re PR libgomp/84086 ([8 Regresssion] segfault in instantiate_scev_r for…

re PR libgomp/84086 ([8 Regresssion] segfault in instantiate_scev_r for libgomp.fortran/examples-4/simd-2.f90 -O1)

2018-01-29  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/84086
	* tree-ssanames.c: Include cfgloop.h and tree-scalar-evolution.h.
	(flush_ssaname_freelist): When SSA names were released reset
	the SCEV hash table.

From-SVN: r257152

gcc/ChangeLog

 2018-01-29  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/84086
+	* tree-ssanames.c: Include cfgloop.h and tree-scalar-evolution.h.
+	(flush_ssaname_freelist): When SSA names were released reset
+	the SCEV hash table.
+
+2018-01-29  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/84057
 	* tree-ssa-loop-ivcanon.c (unloop_loops): Deal with already
 	removed paths when removing edges.

gcc/tree-ssanames.c

@@ -29,6 +29,8 @@ along with GCC; see the file COPYING3.  If not see
 #include "stor-layout.h"
 #include "tree-into-ssa.h"
 #include "tree-ssa.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
 
 /* Rewriting a function into SSA form can create a huge number of SSA_NAMEs,
    many of which may be thrown away shortly after their creation if jumps
@@ -241,6 +243,9 @@ verify_ssaname_freelists (struct function *fun)
 void
 flush_ssaname_freelist (void)
 {
+  /* If there were any SSA names released reset the SCEV cache.  */
+  if (! vec_safe_is_empty (FREE_SSANAMES_QUEUE (cfun)))
+    scev_reset_htab ();
   vec_safe_splice (FREE_SSANAMES (cfun), FREE_SSANAMES_QUEUE (cfun));
   vec_safe_truncate (FREE_SSANAMES_QUEUE (cfun), 0);
 }