https://github.com/serge-sans-paille updated
https://github.com/llvm/llvm-project/pull/71865
>From 65e931aa7bde6fffe3dfeee1a2147c8fcd73f0af Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguel...@mozilla.com>
Date: Mon, 13 Nov 2023 08:59:29 +0100
Subject: [PATCH 1/2] Replace usage of StringRef::find_last_of with a string
literal of size one by the equivalent char literal
---
clang/lib/Driver/ToolChains/ZOS.cpp | 2 +-
llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp | 2 +-
llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp | 2 +-
mlir/lib/Tools/lsp-server-support/SourceMgrUtils.cpp | 2 +-
4 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/clang/lib/Driver/ToolChains/ZOS.cpp
b/clang/lib/Driver/ToolChains/ZOS.cpp
index a7d6f030f3850a5..96dbf602e7c1fc9 100644
--- a/clang/lib/Driver/ToolChains/ZOS.cpp
+++ b/clang/lib/Driver/ToolChains/ZOS.cpp
@@ -143,7 +143,7 @@ void zos::Linker::ConstructJob(Compilation &C, const
JobAction &JA,
StringRef OutputName = Output.getFilename();
// Strip away the last file suffix in presence from output name and add
// a new .x suffix.
- size_t Suffix = OutputName.find_last_of(".");
+ size_t Suffix = OutputName.find_last_of('.');
const char *SideDeckName =
Args.MakeArgString(OutputName.substr(0, Suffix) + ".x");
CmdArgs.push_back("-x");
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp
b/llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp
index d03820f5f9e6c93..7b5dc3795b0227f 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUPrintfRuntimeBinding.cpp
@@ -102,7 +102,7 @@ void
AMDGPUPrintfRuntimeBindingImpl::getConversionSpecifiers(
bool ArgDump = false;
StringRef CurFmt = Fmt.substr(PrevFmtSpecifierIdx,
CurFmtSpecifierIdx - PrevFmtSpecifierIdx);
- size_t pTag = CurFmt.find_last_of("%");
+ size_t pTag = CurFmt.find_last_of('%');
if (pTag != StringRef::npos) {
ArgDump = true;
while (pTag && CurFmt[--pTag] == '%') {
diff --git a/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
b/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
index d6354876b558744..ae9e801f8f50b84 100644
--- a/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVBuiltins.cpp
@@ -163,7 +163,7 @@ lookupBuiltin(StringRef DemangledCall,
// the information after angle brackets and return type removed.
if (BuiltinName.find('<') && BuiltinName.back() == '>') {
BuiltinName = BuiltinName.substr(0, BuiltinName.find('<'));
- BuiltinName = BuiltinName.substr(BuiltinName.find_last_of(" ") + 1);
+ BuiltinName = BuiltinName.substr(BuiltinName.find_last_of(' ') + 1);
}
// Check if the extracted name begins with "__spirv_ImageSampleExplicitLod"
diff --git a/mlir/lib/Tools/lsp-server-support/SourceMgrUtils.cpp
b/mlir/lib/Tools/lsp-server-support/SourceMgrUtils.cpp
index fe668130d4e2dbc..b6f4f3cc1869edb 100644
--- a/mlir/lib/Tools/lsp-server-support/SourceMgrUtils.cpp
+++ b/mlir/lib/Tools/lsp-server-support/SourceMgrUtils.cpp
@@ -83,7 +83,7 @@ lsp::extractSourceDocComment(llvm::SourceMgr &sourceMgr,
SMLoc loc) {
// Pop the last line from the buffer string.
auto popLastLine = [&]() -> std::optional<StringRef> {
- size_t newlineOffset = buffer.find_last_of("\n");
+ size_t newlineOffset = buffer.find_last_of('\n');
if (newlineOffset == StringRef::npos)
return std::nullopt;
StringRef lastLine = buffer.drop_front(newlineOffset).trim();
>From 2e48f5a337bdecc671e174c4b0a2a77174d30b9f Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguel...@mozilla.com>
Date: Thu, 9 Nov 2023 20:41:40 +0100
Subject: [PATCH 2/2] [llvm] Improve implementation of StringRef::find_last_of
for the usual case of 2 chars
Almost all usage of StringRef::find_last_of in Clang/LLVM use a Needle
of 2 elements, which can easily be optimized in SSE2. The IPC of the
improved version is significantly better as shown in
https://godbolt.org/z/h1dsdcMd8
And it does not require an extra structure.
---
llvm/lib/Support/StringRef.cpp | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/llvm/lib/Support/StringRef.cpp b/llvm/lib/Support/StringRef.cpp
index feee47ca693b251..9c87f2fe764989a 100644
--- a/llvm/lib/Support/StringRef.cpp
+++ b/llvm/lib/Support/StringRef.cpp
@@ -15,6 +15,10 @@
#include "llvm/Support/Error.h"
#include <bitset>
+#ifdef __SSE2__
+#include <emmintrin.h>
+#endif
+
using namespace llvm;
// MSVC emits references to this into the translation units which reference it.
@@ -274,6 +278,23 @@ StringRef::size_type
StringRef::find_first_not_of(StringRef Chars,
/// Note: O(size() + Chars.size())
StringRef::size_type StringRef::find_last_of(StringRef Chars,
size_t From) const {
+#ifdef __SSE2__
+ if (Chars.size() == 2) {
+ __m128i Needle0 = _mm_set1_epi8(Chars[0]);
+ __m128i Needle1 = _mm_set1_epi8(Chars[1]);
+ size_type Sz = std::min(From, Length);
+ do {
+ Sz = Sz < 16 ? 0 : Sz - 16;
+ __m128i Buffer = _mm_loadu_si128((const __m128i *)(Data + Sz));
+ unsigned Mask = _mm_movemask_epi8(_mm_or_si128(
+ _mm_cmpeq_epi8(Buffer, Needle0), _mm_cmpeq_epi8(Buffer, Needle1)));
+ if (Mask != 0) {
+ return Sz + sizeof(Mask) * CHAR_BIT - llvm::countl_zero(Mask);
+ }
+ } while (Sz);
+ return npos;
+ }
+#endif
std::bitset<1 << CHAR_BIT> CharBits;
for (char C : Chars)
CharBits.set((unsigned char)C);
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