https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71352
Bug ID: 71352 Summary: ICE at -O1 and above on x86_64-linux-gnu: in zero_one_operation, at tree-ssa-reassoc.c:1251 Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: su at cs dot ucdavis.edu Target Milestone: --- The following code causes an ICE when compiled with the current gcc trunk at -O1 and above on x86_64-linux-gnu in both 32-bit and 64-bit modes. It is a regression from 6.1.x. This may be related to PR 71230 and PR 71263, but they have been fixed. $ gcc-trunk -v Using built-in specs. COLLECT_GCC=gcc-trunk COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto --prefix=/usr/local/gcc-trunk --disable-bootstrap Thread model: posix gcc version 7.0.0 20160530 (experimental) [trunk revision 236873] (GCC) $ $ gcc-trunk -O0 -c small.c $ gcc-6.1 -O1 -c small.c $ $ gcc-trunk -O1 -c small.c small.c: In function ‘fn1’: small.c:4:1: internal compiler error: in zero_one_operation, at tree-ssa-reassoc.c:1251 fn1 () ^~~ 0xd6d0de zero_one_operation ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:1250 0xd755b2 undistribute_ops_list ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:1604 0xd762a8 reassociate_bb ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:5261 0xd75dc7 reassociate_bb ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:5391 0xd78943 do_reassoc ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:5505 0xd78943 execute_reassoc ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:5592 0xd78943 execute ../../gcc-source-trunk/gcc/tree-ssa-reassoc.c:5631 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <http://gcc.gnu.org/bugs.html> for instructions. $ -------------------------------- unsigned a, b, c, d, e; void fn1 () { unsigned f; e = f = d * -b + a * -c; }