InstCombine: Allow folding of xor into icmp by changing the predicate for vectors

The loop vectorizer can create this pattern.

llvm-svn: 228954

2 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index c65441e1c85..6178d9c73a1 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -2604,15 +2604,16 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
     }
   }
 
-
-  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
-    if (RHS->isOne() && Op0->hasOneUse())
+  if (Constant *RHS = dyn_cast<Constant>(Op1)) {
+    if (RHS->isAllOnesValue() && Op0->hasOneUse())
       // xor (cmp A, B), true = not (cmp A, B) = !cmp A, B
       if (CmpInst *CI = dyn_cast<CmpInst>(Op0))
         return CmpInst::Create(CI->getOpcode(),
                                CI->getInversePredicate(),
                                CI->getOperand(0), CI->getOperand(1));
+  }
 
+  if (ConstantInt *RHS = dyn_cast<ConstantInt>(Op1)) {
     // fold (xor(zext(cmp)), 1) and (xor(sext(cmp)), -1) to ext(!cmp).
     if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
       if (CmpInst *CI = dyn_cast<CmpInst>(Op0C->getOperand(0))) {
diff --git a/llvm/test/Transforms/InstCombine/not.ll b/llvm/test/Transforms/InstCombine/not.ll
index 4012ce1ea4b..9d59edd7934 100644
--- a/llvm/test/Transforms/InstCombine/not.ll
+++ b/llvm/test/Transforms/InstCombine/not.ll
@@ -52,3 +52,9 @@ entry:
 	%retval67 = zext i1 %tmp3 to i8		; <i8> [#uses=1]
 	ret i8 %retval67
 }
+
+define <2 x i1> @test7(<2 x i32> %A, <2 x i32> %B) {
+        %cond = icmp sle <2 x i32> %A, %B
+        %Ret = xor <2 x i1> %cond, <i1 true, i1 true>
+        ret <2 x i1> %Ret
+}