https://gcc.gnu.org/g:612194c064c2ca279191712bcc01f8fcef65ade9
commit r16-3050-g612194c064c2ca279191712bcc01f8fcef65ade9
Author: Sam James <s...@gentoo.org>
Date: Sat Aug 2 13:57:03 2025 +0100
gcc: drop placement new workaround for old bootstrap compilers
Since r15-4719-ga9ec1bc06bd3cc, we require GCC 5.4, so a workaround for
< GCC 4.3 is long-obsolete. Before that, we required GCC 4.8.3 too.
i.e. it shouldn't be possible to build GCC with such a compiler for
quite some time.
gcc/ChangeLog:
PR libstdc++/29286
* Makefile.in (ALIASING_FLAGS): Drop.
* configure: Regenerate.
* configure.ac: Drop -fno-strict-aliasing workaround for < GCC 4.3.
gcc/d/ChangeLog:
* Make-lang.in (ALL_DFLAGS): Don't use ALIASING_FLAGS.
Diff:
---
gcc/Makefile.in | 2 --
gcc/configure | 44 ++------------------------------------------
gcc/configure.ac | 29 -----------------------------
gcc/d/Make-lang.in | 2 +-
4 files changed, 3 insertions(+), 74 deletions(-)
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 340651793473..cc79595dd22a 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -187,8 +187,6 @@ C_STRICT_WARN = @c_strict_warn@
NOEXCEPTION_FLAGS = @noexception_flags@
-ALIASING_FLAGS = @aliasing_flags@
-
# This is set by --disable-maintainer-mode (default) to "#"
# FIXME: 'MAINT' will always be set to an empty string, no matter if
# --disable-maintainer-mode is used or not. This is because the
diff --git a/gcc/configure b/gcc/configure
index bacdd29da69a..cab9c750f03d 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -872,7 +872,6 @@ c_strict_warn
strict_warn
c_loose_warn
loose_warn
-aliasing_flags
CPP
EGREP
GREP
@@ -7126,45 +7125,6 @@ $as_echo "#define HAVE_SWAP_IN_UTILITY 1" >>confdefs.h
fi
-# Check whether compiler is affected by placement new aliasing bug (PR 29286).
-# If the host compiler is affected by the bug, and we build with optimization
-# enabled (which happens e.g. when cross-compiling), the pool allocator may
-# get miscompiled. Use -fno-strict-aliasing to work around this problem.
-# Since there is no reliable feature check for the presence of this bug,
-# we simply use a GCC version number check. (This should never trigger for
-# stages 2 or 3 of a native bootstrap.)
-aliasing_flags=
-if test "$GCC" = yes; then
- saved_CXXFLAGS="$CXXFLAGS"
-
- # The following test compilation will succeed if and only if $CXX accepts
- # -fno-strict-aliasing *and* is older than GCC 4.3.
- CXXFLAGS="$CXXFLAGS -fno-strict-aliasing"
- { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CXX is affected
by placement new aliasing bug" >&5
-$as_echo_n "checking whether $CXX is affected by placement new aliasing bug...
" >&6; }
- cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h. */
-
-#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
-#error compiler not affected by placement new aliasing bug
-#endif
-
-_ACEOF
-if ac_fn_cxx_try_compile "$LINENO"; then :
- { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }; aliasing_flags='-fno-strict-aliasing'
-else
- { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
- CXXFLAGS="$saved_CXXFLAGS"
-fi
-
-
-
-
# ---------------------
# Warnings and checking
# ---------------------
@@ -21522,7 +21482,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 21525 "configure"
+#line 21485 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -21628,7 +21588,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 21631 "configure"
+#line 21591 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
diff --git a/gcc/configure.ac b/gcc/configure.ac
index 2c43b38178c7..ac1f0e944516 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -563,35 +563,6 @@ if test $ac_cv_std_swap_in_utility = yes; then
[Define if <utility> defines std::swap.])
fi
-# Check whether compiler is affected by placement new aliasing bug (PR 29286).
-# If the host compiler is affected by the bug, and we build with optimization
-# enabled (which happens e.g. when cross-compiling), the pool allocator may
-# get miscompiled. Use -fno-strict-aliasing to work around this problem.
-# Since there is no reliable feature check for the presence of this bug,
-# we simply use a GCC version number check. (This should never trigger for
-# stages 2 or 3 of a native bootstrap.)
-aliasing_flags=
-if test "$GCC" = yes; then
- saved_CXXFLAGS="$CXXFLAGS"
-
- # The following test compilation will succeed if and only if $CXX accepts
- # -fno-strict-aliasing *and* is older than GCC 4.3.
- CXXFLAGS="$CXXFLAGS -fno-strict-aliasing"
- AC_MSG_CHECKING([whether $CXX is affected by placement new aliasing bug])
- AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-#if (__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)
-#error compiler not affected by placement new aliasing bug
-#endif
-])],
- [AC_MSG_RESULT([yes]); aliasing_flags='-fno-strict-aliasing'],
- [AC_MSG_RESULT([no])])
-
- CXXFLAGS="$saved_CXXFLAGS"
-fi
-AC_SUBST(aliasing_flags)
-
-
-
# ---------------------
# Warnings and checking
# ---------------------
diff --git a/gcc/d/Make-lang.in b/gcc/d/Make-lang.in
index 2d444c999530..0ddd5242812e 100644
--- a/gcc/d/Make-lang.in
+++ b/gcc/d/Make-lang.in
@@ -61,7 +61,7 @@ WARN_DFLAGS = -Wall -Wdeprecated
NOEXCEPTION_DFLAGS = $(filter-out -fno-rtti, $(NOEXCEPTION_FLAGS))
ALL_DFLAGS = $(DFLAGS-$@) $(GDCFLAGS) -fversion=IN_GCC $(CHECKING_DFLAGS) \
- $(PICFLAG) $(ALIASING_FLAGS) $(NOEXCEPTION_DFLAGS) $(COVERAGE_FLAGS) \
+ $(PICFLAG) $(NOEXCEPTION_DFLAGS) $(COVERAGE_FLAGS) \
$(WARN_DFLAGS)
DCOMPILE.base = $(GDC) -c $(ALL_DFLAGS) -o $@
