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Implement an sse2 version of the block comment scanner. 

llvm-svn: 39060
This commit is contained in:
Chris Lattner 2006-10-27 04:42:31 +00:00
parent 6cc3e36cd7
commit aded4a977d
1 changed files with 17 additions and 1 deletions
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18
clang/Lex/Lexer.cpp
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@ -770,6 +770,10 @@ static bool isEndOfBlockCommentWithEscapedNewLine(const char *CurPtr,
return true;
}
#ifdef __SSE2__
#include <emmintrin.h>
#endif
/// SkipBlockComment - We have just read the /* characters from input. Read
/// until we find the */ characters that terminate the comment. Note that we
/// don't bother decoding trigraphs or escaped newlines in block comments,
@ -799,7 +803,15 @@ bool Lexer::SkipBlockComment(LexerToken &Result, const char *CurPtr) {
C = *CurPtr++;
if (C == '/') goto FoundSlash;
#ifdef __SSE2__
__m128i Slashes = _mm_set_epi8('/', '/', '/', '/', '/', '/', '/', '/',
'/', '/', '/', '/', '/', '/', '/', '/');
while (CurPtr+16 <= BufferEnd &&
_mm_movemask_epi8(_mm_cmpeq_epi8(*(__m128i*)CurPtr, Slashes)) == 0)
CurPtr += 16;
#else
// Scan for '/' quickly. Many block comments are very large.
while (CurPtr[0] != '/' &&
CurPtr[1] != '/' &&
CurPtr[2] != '/' &&
@ -807,9 +819,13 @@ bool Lexer::SkipBlockComment(LexerToken &Result, const char *CurPtr) {
CurPtr+4 < BufferEnd) {
CurPtr += 4;
}
#endif
// It has to be one of the bytes scanned, increment to it and read one.
C = *CurPtr++;
}
// Loop to scan the remainder.
while (C != '/' && C != '\0')
C = *CurPtr++;