[X86] Remove unused node after morphing it from shr to and.

In some cases it won't get cleaned up properly leading to crashes
downstream. PR23353.

Based on a patch by Davide Italiano.

llvm-svn: 237828

2 files changed, 18 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 964a599e881..5b99adcb1bd 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -12737,6 +12737,7 @@ SDValue X86TargetLowering::EmitTest(SDValue Op, unsigned X86CC, SDLoc dl,
       SDValue New = DAG.getNode(ISD::AND, dl, VT, Op->getOperand(0),
                                 DAG.getConstant(Mask, dl, VT));
       DAG.ReplaceAllUsesWith(Op, New);
+      DAG.RemoveDeadNode(Op.getNode());
       Op = New;
     }
     break;
diff --git a/llvm/test/CodeGen/X86/cmp.ll b/llvm/test/CodeGen/X86/cmp.ll
index 584179aacbc..fec47ec9380 100644
--- a/llvm/test/CodeGen/X86/cmp.ll
+++ b/llvm/test/CodeGen/X86/cmp.ll
@@ -211,3 +211,20 @@ define zeroext i1 @test15(i32 %bf.load, i32 %n) {
 ; CHECK:  shrl	$16, %edi
 ; CHECK:  cmpl	%esi, %edi
 }
+
+; PR23353
+define i1 @test16(i32* %a, i1* %b) {
+  %load = load i32, i32* %a
+  %trunc = trunc i32 %load to i8
+  %mul = mul i8 %trunc, 2
+  %icmp1 = icmp ne i8 %mul, 0
+  store i1 %icmp1, i1* %b
+  %and = and i8 %trunc, 127
+  %icmp2 = icmp ne i8 %and, 0
+  ret i1 %icmp2
+
+; CHECK-LABEL: test16:
+; CHECK-NOT: addb
+; CHECK-NOT: andb
+; CHECK: testb $127
+}