[PATCH] Fix PR64853

[Richard Biener]

This fixes PR64853 by restricting what we lookup from 
match-and-simplifiers further in propagator engine using passes.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2015-01-29  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/64853
        * tree-vrp.c (vrp_valueize_1): Do not return anything if the
        stmt will get simulated again.
        * tree-ssa-ccp.c (valueize_op_1): Likewise.

        * gcc.dg/torture/pr64853.c: New testcase.

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c      (revision 220235)
+++ gcc/tree-vrp.c      (working copy)
@@ -7092,15 +7092,15 @@ vrp_valueize_1 (tree name)
 {
   if (TREE_CODE (name) == SSA_NAME)
     {
-      value_range_t *vr = get_value_range (name);
-      if (range_int_cst_singleton_p (vr))
-       return vr->min;
       /* If the definition may be simulated again we cannot follow
          this SSA edge as the SSA propagator does not necessarily
         re-visit the use.  */
       gimple def_stmt = SSA_NAME_DEF_STMT (name);
       if (prop_simulate_again_p (def_stmt))
        return NULL_TREE;
+      value_range_t *vr = get_value_range (name);
+      if (range_int_cst_singleton_p (vr))
+       return vr->min;
     }
   return name;
 }
Index: gcc/tree-ssa-ccp.c
===================================================================
--- gcc/tree-ssa-ccp.c  (revision 220235)
+++ gcc/tree-ssa-ccp.c  (working copy)
@@ -1141,15 +1141,15 @@ valueize_op_1 (tree op)
 {
   if (TREE_CODE (op) == SSA_NAME)
     {
-      tree tem = get_constant_value (op);
-      if (tem)
-       return tem;
       /* If the definition may be simulated again we cannot follow
          this SSA edge as the SSA propagator does not necessarily
         re-visit the use.  */
       gimple def_stmt = SSA_NAME_DEF_STMT (op);
       if (prop_simulate_again_p (def_stmt))
        return NULL_TREE;
+      tree tem = get_constant_value (op);
+      if (tem)
+       return tem;
     }
   return op;
 }
Index: gcc/testsuite/gcc.dg/torture/pr64853.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr64853.c      (revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr64853.c      (working copy)
@@ -0,0 +1,44 @@
+/* { dg-do run } */
+
+struct S
+{
+  int f1;
+};
+
+static struct S a = { 1 };
+char b;
+static unsigned char *c = &b;
+int d, e, f;
+
+int
+fn1 (int p)
+{
+  return 0 ? 0 : p - 1;
+}
+
+static int
+fn2 (struct S p)
+{
+  int g = 200;
+  for (e = 4; e; e = fn1 (e))
+    {
+      for (; d; d++)
+       ;
+      *c &= p.f1 & g;
+      g = --*c;
+      if (f)
+       return 0;
+    }
+  return 0;
+}
+
+int
+main ()
+{
+  fn2 (a);
+
+  if (b != 0) 
+    __builtin_abort (); 
+
+  return 0;
+}