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qYieldCpu: ensure we don't use asm statement with MSVC on ARM

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Amends a7f227f56cfe562280e89d3c73040f7e8384129e.

It doesn't support that anywhere except i386, and even there it has a
different syntax than what we're using here. This code assumed ARM was
only ued with GCC-like compilers.

 qglobal.c.obj : error LNK2019: unresolved external symbol asm referenced in function tst_qYieldCpu
 tests\auto\corelib\global\qglobal\tst_qglobal.exe : fatal error LNK1120: 1 unresolved externals

Note: if we're getting here, it means the _YIELD_PROCESSOR() generic
macro was not used, which means there is no ARM YIELD being emitted for
MSVC on ARM for C code (for C++, the macro appears to be working). This
is likely to be a performance issue, which will need to be fixed by
someone who has an interest in improving performance on those
conditions.

Fixes: QTBUG-119881
Change-Id: Ica7a43f6147b49c187ccfffd179f04e1ab643302
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
(cherry picked from commit 91478930711c99c876f0df9475c056445eea96b6)
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Thiago Macieira 2023-12-08 17:15:51 -08:00 committed by Qt Cherry-pick Bot
parent 35ffe8749e
commit 98af9bd9d3
1 changed files with 1 additions and 1 deletions
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2
src/corelib/thread/qyieldcpu.h
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@ -48,7 +48,7 @@ void qYieldCpu(void)
#elif __has_builtin(__builtin_arm_yield)
__builtin_arm_yield();
#elif defined(Q_PROCESSOR_ARM) && Q_PROCESSOR_ARM >= 7
#elif defined(Q_PROCESSOR_ARM) && Q_PROCESSOR_ARM >= 7 && defined(Q_CC_GNU)
asm("yield"); // this works everywhere
#elif __has_builtin(__builtin_riscv_pause)