[llvm] 47ff304 - [RISCV] Use findFirstSet instead of countTrailingZeros. NFC

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2022-12-04T18:00:36-08:00
New Revision: 47ff3042e79b37bbfc19617836cfba1dbbdfec38

URL: https://github.com/llvm/llvm-project/commit/47ff3042e79b37bbfc19617836cfba1dbbdfec38
DIFF: https://github.com/llvm/llvm-project/commit/47ff3042e79b37bbfc19617836cfba1dbbdfec38.diff

LOG: [RISCV] Use findFirstSet instead of countTrailingZeros. NFC

findFirstSet is a wrapper around countTrailingZeros so they are
equivalent here, but I think findFirstSet more cleary describes
the algorithm here.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
index e57c4875c2bf..73cfef8dad37 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMatInt.cpp
@@ -296,9 +296,9 @@ InstSeq generateInstSeq(int64_t Val, const FeatureBitset &ActiveFeatures) {
     // Search for each bit and build corresponding BCLRI/BSETI.
     if (Opc > 0) {
       while (Hi != 0) {
-        unsigned Bit = countTrailingZeros(Hi);
+        unsigned Bit = findFirstSet(Hi, ZB_Undefined);
         TmpSeq.emplace_back(Opc, Bit + 32);
-        Hi &= ~(1 << Bit);
+        Hi &= (Hi - 1); // Clear lowest set bit.
       }
       if (TmpSeq.size() < Res.size())
         Res = TmpSeq;