[GVN] Disable GVN PRE on target hasBranchDivergence

[fengfeng09]

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[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: fengfeng (fengfeng09)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/77069.diff

1 Files Affected:

• (modified) llvm/lib/Transforms/Scalar/GVN.cpp (+5)

diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index e36578f3de7ac4..777dec04faf9f6 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -41,6 +41,7 @@
 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
 #include "llvm/Analysis/PHITransAddr.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
@@ -750,6 +751,10 @@ bool GVNPass::isMemDepEnabled() const {
 }
 
 PreservedAnalyses GVNPass::run(Function &F, FunctionAnalysisManager &AM) {
+  // Disable PRE on GPU.
+  auto &TTI = AM.getResult<TargetIRAnalysis>(F);
+  if (TTI.hasBranchDivergence())
+    GVNEnablePRE = false;
   // FIXME: The order of evaluation of these 'getResult' calls is very
   // significant! Re-ordering these variables will cause GVN when run alone to
   // be less effective! We should fix memdep and basic-aa to not exhibit this