Revert "Reapply "[LV] Improve AnyOf reduction codegen. (#78304)""

This reverts commit c6e38b928c56f562aea68a8e90f02dbdf0eada85.

Causes miscompiles, see comments on #78304.

1 files changed, 18 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
index 9d816c5..73c5d63 100644
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -1034,6 +1034,15 @@ CmpInst::Predicate llvm::getMinMaxReductionPredicate(RecurKind RK) {
   }
 }
 
+Value *llvm::createAnyOfOp(IRBuilderBase &Builder, Value *StartVal,
+                           RecurKind RK, Value *Left, Value *Right) {
+  if (auto VTy = dyn_cast<VectorType>(Left->getType()))
+    StartVal = Builder.CreateVectorSplat(VTy->getElementCount(), StartVal);
+  Value *Cmp =
+      Builder.CreateCmp(CmpInst::ICMP_NE, Left, StartVal, "rdx.select.cmp");
+  return Builder.CreateSelect(Cmp, Left, Right, "rdx.select");
+}
+
 Value *llvm::createMinMaxOp(IRBuilderBase &Builder, RecurKind RK, Value *Left,
                             Value *Right) {
   Type *Ty = Left->getType();
@@ -1142,13 +1151,16 @@ Value *llvm::createAnyOfTargetReduction(IRBuilderBase &Builder, Value *Src,
     NewVal = SI->getTrueValue();
   }
 
+  // Create a splat vector with the new value and compare this to the vector
+  // we want to reduce.
+  ElementCount EC = cast<VectorType>(Src->getType())->getElementCount();
+  Value *Right = Builder.CreateVectorSplat(EC, InitVal);
+  Value *Cmp =
+      Builder.CreateCmp(CmpInst::ICMP_NE, Src, Right, "rdx.select.cmp");
+
   // If any predicate is true it means that we want to select the new value.
-  Value *AnyOf =
-      Src->getType()->isVectorTy() ? Builder.CreateOrReduce(Src) : Src;
-  // The compares in the loop may yield poison, which propagates through the
-  // bitwise ORs. Freeze it here before the condition is used.
-  AnyOf = Builder.CreateFreeze(AnyOf);
-  return Builder.CreateSelect(AnyOf, NewVal, InitVal, "rdx.select");
+  Cmp = Builder.CreateOrReduce(Cmp);
+  return Builder.CreateSelect(Cmp, NewVal, InitVal, "rdx.select");
 }
 
 Value *llvm::createSimpleTargetReduction(IRBuilderBase &Builder, Value *Src,