[Bug rtl-optimization/78583] [7 Regression] ICE on valid C code at -O3 on x86_64-linux-gnu (internal compiler error: in simplify_truncation)

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78583

--- Comment #2 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Wed Nov 30 08:41:26 2016
New Revision: 243000

URL: https://gcc.gnu.org/viewcvs?rev=243000&root=gcc&view=rev
Log:
simplify-rtx: Add missing line for previous commit (PR78583)

The comment for the added case to simplify_truncation reads

  /* Turn (truncate:M1 (*_extract:M2 (reg:M2) (len) (pos))) into
     (*_extract:M1 (truncate:M1 (reg:M2)) (len) (pos')) if possible without
     changing len.  */

but I forgot to check the two modes M2 are actually the same.


        PR rtl-optimization/78583
        * simplify-rtx.c (simplify_truncation): Add check missing from the
        previous commit.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/simplify-rtx.c