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Add optimize-for-size case to ucstrncmp 

The SSE code had a case where tail-loop unrolling was disabled when
optimizing for size. What would be even shorter, is to just do a
straight-forward loop over the arrays and compare them. For anything
else, we can just go for speed.

Change-Id: Ifb31650e10e41409972a38014067dbd2927674c9
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
bb10
Erik Verbruggen 2016-10-07 10:59:11 +02:00
parent a897343601
commit 936e132122
1 changed files with 12 additions and 1 deletions
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13
src/corelib/tools/qstring.cpp
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@ -446,6 +446,16 @@ extern "C" int qt_ucstrncmp_mips_dsp_asm(const ushort *a,
// Unicode case-sensitive compare two same-sized strings
static int ucstrncmp(const QChar *a, const QChar *b, int l)
{
#ifdef __OPTIMIZE_SIZE__
const QChar *end = a + l;
while (a < end) {
if (int diff = (int)a->unicode() - (int)b->unicode())
return diff;
++a;
++b;
}
return 0;
#else
#if defined(__mips_dsp)
if (l >= 8) {
return qt_ucstrncmp_mips_dsp_asm(reinterpret_cast<const ushort*>(a),
@ -473,7 +483,7 @@ static int ucstrncmp(const QChar *a, const QChar *b, int l)
- reinterpret_cast<const QChar *>(ptr + distance + idx)->unicode();
}
}
# if defined(Q_COMPILER_LAMBDA) && !defined(__OPTIMIZE_SIZE__)
# if defined(Q_COMPILER_LAMBDA)
const auto &lambda = [=](int i) -> int {
return reinterpret_cast<const QChar *>(ptr)[i].unicode()
- reinterpret_cast<const QChar *>(ptr + distance)[i].unicode();
@ -529,6 +539,7 @@ static int ucstrncmp(const QChar *a, const QChar *b, int l)
}
}
return 0;
#endif
}
static int ucstrncmp(const QChar *a, const uchar *c, int l)