* [committed] libstdc++: Add comment to acinclude.m4
@ 2022-02-08 14:25 Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2022-02-08 14:25 UTC (permalink / raw)
To: libstdc++, gcc-patches
Tested x86_64-linux, pushed to trunk.
libstdc++-v3/ChangeLog:
* acinclude.m4 (GLIBCXX_ENABLE_LOCK_POLICY): Add comment about
checking for CAS on correct word size.
---
libstdc++-v3/acinclude.m4 | 2 ++
1 file changed, 2 insertions(+)
diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 7cc52f4db96..f53461c85a5 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -3609,6 +3609,8 @@ AC_DEFUN([GLIBCXX_ENABLE_LOCK_POLICY], [
ac_save_CXXFLAGS="$CXXFLAGS"
dnl Why do we care about 2-byte CAS on targets with 4-byte _Atomic_word?!
+ dnl Why don't we check 8-byte CAS for sparc64, where _Atomic_word is long?!
+ dnl New targets should only check for CAS for the _Atomic_word type.
AC_TRY_COMPILE([
#if ! defined __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2
# error "No 2-byte compare-and-swap"
--
2.34.1
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2022-02-08 14:25 [committed] libstdc++: Add comment to acinclude.m4 Jonathan Wakely
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