re PR tree-optimization/71039 (ICE: verify_ssa failed (error: definition in…

re PR tree-optimization/71039 (ICE: verify_ssa failed (error: definition in block 4 does not dominate use in block 5) w/ -O1 and above)

2016-05-10  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/71039
	* tree-ssa-phiprop.c: Include tree-ssa-loop.h.
	(chk_uses): New function.
	(propagate_with_phi): Verify we can safely replicate the lhs of an
	aggregate assignment on all incoming edges.

	* gcc.dg/torture/pr71039.c: New testcase.

From-SVN: r236079

gcc/ChangeLog

+2016-05-10  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71039
+	* tree-ssa-phiprop.c: Include tree-ssa-loop.h.
+	(chk_uses): New function.
+	(propagate_with_phi): Verify we can safely replicate the lhs of an
+	aggregate assignment on all incoming edges.
+
 2016-05-10  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	* config/rx/rx-protos.h (is_interrupt_func, is_fast_interrupt_func):

gcc/testsuite/ChangeLog

+2016-05-10  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/71039
+	* gcc.dg/torture/pr71039.c: New testcase.
+
 2016-05-10  Nathan Sidwell  <nathan@acm.org>
 
 	* gcc.dg/nested-func-10.c: Requires alloca.

gcc/testsuite/gcc.dg/torture/pr71039.c

+/* { dg-do compile } */
+
+struct wv
+{
+  int qi;
+} qp, *ft;
+void *pb;
+
+void
+wz (void)
+{
+  struct wv *vf = pb ? (struct wv *)&pb : &qp;
+  *ft = *vf;
+}

gcc/tree-ssa-phiprop.c

@@ -32,6 +32,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "gimplify.h"
 #include "gimple-iterator.h"
 #include "stor-layout.h"
+#include "tree-ssa-loop.h"
 
 /* This pass propagates indirect loads through the PHI node for its
    address to make the load source possibly non-addressable and to
@@ -230,6 +231,19 @@ phiprop_insert_phi (basic_block bb, gphi *phi, gimple *use_stmt,
   return res;
 }
 
+/* Verify if *idx is available at *DATA.  */
+
+static bool
+chk_uses (tree, tree *idx, void *data)
+{
+  basic_block dom = (basic_block) data;
+  if (TREE_CODE (*idx) == SSA_NAME)
+    return (SSA_NAME_IS_DEFAULT_DEF (*idx)
+	    || ! dominated_by_p (CDI_DOMINATORS,
+				 gimple_bb (SSA_NAME_DEF_STMT (*idx)), dom));
+  return true;
+}
+
 /* Propagate between the phi node arguments of PHI in BB and phi result
    users.  For now this matches
         # p_2 = PHI <&x, &y>
@@ -342,6 +356,13 @@ propagate_with_phi (basic_block bb, gphi *phi, struct phiprop_d *phivn,
          insert aggregate copies on the edges instead.  */
       if (!is_gimple_reg_type (TREE_TYPE (TREE_TYPE (ptr))))
 	{
+	  /* As we replicate the lhs on each incoming edge all
+	     used SSA names have to be available there.  */
+	  if (! for_each_index (gimple_assign_lhs_ptr (use_stmt),
+				chk_uses,
+				get_immediate_dominator (CDI_DOMINATORS,
+							 gimple_bb (phi))))
+	    goto next;
 	  phiprop_insert_phi (bb, phi, use_stmt, phivn, n);
 
 	  /* Remove old stmt.  The phi is taken care of by DCE.  */