https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69036
Bug ID: 69036
Summary: g++ hangs compiling tree-ssa-loop-ivopts.c at -O3
Product: gcc
Version: 6.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gary at intrepid dot com
Target Milestone: ---
While trying to build and bootstrap GCC at -O3 (using
--with-build-config=bootstrap-O3) on an x86-64, the compiler hangs in the final
stage while trying to build tree-ssa-loop-ivopts.o. As shown below, the
failure can be triggered by doing a regular bootstrap build and then forcing
the compilation of tree-ssa-loop-ivopts.c at -O3. Interestingly, it does not
replicate _unless_ the compiler is fully bootstrap, which may indicate there is
an issue with GCC (prev-gcc) compiling itself. Also, when the compiler hangs,
it appears that its memory requirement steadily climbs over time.
The first failing version appears to be this one:
r231674 | rguenth | 2015-12-16 01:21:04 -0800 (Wed, 16 Dec 2015) | 8 lines
2015-12-16 Richard Biener <rguent...@suse.de>
PR tree-optimization/68892
* tree-vect-slp.c (vect_analyze_slp_cost_1): Properly compute
cost for permuted loads.
* gcc.dg/vect/bb-slp-pr68892.c: New testcase.
Steps to reproduce.
1. Standard configure and make.
(cd ./src; svn up -q -r231674)
src=`cd src; pwd`
rm -rf bld
mkdir bld
cd bld
$src/configure
nj=`getconf _NPROCESSORS_ONLN`
make -j$nj >& make.log
2. cd into gcc build directory and attempt to remake tree-ssa-loop-ivopts.o at
-O3.
cd gcc
rm tree-ssa-loop-ivopts.o
make CXXFLAGS='-O3 -g' tree-ssa-loop-ivopts.o
[compiler hangs]
