fix PR6195, a bug constant folding scalar -> vector compares.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94997 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 3 deletions

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index 5e4b472097..d537b27376 100644
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -2017,10 +2017,12 @@ Constant *llvm::ConstantFoldCompareInstruction(LLVMContext &Context,
       return ConstantInt::get(Type::getInt1Ty(Context), Result);
 
     // If the right hand side is a bitcast, try using its inverse to simplify
-    // it by moving it to the left hand side.
+    // it by moving it to the left hand side.  We can't do this if it would turn
+    // a vector compare into scalar compare of visa versa.
     if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(C2)) {
-      if (CE2->getOpcode() == Instruction::BitCast) {
-        Constant *CE2Op0 = CE2->getOperand(0);
+      Constant *CE2Op0 = CE2->getOperand(0);
+      if (CE2->getOpcode() == Instruction::BitCast &&
+          isa<VectorType>(CE2->getType()) ==isa<VectorType>(CE2Op0->getType())){
         Constant *Inverse = ConstantExpr::getBitCast(C1, CE2Op0->getType());
         return ConstantExpr::getICmp(pred, Inverse, CE2Op0);
       }
diff --git a/test/Transforms/InstCombine/icmp.ll b/test/Transforms/InstCombine/icmp.ll
index 79fa220752..c2234a10e5 100644
--- a/test/Transforms/InstCombine/icmp.ll
+++ b/test/Transforms/InstCombine/icmp.ll
@@ -112,3 +112,12 @@ define i1 @test11(i32 %x) {
 ; CHECK: ret i1 true
 }
 
+; PR6195
+define i1 @test12(i1 %A) {
+  %S = select i1 %A, i64 -4294967295, i64 8589934591
+  %B = icmp ne i64 bitcast (<2 x i32> <i32 1, i32 -1> to i64), %S
+  ret i1 %B
+; CHECK: @test12
+; CHECK-NEXT: %B = select i1
+; CHECK-NEXT: ret i1 %B
+}