X86: Don't turn shifts into ands if there's another use that may not check for equality.

Fixes PR19964.

llvm-svn: 210371

2 files changed, 14 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 9e728c7f7a9..24cc828aca1 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -10162,7 +10162,7 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, SDLoc dl,
     // If we have a constant logical shift that's only used in a comparison
     // against zero turn it into an equivalent AND. This allows turning it into
     // a TEST instruction later.
-    if ((X86CC == X86::COND_E || X86CC == X86::COND_NE) &&
+    if ((X86CC == X86::COND_E || X86CC == X86::COND_NE) && Op->hasOneUse() &&
         isa<ConstantSDNode>(Op->getOperand(1)) && !hasNonFlagsUse(Op)) {
       EVT VT = Op.getValueType();
       unsigned BitWidth = VT.getSizeInBits();
diff --git a/llvm/test/CodeGen/X86/cmp.ll b/llvm/test/CodeGen/X86/cmp.ll
index cdcdc963ed1..149d53759fe 100644
--- a/llvm/test/CodeGen/X86/cmp.ll
+++ b/llvm/test/CodeGen/X86/cmp.ll
@@ -198,3 +198,16 @@ define i32 @test14(i32 %mask, i32 %base, i32 %intra) #0 {
 ; CHECK: 	shrl	$7, %edi
 ; CHECK-NEXT: 	cmovnsl	%edx, %esi
 }
+
+; PR19964
+define zeroext i1 @test15(i32 %bf.load, i32 %n) {
+  %bf.lshr = lshr i32 %bf.load, 16
+  %cmp2 = icmp eq i32 %bf.lshr, 0
+  %cmp5 = icmp uge i32 %bf.lshr, %n
+  %.cmp5 = or i1 %cmp2, %cmp5
+  ret i1 %.cmp5
+
+; CHECK-LABEL: test15:
+; CHECK:  shrl	$16, %edi
+; CHECK:  cmpl	%esi, %edi
+}