1 files changed, 10 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index f94a65a75f0..221a2200717 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -1042,12 +1042,16 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
   if (Value *V = SimplifyUsingDistributiveLaws(I))
     return replaceInstUsesWith(I, V);
 
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+  const APInt *Val;
+  if (match(RHS, m_APInt(Val))) {
     // X + (signbit) --> X ^ signbit
-    const APInt &Val = CI->getValue();
-    if (Val.isSignBit())
+    if (Val->isSignBit())
       return BinaryOperator::CreateXor(LHS, RHS);
+  }
 
+  // FIXME: Use the match above instead of dyn_cast to allow these transforms
+  // for splat vectors.
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
     // See if SimplifyDemandedBits can simplify this.  This handles stuff like
     // (X & 254)+1 -> (X&254)|1
     if (SimplifyDemandedInstructionBits(I))
@@ -1149,6 +1153,9 @@ Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
       return BinaryOperator::CreateSub(SubOne(CRHS), X);
   }
 
+  // FIXME: We already did a check for ConstantInt RHS above this.
+  // FIXME: Is this pattern covered by another fold? No regression tests fail on
+  // removal.
   if (ConstantInt *CRHS = dyn_cast<ConstantInt>(RHS)) {
     // (X & FF00) + xx00  -> (X+xx00) & FF00
     Value *X;