[llvm] 7cdbf1e - Make use of APInt::countLeadingOnes. NFC.

[Jay Foad via llvm-commits]

Author: Jay Foad
Date: 2020-03-23T09:08:20Z
New Revision: 7cdbf1ed4b94259a3aad2a7575e928fa61b0e57e

URL: https://github.com/llvm/llvm-project/commit/7cdbf1ed4b94259a3aad2a7575e928fa61b0e57e
DIFF: https://github.com/llvm/llvm-project/commit/7cdbf1ed4b94259a3aad2a7575e928fa61b0e57e.diff

LOG: Make use of APInt::countLeadingOnes. NFC.

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 5b673486af15..58311069c09a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4048,13 +4048,10 @@ unsigned SelectionDAG::ComputeNumSignBits(SDValue Op, const APInt &DemandedElts,
     return FirstAnswer;
   }
 
-  // Okay, we know that the sign bit in Mask is set.  Use CLZ to determine
+  // Okay, we know that the sign bit in Mask is set.  Use CLO to determine
   // the number of identical bits in the top of the input value.
-  Mask = ~Mask;
   Mask <<= Mask.getBitWidth()-VTBits;
-  // Return # leading zeros.  We use 'min' here in case Val was zero before
-  // shifting.  We don't want to return '64' as for an i32 "0".
-  return std::max(FirstAnswer, std::min(VTBits, Mask.countLeadingZeros()));
+  return std::max(FirstAnswer, Mask.countLeadingOnes());
 }
 
 bool SelectionDAG::isBaseWithConstantOffset(SDValue Op) const {