re PR tree-optimization/56799 (Runfail after r197060+r197082.)

        PR tree-optimization/56799
        * tree-ssa-dom.c (record_equivalences_from_incoming_edge): Bring
        back test for widening conversion erroneously dropped in prior
        change.

        PR tree-optimization/56799
        * gcc.c-torture/execute/pr56799.c: New test.

From-SVN: r197453

gcc/ChangeLog

+2013-04-03  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/56799
+        * tree-ssa-dom.c (record_equivalences_from_incoming_edge): Bring
+	back test for widening conversion erroneously dropped in prior
+	change.
+
 2013-04-03  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	PR target/56809
@@ -896,6 +903,7 @@
 	* config/tilegx/tilepro.h (PROFILE_BEFORE_PROLOGUE): Define.
 
 2013-03-25  Jeff Law  <law@redhat.com>
+
         * tree-ssa-dom.c (record_equivalences_from_incoming_edge): Add missing
         check for INTEGRAL_TYPE_P that was missing due to checking in
 	wrong version of prior patch.

gcc/testsuite/ChangeLog

+2013-04-03  Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/56799
+	* gcc.c-torture/execute/pr56799.c: New test.
+
 2013-04-03  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/56815

gcc/testsuite/gcc.c-torture/execute/pr56799.c

+
+#include <stdio.h>
+typedef struct { int x; int y;} S;
+extern int foo(S*);
+int hi = 0, lo = 0;
+
+int main()
+{
+  S a;
+  int r;
+  a.x = (int) 0x00010000;
+  a.y = 1;
+  r = foo (&a);
+  if (r == 2 && lo==0 && hi==1)
+    {
+      exit (0);
+    }
+  abort ();
+}
+
+typedef unsigned short u16;
+
+__attribute__ ((noinline)) int foo (S* ptr)
+{
+  int a = ptr->x;
+  int c = 0;
+  u16 b = (u16) a;
+  if (b != 0)
+  {
+    lo = 1;
+    c += ptr->y;
+  }
+  b = a >> 16;
+  if (b != 0)
+  {
+    hi = 1;
+    c+= ptr->y;
+  }
+  c += ptr->y;
+  return c;
+}
+
+     

gcc/tree-ssa-dom.c

@@ -1151,9 +1151,15 @@ record_equivalences_from_incoming_edge (basic_block bb)
 		{
 		  tree old_rhs = gimple_assign_rhs1 (defstmt);
 
-		  /* If the constant is in the range of the type of OLD_RHS,
-		     then convert the constant and record the equivalence.  */
+		  /* If the conversion widens the original value and
+		     the constant is in the range of the type of OLD_RHS,
+		     then convert the constant and record the equivalence. 
+
+		     Note that int_fits_type_p does not check the precision
+		     if the upper and lower bounds are OK.  */
 		  if (INTEGRAL_TYPE_P (TREE_TYPE (old_rhs))
+		      && (TYPE_PRECISION (TREE_TYPE (lhs))
+			  > TYPE_PRECISION (TREE_TYPE (old_rhs)))
 		      && int_fits_type_p (rhs, TREE_TYPE (old_rhs)))
 		    {
 		      tree newval = fold_convert (TREE_TYPE (old_rhs), rhs);