[llvm] 96bb076 - [TargetLowering] Move the setBooleanContents check on (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc) to the right place

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2019-11-01T14:43:17-07:00
New Revision: 96bb07662104f175c354ffaa2d58a8f6bb984249

URL: https://github.com/llvm/llvm-project/commit/96bb07662104f175c354ffaa2d58a8f6bb984249
DIFF: https://github.com/llvm/llvm-project/commit/96bb07662104f175c354ffaa2d58a8f6bb984249.diff

LOG: [TargetLowering] Move the setBooleanContents check on (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc) to the right place

We need to be checking the value types for the inner setccs not
the outer setcc. We need to ensure those setccs produce a 0/1
value or that the xor is on the i1 type. I think at the time
this code was originally written, getBooleanContents didn't
take any arguments so this was probably correct. But now we can
have a different boolean contents for integer and floating point.

Not sure why the other combines below the xor were also checking
the boolean contents. None of them involve any setccs other than
the outer one and they only produce a new setcc.

Differential Revision: https://reviews.llvm.org/D69480

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 14d08b8b1f29..2ded5674bbb6 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3423,10 +3423,7 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
           return DAG.getSetCC(dl, VT, Val, N1,
                               Cond == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ);
         }
-      } else if (N1C->isOne() &&
-                 (VT == MVT::i1 ||
-                  getBooleanContents(N0.getValueType()) ==
-                      ZeroOrOneBooleanContent)) {
+      } else if (N1C->isOne()) {
         SDValue Op0 = N0;
         if (Op0.getOpcode() == ISD::TRUNCATE)
           Op0 = Op0.getOperand(0);
@@ -3434,10 +3431,18 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
         if ((Op0.getOpcode() == ISD::XOR) &&
             Op0.getOperand(0).getOpcode() == ISD::SETCC &&
             Op0.getOperand(1).getOpcode() == ISD::SETCC) {
-          // (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
-          Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
-          return DAG.getSetCC(dl, VT, Op0.getOperand(0), Op0.getOperand(1),
-                              Cond);
+          SDValue XorLHS = Op0.getOperand(0);
+          SDValue XorRHS = Op0.getOperand(1);
+          // Ensure that the input setccs return an i1 type or 0/1 value.
+          if (Op0.getValueType() == MVT::i1 ||
+              (getBooleanContents(XorLHS.getOperand(0).getValueType()) ==
+                      ZeroOrOneBooleanContent &&
+               getBooleanContents(XorRHS.getOperand(0).getValueType()) ==
+                        ZeroOrOneBooleanContent)) {
+            // (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
+            Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
+            return DAG.getSetCC(dl, VT, XorLHS, XorRHS, Cond);
+          }
         }
         if (Op0.getOpcode() == ISD::AND &&
             isa<ConstantSDNode>(Op0.getOperand(1)) &&