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[Bug target/78460] [7/8 Regression] [SH] OOM building glibc string tst-cmp.c
- From: "jsm28 at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 15 Aug 2017 23:43:09 +0000
- Subject: [Bug target/78460] [7/8 Regression] [SH] OOM building glibc string tst-cmp.c
- Auto-submitted: auto-generated
- References: <bug-78460-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78460
--- Comment #6 from Joseph S. Myers <jsm28 at gcc dot gnu.org> ---
Author: jsm28
Date: Tue Aug 15 23:42:23 2017
New Revision: 251108
URL: https://gcc.gnu.org/viewcvs?rev=251108&root=gcc&view=rev
Log:
Limit SH strncmp inline expansion (PR target/78460).
GCC mainline built for sh4-linux-gnu runs out of memory building a
glibc test, which calls strncmp with very large constant size
argument, resulting in the SH inline strncmp expansion trying to
inline a fully unrolled expansion of strncmp for that size.
This patch limits that fully unrolled expansion to the case of less
than 32 bytes. This is explicitly *not* trying to be optimal in any
way (very likely a lower threshold makes sense), just to limit enough
to avoid the out-of-memory issue in the glibc testsuite.
I have *not* run the GCC testsuite for SH. I have verified that this
allows the glibc testsuite to build OK, with both GCC mainline and GCC
7 branch (and that the included test builds quickly with patched GCC,
runs out of memory with unpatched GCC).
PR target/78460
PR target/67712
gcc:
* config/sh/sh-mem.cc (sh_expand_cmpnstr): Only unroll for
constant count if that count is less than 32.
gcc/testsuite:
* gcc.c-torture/compile/string-large-1.c: New test.
Added:
trunk/gcc/testsuite/gcc.c-torture/compile/string-large-1.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/config/sh/sh-mem.cc
trunk/gcc/testsuite/ChangeLog