[Bug tree-optimization/92819] [10 Regression] Worse code generated on avx2 due to simplify_vector_constructor

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92819

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Dec  6 07:53:15 2019
New Revision: 279033

URL: https://gcc.gnu.org/viewcvs?rev=279033&root=gcc&view=rev
Log:
2019-12-06  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/92819
        * match.pd (VEC_PERM_EXPR -> BIT_INSERT_EXPR): Handle inserts
        into the last lane.  For two-element vectors try inserting
        into the last lane when inserting into the first fails.

        * gcc.target/i386/pr92819-1.c: New testcase.
        * gcc.target/i386/pr92803.c: Adjust.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr92819-1.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/match.pd
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.target/i386/pr92803.c