[Bug tree-optimization/87977] New: [9 Regression] ICE: verify_ssa failed (error: definition in block 4 follows the use)

["asolokha at gmx dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87977

            Bug ID: 87977
           Summary: [9 Regression] ICE: verify_ssa failed (error:
                    definition in block 4 follows the use)
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: asolokha at gmx dot com
  Target Milestone: ---

gcc-9.0.0-alpha20181111 snapshot (r266019) ICEs when compiling
gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c w/ -g -O1 (-O2, -O3, -Ofast, -Os)
-funsafe-math-optimizations:

% gcc-9.0.0-alpha20181111 -g -O1 -funsafe-math-optimizations -c
gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c
gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c: In function 'foo':
gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c:5:1: error: definition in block 4
follows the use
    5 | foo (double a)
      | ^~~
for SSA_NAME: tmp_5 in statement:
# DEBUG tmp => tmp_5
during GIMPLE pass: recip
gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c:5:1: internal compiler error:
verify_ssa failed
0xeea763 verify_ssa(bool, bool)
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181111/work/gcc-9-20181111/gcc/tree-ssa.c:1188
0xc04e8d execute_function_todo
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181111/work/gcc-9-20181111/gcc/passes.c:1932
0xc05c8e execute_todo
       
/var/tmp/portage/sys-devel/gcc-9.0.0_alpha20181111/work/gcc-9-20181111/gcc/passes.c:1979