On Wed, Apr 20, 2016 at 07:43:27AM -0700, H.J. Lu wrote: > From 12c6ddcf67593ed7137764ca74043f1a9c2d8fda Mon Sep 17 00:00:00 2001 > From: "H.J. Lu" <hjl.to...@gmail.com> > Date: Wed, 30 Mar 2016 05:56:08 -0700 > Subject: [PATCH 2/3] Don't build 32-bit libgomp with -march=i486 on x86-64 > > Gcc uses the same -march= for both -m32 and -m64 on x86-64 unless > --with-arch-32= is used. There is no need for -march=i486 to compile > 32-bit libgomp on x86-64. > > PR target/70454 > * configure.tgt (XCFLAGS): Don't add -march=i486 to compile > 32-bit target library on x86-64.
That is wrong. It could be --with-arch-32=i386 build. If you really want to find out the ISA reliably, just run ${CC} ${CFLAGS} -E -dD -xc /dev/null and get through all the cases, or try to compile a testcase with some __atomic* builtin in it and see if it results in a call or not. > --- > libgomp/configure.tgt | 10 ++-------- > 1 file changed, 2 insertions(+), 8 deletions(-) > > diff --git a/libgomp/configure.tgt b/libgomp/configure.tgt > index 77e73f0..c290080 100644 > --- a/libgomp/configure.tgt > +++ b/libgomp/configure.tgt > @@ -79,16 +79,10 @@ if test x$enable_linux_futex = xyes; then > esac > ;; > > - # Similar jiggery-pokery for x86_64 multilibs, except here we > - # can't rely on the --with-arch configure option, since that > - # applies to the 64-bit side. > x86_64-*-linux*) > config_path="linux/x86 linux posix" > - case " ${CC} ${CFLAGS} " in > - *" -m32 "*) > - XCFLAGS="${XCFLAGS} -march=i486 -mtune=generic" > - ;; > - esac > + # x86_64 compiler passes -march=x86_64 by default when building > + # 32bit target libraries. > ;; > > # Note that sparcv7 and sparcv8 is not included here. We need cas. > -- > 2.5.5 > Jakub