[llvm] 5660dc5 - [TargetLowering] Simplify some code in SimplifySetCC that tries to handle SIGN_EXTEND_INREG operand types that should never happen. NFCI

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2021-01-21T23:56:37-08:00
New Revision: 5660dc5968ec6dacba1917b741d660c582f69e9e

URL: https://github.com/llvm/llvm-project/commit/5660dc5968ec6dacba1917b741d660c582f69e9e
DIFF: https://github.com/llvm/llvm-project/commit/5660dc5968ec6dacba1917b741d660c582f69e9e.diff

LOG: [TargetLowering] Simplify some code in SimplifySetCC that tries to handle SIGN_EXTEND_INREG operand types that should never happen. NFCI

There was code to handle the first operand being different than
the result type. And code to handle first operand having the
same type as the type to extend from. This should never happen
for a correctly formed SIGN_EXTEND_INREG. I've replace the
code with asserts.

I also noticed we created the same APInt twice so I've reused it.

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 e2f42d050740..3d1d257ae54c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -3747,24 +3747,16 @@ SDValue TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
       if (C1.getMinSignedBits() > ExtSrcTyBits)
         return DAG.getConstant(Cond == ISD::SETNE, dl, VT);
 
-      SDValue ZextOp;
-      EVT Op0Ty = N0.getOperand(0).getValueType();
-      if (Op0Ty == ExtSrcTy) {
-        ZextOp = N0.getOperand(0);
-      } else {
-        APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
-        ZextOp = DAG.getNode(ISD::AND, dl, Op0Ty, N0.getOperand(0),
-                             DAG.getConstant(Imm, dl, Op0Ty));
-      }
+      assert(ExtDstTy == N0.getOperand(0).getValueType() &&
+             ExtDstTy != ExtSrcTy && "Unexpected types!");
+      APInt Imm = APInt::getLowBitsSet(ExtDstTyBits, ExtSrcTyBits);
+      SDValue ZextOp = DAG.getNode(ISD::AND, dl, ExtDstTy, N0.getOperand(0),
+                                   DAG.getConstant(Imm, dl, ExtDstTy));
       if (!DCI.isCalledByLegalizer())
         DCI.AddToWorklist(ZextOp.getNode());
       // Otherwise, make this a use of a zext.
       return DAG.getSetCC(dl, VT, ZextOp,
-                          DAG.getConstant(C1 & APInt::getLowBitsSet(
-                                                              ExtDstTyBits,
-                                                              ExtSrcTyBits),
-                                          dl, ExtDstTy),
-                          Cond);
+                          DAG.getConstant(C1 & Imm, dl, ExtDstTy), Cond);
     } else if ((N1C->isNullValue() || N1C->isOne()) &&
                 (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
       // SETCC (SETCC), [0|1], [EQ|NE]  -> SETCC