| Message ID | 20210114210431.463242-4-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Build x86 libitm/libgomp/libatomic with -march=i486 or better | expand |
On Thu, Jan 14, 2021 at 01:04:31PM -0800, H.J. Lu via Gcc-patches wrote: > If x86 libatomic isn't compiled with -march=i486 or better, append > -march=i486 XCFLAGS for x86 libatomic build. Set try_ifunc to yes > if -mcx16 isn't used to compile x86-64 libatomic or -march=i686 or > better isn't used to compile x86 libatomic. > > PR target/70454 > * configure.tgt (XCFLAGS): Append -march=i486 to compile x86 > libatomic if needed. > (try_ifunc): Set to yes only if needed. > --- > libatomic/configure.tgt | 73 ++++++++++++++++++++++++++++------------- > 1 file changed, 50 insertions(+), 23 deletions(-) > > diff --git a/libatomic/configure.tgt b/libatomic/configure.tgt > index 2f24817b454..1f3a3ad6c7c 100644 > --- a/libatomic/configure.tgt > +++ b/libatomic/configure.tgt > @@ -81,32 +81,59 @@ case "${target_cpu}" in > ARCH=sparc > ;; > > - i[3456]86) > - case " ${CC} ${CFLAGS} " in > - *" -m64 "*|*" -mx32 "*) > - ;; > - *) > - if test -z "$with_arch"; then > - XCFLAGS="${XCFLAGS} -march=i486 -mtune=${target_cpu}" > - XCFLAGS="${XCFLAGS} -fomit-frame-pointer" > - fi > - esac > - ARCH=x86 > - # ??? Detect when -march=i686 is already enabled. > - try_ifunc=yes > - ;; > - x86_64) > - case " ${CC} ${CFLAGS} " in > - *" -m32 "*) > + i[3456]86 | x86_64) > + # Need i486 or better. > + cat > conftestx.c <<EOF > +#if defined __x86_64__ || defined __i486__ || defined __pentium__ \ > + || defined __pentiumpro__ || defined __pentium4__ \ > + || defined __geode__ || defined __SSE__ > +# error Need i486 or better > +#endif Rather than hoping we got all the defines right, wouldn't it be better to compile with -S a testcase like: int foo (int *p, int x, int y) { return __sync_val_compare_and_swap (p, x, y); } and if there is __sync_val_compare_and_swap_4 in the assembly assume -march=i486 needs to be added? I.e. test for what exactly we need (working atomics). Jakub
diff --git a/libatomic/configure.tgt b/libatomic/configure.tgt index 2f24817b454..1f3a3ad6c7c 100644 --- a/libatomic/configure.tgt +++ b/libatomic/configure.tgt @@ -81,32 +81,59 @@ case "${target_cpu}" in ARCH=sparc ;; - i[3456]86) - case " ${CC} ${CFLAGS} " in - *" -m64 "*|*" -mx32 "*) - ;; - *) - if test -z "$with_arch"; then - XCFLAGS="${XCFLAGS} -march=i486 -mtune=${target_cpu}" - XCFLAGS="${XCFLAGS} -fomit-frame-pointer" - fi - esac - ARCH=x86 - # ??? Detect when -march=i686 is already enabled. - try_ifunc=yes - ;; - x86_64) - case " ${CC} ${CFLAGS} " in - *" -m32 "*) + i[3456]86 | x86_64) + # Need i486 or better. + cat > conftestx.c <<EOF +#if defined __x86_64__ || defined __i486__ || defined __pentium__ \ + || defined __pentiumpro__ || defined __pentium4__ \ + || defined __geode__ || defined __SSE__ +# error Need i486 or better +#endif +EOF + if ${CC} ${CFLAGS} -c -o conftestx.o conftestx.c > /dev/null 2>&1; then + if test "${target_cpu}" = x86_64; then XCFLAGS="${XCFLAGS} -march=i486 -mtune=generic" XCFLAGS="${XCFLAGS} -fomit-frame-pointer" - ;; - *) - ;; - esac + else + XCFLAGS="${XCFLAGS} -march=i486 -mtune=${target_cpu}" + XCFLAGS="${XCFLAGS} -fomit-frame-pointer" + fi + fi + # Detect if -march=i686/-mcx16 is already enabled. + cat > conftestx.c <<EOF +#if defined __x86_64__ +__int128_t v = 0; +__int128_t expected = 0; +__int128_t max = ~0; +__int128_t desired = ~0; +__int128_t zero = 0; + +int +foo (void) +{ + return !__atomic_compare_exchange_n (&v, &expected, max, 0, + __ATOMIC_RELAXED, + __ATOMIC_RELAXED); +} +#else +# if defined __pentiumpro__ || defined __pentium4__ || defined __SSE__ +asm ("# has i686"); +# endif +#endif +EOF + if ${CC} ${CFLAGS} -S -o conftestx.s conftestx.c > /dev/null 2>&1; then + if ${GREP} cmpxchg16b conftestx.s >/dev/null; then + # This is the 64-bit library. + try_ifunc=no + elif ${GREP} i686 conftestx.s >/dev/null; then + # This is the 32-bit library. + try_ifunc=no + else + try_ifunc=yes + fi + fi + rm -f conftestx.c conftestx.o conftestx.s ARCH=x86 - # ??? Detect when -mcx16 is already enabled. - try_ifunc=yes ;; *) ARCH="${target_cpu}" ;;