[PATCH] Fix compile-time regression with new VN

[Richard Biener]

When installing the new VN I forgot to update DOM fast queries
before running it from PRE.

Bootstrap / regtest running on x86_64-unknown-linux-gnu, will
install to trunk and branch.

It doesn't solve the PR in full which is about a regression from
GCC 7 - working on that.

Richard.

2019-05-03  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/90316
        * tree-ssa-pre.c (pass_pre::execute): Re-compute DOM fast queries
        before running VN.

Index: gcc/tree-ssa-pre.c
===================================================================
--- gcc/tree-ssa-pre.c  (revision 270842)
+++ gcc/tree-ssa-pre.c  (working copy)
@@ -4197,6 +4197,7 @@ pass_pre::execute (function *fun)
   loop_optimizer_init (LOOPS_NORMAL);
   split_critical_edges ();
   scev_initialize ();
+  calculate_dominance_info (CDI_DOMINATORS);
 
   run_rpo_vn (VN_WALK);