[Bug rtl-optimization/87874] [8/9 Regression] ICE in simplify_subreg, at simplify-rtx.c:6396

[aoliva at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87874

--- Comment #5 from Alexandre Oliva <aoliva at gcc dot gnu.org> ---
Author: aoliva
Date: Wed Nov  7 06:25:30 2018
New Revision: 265860

URL: https://gcc.gnu.org/viewcvs?rev=265860&root=gcc&view=rev
Log:
[PR87874] avoid const-wide-int subreg in LRA

Just like CONST_INT, CONST_WIDE_INT is VOIDmode, so LRA might be
tempted to build a SUBREG to "convert" it to the wanted mode.  That's
no use.  Test for CONST_SCALAR_INT_P instead of CONST_INT_P so that we
skip the subreg creation for both.

for  gcc/ChangeLog

        PR rtl-optimization/87874
        * lra.c (lra_substitute_pseudo): Do not create a subreg for
        const wide ints.

for  gcc/testsuite/ChangeLog

        PR rtl-optimization/87874
        * gcc.dg/pr87874.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/pr87874.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/lra.c
    trunk/gcc/testsuite/ChangeLog