MaskRay created this revision.
MaskRay added a reviewer: bkramer.
Herald added a subscriber: cfe-commits.
SSE2 vectorization was added in 2012, but it is 2018 now and I can't
observe any performance boost with the existing _mm_movemask_epi8 or the
following SSE4.2 (compiling with -msse4.2):
__m128i C = _mm_setr_epi8('\r','\n',0,0,0,0,0,0,0,0,0,0,0,0,0,0);
_mm_cmpestri(C, 2, Chunk, 16, _SIDD_UBYTE_OPS | _SIDD_CMP_EQUAL_ANY |
_SIDD_POSITIVE_POLARITY | _SIDD_LEAST_SIGNIFICANT)
Delete the vectorization to simplify the code.
Also don't check the line ending sequence \n\r
Repository:
rC Clang
https://reviews.llvm.org/D55484
Files:
lib/Basic/SourceManager.cpp
Index: lib/Basic/SourceManager.cpp
===================================================================
--- lib/Basic/SourceManager.cpp
+++ lib/Basic/SourceManager.cpp
@@ -1216,65 +1216,22 @@
const unsigned char *Buf = (const unsigned char *)Buffer->getBufferStart();
const unsigned char *End = (const unsigned char *)Buffer->getBufferEnd();
- unsigned Offs = 0;
+ unsigned I = 0;
while (true) {
// Skip over the contents of the line.
- const unsigned char *NextBuf = (const unsigned char *)Buf;
-
-#ifdef __SSE2__
- // Try to skip to the next newline using SSE instructions. This is very
- // performance sensitive for programs with lots of diagnostics and in -E
- // mode.
- __m128i CRs = _mm_set1_epi8('\r');
- __m128i LFs = _mm_set1_epi8('\n');
-
- // First fix up the alignment to 16 bytes.
- while (((uintptr_t)NextBuf & 0xF) != 0) {
- if (*NextBuf == '\n' || *NextBuf == '\r' || *NextBuf == '\0')
- goto FoundSpecialChar;
- ++NextBuf;
- }
-
- // Scan 16 byte chunks for '\r' and '\n'. Ignore '\0'.
- while (NextBuf+16 <= End) {
- const __m128i Chunk = *(const __m128i*)NextBuf;
- __m128i Cmp = _mm_or_si128(_mm_cmpeq_epi8(Chunk, CRs),
- _mm_cmpeq_epi8(Chunk, LFs));
- unsigned Mask = _mm_movemask_epi8(Cmp);
-
- // If we found a newline, adjust the pointer and jump to the handling
code.
- if (Mask != 0) {
- NextBuf += llvm::countTrailingZeros(Mask);
- goto FoundSpecialChar;
- }
- NextBuf += 16;
- }
-#endif
-
- while (*NextBuf != '\n' && *NextBuf != '\r' && *NextBuf != '\0')
- ++NextBuf;
-
-#ifdef __SSE2__
-FoundSpecialChar:
-#endif
- Offs += NextBuf-Buf;
- Buf = NextBuf;
-
- if (Buf[0] == '\n' || Buf[0] == '\r') {
- // If this is \n\r or \r\n, skip both characters.
- if ((Buf[1] == '\n' || Buf[1] == '\r') && Buf[0] != Buf[1]) {
- ++Offs;
- ++Buf;
- }
- ++Offs;
- ++Buf;
- LineOffsets.push_back(Offs);
+ while (Buf[I] != '\n' && Buf[I] != '\r' && Buf[I] != '\0')
+ ++I;
+
+ if (Buf[I] == '\n' || Buf[I] == '\r') {
+ // If this is \r\n, skip both characters.
+ if (Buf[I] == '\r' && Buf[I+1] == '\n')
+ ++I;
+ ++I;
+ LineOffsets.push_back(I);
} else {
- // Otherwise, this is a null. If end of file, exit.
- if (Buf == End) break;
- // Otherwise, skip the null.
- ++Offs;
- ++Buf;
+ // Otherwise, this is a NUL. If end of file, exit.
+ if (Buf+I == End) break;
+ ++I;
}
}
Index: lib/Basic/SourceManager.cpp
===================================================================
--- lib/Basic/SourceManager.cpp
+++ lib/Basic/SourceManager.cpp
@@ -1216,65 +1216,22 @@
const unsigned char *Buf = (const unsigned char *)Buffer->getBufferStart();
const unsigned char *End = (const unsigned char *)Buffer->getBufferEnd();
- unsigned Offs = 0;
+ unsigned I = 0;
while (true) {
// Skip over the contents of the line.
- const unsigned char *NextBuf = (const unsigned char *)Buf;
-
-#ifdef __SSE2__
- // Try to skip to the next newline using SSE instructions. This is very
- // performance sensitive for programs with lots of diagnostics and in -E
- // mode.
- __m128i CRs = _mm_set1_epi8('\r');
- __m128i LFs = _mm_set1_epi8('\n');
-
- // First fix up the alignment to 16 bytes.
- while (((uintptr_t)NextBuf & 0xF) != 0) {
- if (*NextBuf == '\n' || *NextBuf == '\r' || *NextBuf == '\0')
- goto FoundSpecialChar;
- ++NextBuf;
- }
-
- // Scan 16 byte chunks for '\r' and '\n'. Ignore '\0'.
- while (NextBuf+16 <= End) {
- const __m128i Chunk = *(const __m128i*)NextBuf;
- __m128i Cmp = _mm_or_si128(_mm_cmpeq_epi8(Chunk, CRs),
- _mm_cmpeq_epi8(Chunk, LFs));
- unsigned Mask = _mm_movemask_epi8(Cmp);
-
- // If we found a newline, adjust the pointer and jump to the handling code.
- if (Mask != 0) {
- NextBuf += llvm::countTrailingZeros(Mask);
- goto FoundSpecialChar;
- }
- NextBuf += 16;
- }
-#endif
-
- while (*NextBuf != '\n' && *NextBuf != '\r' && *NextBuf != '\0')
- ++NextBuf;
-
-#ifdef __SSE2__
-FoundSpecialChar:
-#endif
- Offs += NextBuf-Buf;
- Buf = NextBuf;
-
- if (Buf[0] == '\n' || Buf[0] == '\r') {
- // If this is \n\r or \r\n, skip both characters.
- if ((Buf[1] == '\n' || Buf[1] == '\r') && Buf[0] != Buf[1]) {
- ++Offs;
- ++Buf;
- }
- ++Offs;
- ++Buf;
- LineOffsets.push_back(Offs);
+ while (Buf[I] != '\n' && Buf[I] != '\r' && Buf[I] != '\0')
+ ++I;
+
+ if (Buf[I] == '\n' || Buf[I] == '\r') {
+ // If this is \r\n, skip both characters.
+ if (Buf[I] == '\r' && Buf[I+1] == '\n')
+ ++I;
+ ++I;
+ LineOffsets.push_back(I);
} else {
- // Otherwise, this is a null. If end of file, exit.
- if (Buf == End) break;
- // Otherwise, skip the null.
- ++Offs;
- ++Buf;
+ // Otherwise, this is a NUL. If end of file, exit.
+ if (Buf+I == End) break;
+ ++I;
}
}
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