[Bug fortran/78061] New: -O3 causes "Error: definition in block 117 does not dominate use in block 164"

[dcb314 at hotmail dot com]

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.