {
-    Constant *BestValue = nullptr;
-    Constant *NullValue = Constant::getNullValue(Ty);
+    Value *BestValue = nullptr;
+    Value *NullValue = Constant::getNullValue(Ty);
     for (const auto *U : I.users()) {
-      Constant *C = NullValue;
+      Value *C = NullValue;
       if (match(U, m_Or(m_Value(), m_Value())))
         C = ConstantInt::getAllOnesValue(Ty);
       else if (match(U, m_Select(m_Specific(&I), m_Constant(), m_Value())))
         C = ConstantInt::getTrue(Ty);
-
+      else if (I.hasOneUse() &&
----------------
dtcxzyw wrote:

If `I` has only one use, it must have only one user. I would like to hoist this 
logic out of the loop.
```
if (I.hasOneUse() && match(I->user_back(), m_c_Select(m_Specific(&I), 
m_Value(Arm)) && isGuaranteedNotToBeUndefOrPoison(Arm, &AC, &DT, &I))
  return Arm;

// existing code
Constant *BestValue = nullptr;
Constant *NullValue = Constant::getNullValue(Ty);
...
```


https://github.com/llvm/llvm-project/pull/129776
_______________________________________________
llvm-branch-commits mailing list
llvm-branch-commits@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits