[Bug tree-optimization/79351] [7/8/9 Regression] Invalid tree PRE optimization around compound literal

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79351

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Wed Nov 28 11:01:06 2018
New Revision: 266551

URL: https://gcc.gnu.org/viewcvs?rev=266551&root=gcc&view=rev
Log:
2018-11-28  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/79351
        * tree-ssa-sccvn.c (vn_reference_lookup_3): For assignments from
        empty CONSTRUCTORs ensure the store is at a constant position.

        * gcc.dg/torture/pr79351.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr79351.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-ssa-sccvn.c