Fix combine of uno && ord -> false so that the ordering of the fcmps doesn't

matter.
rdar://11579835

llvm-svn: 158084

2 files changed, 13 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 0f10d7376c3..3bafc6661b0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -986,6 +986,9 @@ Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
     bool Op1Ordered;
     unsigned Op0Pred = getFCmpCode(Op0CC, Op0Ordered);
     unsigned Op1Pred = getFCmpCode(Op1CC, Op1Ordered);
+    // uno && ord -> false
+    if (Op0Pred == 0 && Op1Pred == 0 && Op0Ordered != Op1Ordered)
+        return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
     if (Op1Pred == 0) {
       std::swap(LHS, RHS);
       std::swap(Op0Pred, Op1Pred);
@@ -998,7 +1001,6 @@ Value *InstCombiner::FoldAndOfFCmps(FCmpInst *LHS, FCmpInst *RHS) {
         return RHS;
       
       // uno && oeq -> uno && (ord && eq) -> false
-      // uno && ord -> false
       if (!Op0Ordered)
         return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
       // ord && ueq -> ord && (uno || eq) -> oeq
diff --git a/llvm/test/Transforms/InstCombine/and-fcmp.ll b/llvm/test/Transforms/InstCombine/and-fcmp.ll
index f6a226e3b58..282e88b53d0 100644
--- a/llvm/test/Transforms/InstCombine/and-fcmp.ll
+++ b/llvm/test/Transforms/InstCombine/and-fcmp.ll
@@ -56,3 +56,13 @@ define zeroext i8 @t5(float %x, float %y) nounwind {
 ; CHECK: t5
 ; CHECK: ret i8 0
 }
+
+define zeroext i8 @t6(float %x, float %y) nounwind {
+       %a = fcmp uno float %x, %y
+       %b = fcmp ord float %x, %y
+       %c = and i1 %a, %b
+       %retval = zext i1 %c to i8
+       ret i8 %retval
+; CHECK: t6
+; CHECK: ret i8 0
+}