[llvm] r298118 - [x86] clean up setcc with negated operand transform and add missing test; NFCI

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Fri Mar 17 15:29:40 2017
New Revision: 298118

URL: http://llvm.org/viewvc/llvm-project?rev=298118&view=rev
Log:
[x86] clean up setcc with negated operand transform and add missing test; NFCI

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/neg_cmp.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=298118&r1=298117&r2=298118&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Mar 17 15:29:40 2017
@@ -33954,8 +33954,6 @@ static SDValue combineZext(SDNode *N, Se
   return SDValue();
 }
 
-/// Optimize x == -y --> x+y == 0
-///          x != -y --> x+y != 0
 static SDValue combineSetCC(SDNode *N, SelectionDAG &DAG,
                             const X86Subtarget &Subtarget) {
   ISD::CondCode CC = cast<CondCodeSDNode>(N->getOperand(2))->get();
@@ -33964,20 +33962,23 @@ static SDValue combineSetCC(SDNode *N, S
   EVT VT = N->getValueType(0);
   SDLoc DL(N);
 
-  if ((CC == ISD::SETNE || CC == ISD::SETEQ) && LHS.getOpcode() == ISD::SUB)
-    if (isNullConstant(LHS.getOperand(0)) && LHS.hasOneUse()) {
-      SDValue addV = DAG.getNode(ISD::ADD, DL, LHS.getValueType(), RHS,
-                                 LHS.getOperand(1));
-      return DAG.getSetCC(DL, N->getValueType(0), addV,
-                          DAG.getConstant(0, DL, addV.getValueType()), CC);
+  if (CC == ISD::SETNE || CC == ISD::SETEQ) {
+    EVT OpVT = LHS.getValueType();
+    // 0-x == y --> x+y == 0
+    // 0-x != y --> x+y != 0
+    if (LHS.getOpcode() == ISD::SUB && isNullConstant(LHS.getOperand(0)) &&
+        LHS.hasOneUse()) {
+      SDValue Add = DAG.getNode(ISD::ADD, DL, OpVT, RHS, LHS.getOperand(1));
+      return DAG.getSetCC(DL, VT, Add, DAG.getConstant(0, DL, OpVT), CC);
     }
-  if ((CC == ISD::SETNE || CC == ISD::SETEQ) && RHS.getOpcode() == ISD::SUB)
-    if (isNullConstant(RHS.getOperand(0)) && RHS.hasOneUse()) {
-      SDValue addV = DAG.getNode(ISD::ADD, DL, RHS.getValueType(), LHS,
-                                 RHS.getOperand(1));
-      return DAG.getSetCC(DL, N->getValueType(0), addV,
-                          DAG.getConstant(0, DL, addV.getValueType()), CC);
+    // x == 0-y --> x+y == 0
+    // x != 0-y --> x+y != 0
+    if (RHS.getOpcode() == ISD::SUB && isNullConstant(RHS.getOperand(0)) &&
+        RHS.hasOneUse()) {
+      SDValue Add = DAG.getNode(ISD::ADD, DL, OpVT, LHS, RHS.getOperand(1));
+      return DAG.getSetCC(DL, VT, Add, DAG.getConstant(0, DL, OpVT), CC);
     }
+  }
 
   if (VT.getScalarType() == MVT::i1 &&
       (CC == ISD::SETNE || CC == ISD::SETEQ || ISD::isSignedIntSetCC(CC))) {

Modified: llvm/trunk/test/CodeGen/X86/neg_cmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/neg_cmp.ll?rev=298118&r1=298117&r2=298118&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/neg_cmp.ll (original)
+++ llvm/trunk/test/CodeGen/X86/neg_cmp.ll Fri Mar 17 15:29:40 2017
@@ -1,22 +1,50 @@
-; RUN: llc < %s -march=x86-64 | FileCheck %s
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown | FileCheck %s
 
 ; rdar://11245199
 ; PR12545
-define void @f(i32 %x, i32 %y) nounwind uwtable ssp {
-entry:
-; CHECK-LABEL: f:
-; CHECK-NOT: neg
-; CHECK: add
+
+declare void @g()
+
+define void @neg_cmp(i32 %x, i32 %y) nounwind {
+; CHECK-LABEL: neg_cmp:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    addl %esi, %edi
+; CHECK-NEXT:    jne .LBB0_1
+; CHECK-NEXT:  # BB#2: # %if.then
+; CHECK-NEXT:    jmp g # TAILCALL
+; CHECK-NEXT:  .LBB0_1: # %if.end
+; CHECK-NEXT:    retq
   %sub = sub i32 0, %y
   %cmp = icmp eq i32 %x, %sub
   br i1 %cmp, label %if.then, label %if.end
 
-if.then:                                          ; preds = %entry
+if.then:
   tail call void @g() nounwind
   br label %if.end
 
-if.end:                                           ; preds = %if.then, %entry
+if.end:
+  ret void
+}
+
+define void @neg_cmp_commuted(i32 %x, i32 %y) nounwind {
+; CHECK-LABEL: neg_cmp_commuted:
+; CHECK:       # BB#0:
+; CHECK-NEXT:    addl %esi, %edi
+; CHECK-NEXT:    jne .LBB1_1
+; CHECK-NEXT:  # BB#2: # %if.then
+; CHECK-NEXT:    jmp g # TAILCALL
+; CHECK-NEXT:  .LBB1_1: # %if.end
+; CHECK-NEXT:    retq
+  %sub = sub i32 0, %y
+  %cmp = icmp eq i32 %sub, %x
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+  tail call void @g() nounwind
+  br label %if.end
+
+if.end:
   ret void
 }
 
-declare void @g()