https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78061
Bug ID: 78061 Summary: -O3 causes "Error: definition in block 117 does not dominate use in block 164" Product: gcc Version: 7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: fortran Assignee: unassigned at gcc dot gnu.org Reporter: dcb314 at hotmail dot com Target Milestone: --- Created attachment 39861 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39861&action=edit fortran source code The attached Fortran code, when compiled by gfortran dated 20161021, and compiler flag -O3, does this: $ ../results/bin/gfortran -c -O3 bug315.f bug315.f:190:0: SUBROUTINE SSYMM(SIDE,UPLO,M,N,ALPHA,A,LDA,B,LDB,BETA,C,LDC) Error: definition in block 117 does not dominate use in block 164 for SSA_NAME: .MEM_671 in statement: .MEM_500 = PHI <.MEM_280(161), .MEM_671(164)> PHI argument .MEM_671 for PHI node .MEM_500 = PHI <.MEM_280(161), .MEM_671(164)> bug315.f:190:0: internal compiler error: verify_ssa failed 0xf395ba verify_ssa(bool, bool) ../../trunk/gcc/tree-ssa.c:1158 0xe864c0 rewrite_into_loop_closed_ssa_1(bitmap_head*, unsigned int, int, loop*) ../../trunk/gcc/tree-ssa-loop-manip.c:625 0xe9b6de split_loop ../../trunk/gcc/tree-ssa-loop-split.c:572 0xe9b6de tree_ssa_split_loops ../../trunk/gcc/tree-ssa-loop-split.c:624 0xe9b6de execute ../../trunk/gcc/tree-ssa-loop-split.c:678 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. Source code compiles fine with -O2 $ ../results/bin/gfortran -c -O2 bug315.f $ I'll have a go at trying to reduce it.