http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53579
Bug #: 53579
Summary: libstdc++ configure atomicity tests use CXXFLAGS
instead of CXXFLAGS_FOR_TARGET
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: olege...@gcc.gnu.org
When trying to fix PR 29366 by removing config/cpu/sh/atomicity.h I've noticed
that libstdc++'s configure would refuse to pick up
config/cpu/generic/atomicity_builtins.
On the SH target atomicity builtins have to be enabled by either -msoft-atomic
or -mhard-atomic. For sh-linux -msoft-atomic is enabled by default. When
building a cross toolchain (top level make) CFLAGS_FOR_TARGET /
CXXFLAGS_FOR_TARGET can be used to enable the atomicity builtins. However,
libstdc++ configure uses CXXFLAGS when testing for atomicity builtins
availability, so it will default to using config/cpu/generic/atomicity_mutex.
I'm not quite sure where the fix should go, either in the top level
configure/makefile (which fails to set CXXFLAGS to CXXFLAGS_FOR_TARGET for
libstdc++ configure) or libstdc++ itself, because when libstdc++ is actually
compiled CXXFLAGS_FOR_TARGET is passed to xgcc as expected.
