diff options
Diffstat (limited to 'src/corelib/tools')
| -rw-r--r-- | src/corelib/tools/qstring.cpp | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp index 7d409708bb..79365b11b1 100644 --- a/src/corelib/tools/qstring.cpp +++ b/src/corelib/tools/qstring.cpp @@ -559,11 +559,13 @@ static int ucstrncmp(const QChar *a, const uchar *c, int l) } } - // we'll read uc[offset..offset+7] (16 bytes) and c[offset-8..offset+7] (16 bytes) +# ifdef Q_PROCESSOR_X86_64 + enum { MaxTailLength = 7 }; + // we'll read uc[offset..offset+7] (16 bytes) and c[offset..offset+7] (8 bytes) if (uc + offset + 7 < e) { - // same, but we'll throw away half the data - __m128i chunk = _mm_loadu_si128((__m128i*)(c + offset - 8)); - __m128i secondHalf = _mm_unpackhi_epi8(chunk, nullmask); + // same, but we're using an 8-byte load + __m128i chunk = _mm_cvtsi64_si128(*(long long *)(c + offset)); + __m128i secondHalf = _mm_unpacklo_epi8(chunk, nullmask); __m128i ucdata = _mm_loadu_si128((__m128i*)(uc + offset)); __m128i result = _mm_cmpeq_epi16(secondHalf, ucdata); @@ -577,6 +579,10 @@ static int ucstrncmp(const QChar *a, const uchar *c, int l) // still matched offset += 8; } +# else + // 32-bit, we can't do MOVQ to load 8 bytes + enum { MaxTailLength = 15 }; +# endif // reset uc and c uc += offset; @@ -584,7 +590,7 @@ static int ucstrncmp(const QChar *a, const uchar *c, int l) # ifdef Q_COMPILER_LAMBDA const auto &lambda = [=](int i) { return uc[i] - ushort(c[i]); }; - return UnrollTailLoop<7>::exec(e - uc, 0, lambda, lambda); + return UnrollTailLoop<MaxTailLength>::exec(e - uc, 0, lambda, lambda); # endif #endif |