[llvm] c9790f8 - [IR] Use SmallDenseSet (NFC) (#79556)
via llvm-commits
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Fri Jan 26 17:18:46 PST 2024
Author: Kazu Hirata
Date: 2024-01-26T17:18:42-08:00
New Revision: c9790f8f733f6014fdd8bdacb057c9871e624bcc
URL: https://github.com/llvm/llvm-project/commit/c9790f8f733f6014fdd8bdacb057c9871e624bcc
DIFF: https://github.com/llvm/llvm-project/commit/c9790f8f733f6014fdd8bdacb057c9871e624bcc.diff
LOG: [IR] Use SmallDenseSet (NFC) (#79556)
The use of SmallDenseSet saves 0.39% of heap allocations during the
compilation of a large preprocessed file, namely X86ISelLowering.cpp,
for the X86 target. During the experiment, WL.size() was 2 or less
99.9% of the time. The inline size of 4 should accommodate up to 2
entries at the 3/4 occupancy rate.
Added:
Modified:
llvm/lib/IR/Instruction.cpp
Removed:
################################################################################
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
index f9a38e48166c9ab..904ce17fb0e7c97 100644
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -1167,9 +1167,7 @@ void Instruction::copyMetadata(const Instruction &SrcInst,
if (!SrcInst.hasMetadata())
return;
- DenseSet<unsigned> WLS;
- for (unsigned M : WL)
- WLS.insert(M);
+ SmallDenseSet<unsigned, 4> WLS(WL.begin(), WL.end());
// Otherwise, enumerate and copy over metadata from the old instruction to the
// new one.
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