[llvm-branch-commits] [llvm] IROutliner: Do not look at use lists of constant phi inputs (PR #135019)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

Theoretically this does a worse job with globals but this is not
covered by existing tests

---
Full diff: https://github.com/llvm/llvm-project/pull/135019.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/IPO/IROutliner.cpp (+2-1) 


``````````diff
diff --git a/llvm/lib/Transforms/IPO/IROutliner.cpp b/llvm/lib/Transforms/IPO/IROutliner.cpp
index 8c5946fb07c65..eec869d57a6db 100644
--- a/llvm/lib/Transforms/IPO/IROutliner.cpp
+++ b/llvm/lib/Transforms/IPO/IROutliner.cpp
@@ -1126,7 +1126,8 @@ static void analyzeExitPHIsForOutputUses(
     // outside of the single PHINode we should not skip over it.
     for (unsigned Idx : IncomingVals) {
       Value *V = PN.getIncomingValue(Idx);
-      if (outputHasNonPHI(V, Idx, PN, PotentialExitsFromRegion, RegionBlocks)) {
+      if (!isa<Constant>(V) &&
+          outputHasNonPHI(V, Idx, PN, PotentialExitsFromRegion, RegionBlocks)) {
         OutputsWithNonPhiUses.insert(V);
         OutputsReplacedByPHINode.erase(V);
         continue;

``````````

</details>


https://github.com/llvm/llvm-project/pull/135019