From: Jakub Jelinek <jakub@redhat.com>
Date: Thu, 22 Apr 2021 13:08:21 +0000 (+0200)
Subject: libstdc++: Add workaround for ia32 floating atomics miscompilations [PR100184]
X-Git-Tag: basepoints/gcc-13~8253
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0f4588141fcbe4e0f1fa12776b47200870f6c621;p=thirdparty%2Fgcc.git

libstdc++: Add workaround for ia32 floating atomics miscompilations [PR100184]

gcc on ia32 miscompiles various atomics involving floating point,
unfortunately I'm afraid it is too late to fix that for 11.1 and
as I'm quite lost on it, it might take a while for 12 too
(disabling all the 8 peephole2s would be easiest, but then we'd
run into optimization regressions).

While 1.cc just FAILs, with dejagnu 1.6.1 wait_notify.cc hangs the
make check even after the timeout fires.  The following patch therefore
xfails the former and skips the latter.

Tested on x86_64-linux where
make check RUNTESTFLAGS='conformance.exp=atomic_float/*.cc'
is still
                === libstdc++ Summary ===

 # of expected passes            8
and on i686-linux, where it is now
                === libstdc++ Summary ===

 # of expected passes            5
 # of expected failures          1
 # of unsupported tests          1

2021-04-22  Jakub Jelinek  <jakub@redhat.com>

	PR target/100182
	* testsuite/29_atomics/atomic_float/1.cc: Add dg-xfail-run-if for
	ia32.
	* testsuite/29_atomics/atomic_float/wait_notify.cc: Add dg-skip-if for
	ia32.
---

diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_float/1.cc b/libstdc++-v3/testsuite/29_atomics/atomic_float/1.cc
index b2008368a95a..797d3b7ecbe8 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_float/1.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_float/1.cc
@@ -18,6 +18,7 @@
 // { dg-add-options ieee }
 // { dg-options "-std=gnu++2a" }
 // { dg-do run { target c++2a } }
+// { dg-xfail-run-if "PR100182" { ia32 } }
 
 #include <atomic>
 #include <testsuite_hooks.h>
diff --git a/libstdc++-v3/testsuite/29_atomics/atomic_float/wait_notify.cc b/libstdc++-v3/testsuite/29_atomics/atomic_float/wait_notify.cc
index 01768da290b7..e0ff34dbf24d 100644
--- a/libstdc++-v3/testsuite/29_atomics/atomic_float/wait_notify.cc
+++ b/libstdc++-v3/testsuite/29_atomics/atomic_float/wait_notify.cc
@@ -2,6 +2,7 @@
 // { dg-do run { target c++2a } }
 // { dg-require-gthreads "" }
 // { dg-additional-options "-pthread" { target pthread } }
+// { dg-skip-if "PR100182" { ia32 } }
 // { dg-add-options libatomic }
 
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