On Tue, Apr 12, 2022 at 1:53 AM Steve Kargl via Gcc <gcc@gcc.gnu.org> wrote:
>
> If I configure gcc with the following
>
> ../gccx/configure --prefix=$HOME/work/x --enable-languages=c,c++,fortran \
> --enable-bootstrap --disable-nls --enable-checking --disable-multilib \
> --disable-libsanitizer --disable-lto.
>
> then bootstrap gcc, why do I see 1000s of failures with
>
> % cd gcc
> % gmake -j7 check-c
> ...
> FAIL: gcc.dg/torture/pr64365.c -O2 -flto (test for excess errors)
> FAIL: gcc.dg/torture/pr61786.c -O2 -flto (test for excess errors)
> FAIL: gcc.dg/torture/pr63380-2.c -O2 -flto (test for excess errors)
> FAIL: gcc.dg/torture/pr65270-2.c -O2 -flto (test for excess errors)
>
> Should the testsuite recognize that gcc is built without LTO support?
Yes, it does, in testsuite/lib/gcc-dg.exp
if [info exists TORTURE_OPTIONS] {
set DG_TORTURE_OPTIONS $TORTURE_OPTIONS
} else {
# It is theoretically beneficial to group all of the O2/O3 options together,
# as in many cases the compiler will generate identical executables for
# all of them--and the c-torture testsuite will skip testing identical
# executables multiple times.
# Also note that -finline-functions is explicitly included in one of the
# items below, even though -O3 is also specified, because some ports may
# choose to disable inlining functions by default, even when optimizing.
set DG_TORTURE_OPTIONS [list \
{ -O0 } \
{ -O1 } \
{ -O2 } \
{ -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops
-ftracer -finline-functions } \
{ -O3 -g } \
{ -Os } ]
if [check_effective_target_lto] {
# When having plugin test both slim and fat LTO and plugin/nonplugin
# path.
if [check_linker_plugin_available] {
set LTO_TORTURE_OPTIONS [list \
{ -O2 -flto -fno-use-linker-plugin -flto-partition=none } \
{ -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects }
]
} else {
set LTO_TORTURE_OPTIONS [list \
{ -O2 -flto -flto-partition=none } \
{ -O2 -flto }
]
}
so either TORTURE_OPTIONS is set or check_effective_target_lto doesn't work.
The check does simply
return [check_no_compiler_messages lto object {
void foo (void) { }
} "-flto"]
so I wonder what your excess errors are? The check above should also
leave traces
in the testsuite log. It might be that --disable-lto doesn't disable
gcc -c -flto but just
disables lto1 building though.
>
> --
> Steve
