diff options
| -rw-r--r-- | tests/benchmarks/corelib/tools/qstring/main.cpp | 84 |
1 files changed, 83 insertions, 1 deletions
diff --git a/tests/benchmarks/corelib/tools/qstring/main.cpp b/tests/benchmarks/corelib/tools/qstring/main.cpp index 6f9c333..4c4d921 100644 --- a/tests/benchmarks/corelib/tools/qstring/main.cpp +++ b/tests/benchmarks/corelib/tools/qstring/main.cpp @@ -1114,6 +1114,86 @@ static int ucstrncmp_ssse3_aligning(const ushort *a, const ushort *b, int len) } } +static inline __attribute__((optimize("no-unroll-loops"))) +int ucstrncmp_ssse3_aligning2_aligned(const ushort *a, const ushort *b, int len) +{ + // len >= 8 + // align(b) == align(a) + + // round down the alignment so align(b) == align(a) == 0 + // calculate how many garbage bytes we'll read on the first load + // corresponds to how many bits we must ignore from movemask's result + int garbage = (quintptr(b) & 0xf); + a -= garbage / 2; + b -= garbage / 2; + + __m128i m1 = _mm_load_si128((const __m128i *)a); + __m128i m2 = _mm_load_si128((const __m128i *)b); + __m128i cmp = _mm_cmpeq_epi16(m1, m2); + int mask = short(_mm_movemask_epi8(cmp)); // force sign extension + mask >>= garbage; + if (~mask) { + // which ushort isn't equal? + int counter = (garbage + bsf_nonzero(~mask))/2; + return a[counter] - b[counter]; + } + + // the first 16-garbage bytes (8-garbage/2 ushorts) were equal + len -= 8 - garbage/2; + return ucstrncmp_sse2_aligned(a + 8, b + 8, len); +} + +template<int N> static inline __attribute__((optimize("no-unroll-loops"))) +int ucstrncmp_ssse3_aligning2_alignr(const ushort *a, const ushort *b, int len) +{ + return ucstrncmp_intwise(a, b, len); +} + +static int ucstrncmp_ssse3_aligning2(const ushort *a, const ushort *b, int len) +{ + // Different strategy from above: instead of doing two unaligned loads + // when trying to align, we'll only do aligned loads and round down the + // addresses of a and b. This means the first load will contain garbage + // in the beginning of the string, which we'll shift out of the way + // (after _mm_movemask_epi8) + + if (len < 16) + return ucstrncmp_intwise(a, b, len); + + // both a and b are misaligned + // we'll call the alignr function with the alignment *difference* between the two + int val = (quintptr(b) & 0xf) - (quintptr(a) & 0xf); + int sign = 1; + if (val < 0) { + val = -val; + qSwap(a, b); + sign = -1; + } + + // from this point on, b has the shortest alignment + // and align(a) = align(b) + val + + if (val == 8) + return ucstrncmp_ssse3_aligning2_alignr<8>(a, b, len) * sign; + else if (val == 0) + return ucstrncmp_ssse3_aligning2_aligned(a, b, len) * sign; + if (val < 8) { + if (val < 4) + return ucstrncmp_ssse3_aligning2_alignr<2>(a, b, len) * sign; + else if (val == 4) + return ucstrncmp_ssse3_aligning2_alignr<4>(a, b, len) * sign; + else + return ucstrncmp_ssse3_aligning2_alignr<6>(a, b, len) * sign; + } else { + if (val < 12) + return ucstrncmp_ssse3_aligning2_alignr<10>(a, b, len) * sign; + else if (val == 12) + return ucstrncmp_ssse3_aligning2_alignr<12>(a, b, len) * sign; + else + return ucstrncmp_ssse3_aligning2_alignr<14>(a, b, len) * sign; + } +} + #endif typedef int (* UcstrncmpFunction)(const ushort *, const ushort *, int); @@ -1129,6 +1209,7 @@ void tst_QString::ucstrncmp_data() const QTest::newRow("sse2_aligning") << &ucstrncmp_sse2_aligning; QTest::newRow("ssse3") << &ucstrncmp_ssse3; QTest::newRow("ssse3_aligning") << &ucstrncmp_ssse3_aligning; + QTest::newRow("ssse3_aligning2") << &ucstrncmp_ssse3_aligning2; } void tst_QString::ucstrncmp() const @@ -1141,7 +1222,8 @@ void tst_QString::ucstrncmp() const &ucstrncmp_sse2, &ucstrncmp_sse2_aligning, &ucstrncmp_ssse3, - &ucstrncmp_ssse3_aligning + &ucstrncmp_ssse3_aligning, + &ucstrncmp_ssse3_aligning2 }; static const int functionCount = sizeof func / sizeof func[0]; |