buildroot/package/qt6/qt6base/0001-src-corelib-global-qsimd_p.h-fix-build-on-ARM-v7-due.patch

From d69db2ba3ce47f6eded0a8843c413a67d26e6375 Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Date: Sun, 24 Jul 2022 20:37:51 +0200
Subject: [PATCH] src/corelib/global/qsimd_p.h: fix build on ARM < v7 due to
 yield instruction

On ARM < v7 with gcc, the build fails with:

/tmp/ccRlrCQi.s: Assembler messages:
/tmp/ccRlrCQi.s:3858: Error: selected processor does not support `yield' in ARM mode
/tmp/ccRlrCQi.s:3875: Error: selected processor does not support `yield' in ARM mode
/tmp/ccRlrCQi.s:4606: Error: selected processor does not support `yield' in ARM mode
/tmp/ccRlrCQi.s:4853: Error: selected processor does not support `yield' in ARM mode
/tmp/ccRlrCQi.s:5268: Error: selected processor does not support `yield' in ARM mode

while building src/corelib/thread/qfutureinterface.cpp.

This is due to the fact that the qYieldCpu() macro on ARM, assumes
that if the compiler is gcc, we can do asm volatile("yield"). However,
this instruction is only guaranteed to exist on ARMv7+ cores. It
doesn't exist on ARMv5, and only some (but not all) ARMv6 cores have
it. If it's not available, we just fallback to the default behavior of
qYieldCpu(), which is to do nothing.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Upstream bug: https://bugreports.qt.io/browse/QTBUG-105162
---
 src/corelib/global/qsimd_p.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/corelib/global/qsimd_p.h b/src/corelib/global/qsimd_p.h
index d270d09f2f..b84b257e54 100644
--- a/src/corelib/global/qsimd_p.h
+++ b/src/corelib/global/qsimd_p.h
@@ -428,7 +428,10 @@ static inline void qYieldCpu()
          https://stackoverflow.com/a/70076751/134841
          https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105416
     */
-    asm volatile("yield"); /* this works everywhere */
+#    if defined(Q_PROCESSOR_ARM_V7)
+    /* The yield instruction appeared in ARMv7 */
+    asm volatile("yield");
+#    endif
 #  else
     __yield(); /* this is what should work everywhere */
 #  endif
-- 
2.37.1