Bug 583198 – cross-arm*/gcc: nesting level exceeded when compiling cross compiler for arm with clang

• Status: RESOLVED INVALID
• Product: Gentoo/Alt

[Description Michael Weiser 2016-05-16 16:18:42 UTC]

When compiling gcc as a cross compiler for target arm with clang, I hit bug https://llvm.org/bugs/show_bug.cgi?id=19650:

.../gcc/config/arm/neon.md:3486:10917: fatal error:
     bracket nesting level exceeded maximum of 256
.../gcc/config/arm/neon.md:3486:10917: note: use
     -fbracket-depth=N to increase maximum nesting level

As the linked llvm upsteam bug and gcc mailing list discussion linked from there show, there is some contention who's actually at fault. A quick upstream fix does not seem to be forthcoming. So I changed the ebuild as shown in the attached patch to work around it.

Reproducible: Always

[Comment 1 Michael Weiser 2016-05-16 16:19:21 UTC]

Created attachment 434438 [details, diff]
Make gcc compile as cross compiler for arm using clang

[Comment 2 Michael Weiser 2016-05-16 16:21:01 UTC]

Ah, BTW, I'm not checking for compiling a cross compiler because I expect the same thing to happen when compiling using clang *on* arm for arm.

[Comment 3 Michael Weiser 2016-06-19 23:05:34 UTC]

Please disregard. This does not work. CFLAGS are still reset by toolchain.eclass. You need to set CFLAGS_${CTARGET//-/_}, i.e. CFLAGS_armv7ve_hardfloat_linux_gnueabi="-fbracket-depth=1024", to get them around toolchain's flags cleanliness. I've worked around it using an env snippet now.