[llvm] b83aa8b - [DAG] computeOverflowForUnsignedAdd - use getMaxValue().ult(2) to detect 0/1 values. NFCI.

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2023-05-06T19:46:34+01:00
New Revision: b83aa8bc75789c0df988dedb9474aaee84ef4bb4

URL: https://github.com/llvm/llvm-project/commit/b83aa8bc75789c0df988dedb9474aaee84ef4bb4
DIFF: https://github.com/llvm/llvm-project/commit/b83aa8bc75789c0df988dedb9474aaee84ef4bb4.diff

LOG: [DAG] computeOverflowForUnsignedAdd - use getMaxValue().ult(2) to detect 0/1 values. NFCI.

Added: 
    

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

Removed: 
    


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diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index a78b7971d327..942d2641ba7d 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3976,15 +3976,11 @@ SelectionDAG::computeOverflowForUnsignedAdd(SDValue N0, SDValue N1) const {
 
   // mulhi + 1 never overflow
   if (N0.getOpcode() == ISD::UMUL_LOHI && N0.getResNo() == 1 &&
-      (N1Known.getMaxValue() & 0x01) == N1Known.getMaxValue())
+      N1Known.getMaxValue().ult(2))
+    return OFK_Never;
+  if (N1.getOpcode() == ISD::UMUL_LOHI && N1.getResNo() == 1 &&
+      computeKnownBits(N0).getMaxValue().ult(2))
     return OFK_Never;
-
-  if (N1.getOpcode() == ISD::UMUL_LOHI && N1.getResNo() == 1) {
-    KnownBits N0Known = computeKnownBits(N0);
-
-    if ((N0Known.getMaxValue() & 0x01) == N0Known.getMaxValue())
-      return OFK_Never;
-  }
 
   // TODO: Add ConstantRange::unsignedAddMayOverflow handling.
   return OFK_Sometime;