[Bug tree-optimization/89956] [9 Regression] ICE: Segmentation fault (in gsi_for_stmt(gimple*))

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89956

--- Comment #4 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Author: rsandifo
Date: Fri Apr  5 07:31:12 2019
New Revision: 270162

URL: https://gcc.gnu.org/viewcvs?rev=270162&root=gcc&view=rev
Log:
Make FMA code cope with redundant negates (PR89956)

This patch fixes a case in which, due to forced missed optimisations
in earlier passes, we have:

    _1 = a * b
    _2 = -_1
    _3 = -_1
    _4 = _2 + _3

and treated _4 as two FNMA candidates, once via _2 and once via _3.

2019-04-05  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
        PR tree-optimization/89956
        * tree-ssa-math-opts.c (convert_mult_to_fma): Protect against
        multiple negates of the same value.

gcc/testsuite/
        PR tree-optimization/89956
        * gfortran.dg/pr89956.f90: New test.

Added:
    trunk/gcc/testsuite/gfortran.dg/pr89956.f90
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-math-opts.c