Vendor import of llvm-project branch release/12.x llvmorg-12.0.1-rc2-0-ge7dac564cd0e, a.k.a. 12.0.1 rc2.llvmorg-12.0.1-rc2-0-ge7dac564cd0e

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index c40e5c36cdc7..a12816885c40 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4127,10 +4127,12 @@ static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
                                               TrueVal, FalseVal))
     return V;
 
-  // If we have an equality comparison, then we know the value in one of the
-  // arms of the select. See if substituting this value into the arm and
+  // If we have a scalar equality comparison, then we know the value in one of
+  // the arms of the select. See if substituting this value into the arm and
   // simplifying the result yields the same value as the other arm.
-  if (Pred == ICmpInst::ICMP_EQ) {
+  // Note that the equivalence/replacement opportunity does not hold for vectors
+  // because each element of a vector select is chosen independently.
+  if (Pred == ICmpInst::ICMP_EQ && !CondVal->getType()->isVectorTy()) {
     if (SimplifyWithOpReplaced(FalseVal, CmpLHS, CmpRHS, Q,
                                /* AllowRefinement */ false, MaxRecurse) ==
             TrueVal ||