diff options
| author | Thiago Macieira <thiago.macieira@intel.com> | 2022-10-27 15:55:42 -0700 |
|---|---|---|
| committer | Thiago Macieira <thiago.macieira@intel.com> | 2022-11-16 16:15:31 -0800 |
| commit | d50d34e5de7f5cf5e34243210e3df519974d7794 (patch) | |
| tree | ff86a644a6dc271da7817767e1f7668d7b82ed25 /src/corelib/text/qlocale.cpp | |
| parent | 649dccf57b18626f6a0790d46e5e619e4e603078 (diff) | |
QLocale: make qstrnto(u)ll not have output arguments
That is, return everything in the return argument. On the SysV ABI, that
means everything gets returned in registers, in both 32- and 64-bit
platforms (unlike QtPrivate::ParsedNumber). There's a minor but
perceptible performance improvement in parsing strings and byte arrays.
Before:
Parsed string "42" "1234" "-1548860221"
Clock (ns) 16.673 18.878 25.517
CPU cycles 46.548 52.704 71.243
Instructions 201 233 331
After:
Parsed string "42" "1234" "-1548860221"
Clock (ns) 15.577 17.998 24.198
CPU cycles 43.491 49.942 67.552
Instructions 179 211 308
On my Core i7-1165G7 @ 2.80 GHz, the 22-23 instruction gain per
iteration results in half the expected clock gain in runtime (22 /
2.8 GHz = 7.8 ns) because of a slightly lower instruction per cycle
rate. That's acceptable because we need less speculative execution.
Pick-to: 6.4
Task-number: QTBUG-107788
Change-Id: I07ec23f3cb174fb197c3fffd17220fd64d473cc0
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Diffstat (limited to 'src/corelib/text/qlocale.cpp')
| -rw-r--r-- | src/corelib/text/qlocale.cpp | 14 |
1 files changed, 4 insertions, 10 deletions
diff --git a/src/corelib/text/qlocale.cpp b/src/corelib/text/qlocale.cpp index a6ba1931cb..16c80dd667 100644 --- a/src/corelib/text/qlocale.cpp +++ b/src/corelib/text/qlocale.cpp @@ -4147,11 +4147,8 @@ qulonglong QLocaleData::stringToUnsLongLong(QStringView str, int base, bool *ok, qlonglong QLocaleData::bytearrayToLongLong(QByteArrayView num, int base, bool *ok) { - bool _ok; - const char *endptr; - const qlonglong l = qstrntoll(num.data(), num.size(), &endptr, base, &_ok); - - if (!_ok || endptr == num.data()) { + auto [l, endptr] = qstrntoll(num.data(), num.size(), base); + if (!endptr) { if (ok != nullptr) *ok = false; return 0; @@ -4177,11 +4174,8 @@ qlonglong QLocaleData::bytearrayToLongLong(QByteArrayView num, int base, bool *o qulonglong QLocaleData::bytearrayToUnsLongLong(QByteArrayView num, int base, bool *ok) { - bool _ok; - const char *endptr; - const qulonglong l = qstrntoull(num.data(), num.size(), &endptr, base, &_ok); - - if (!_ok || endptr == num.data()) { + auto [l, endptr] = qstrntoull(num.data(), num.size(), base); + if (!endptr) { if (ok != nullptr) *ok = false; return 0; |