re PR middle-end/45017 (miscompile with bitfield and optimization)

2010-07-22  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/45017
	* tree-ssa-sccvn.c (vn_reference_eq): Make sure we honor
	TYPE_PRECISION of integral types in addition to size.

	* gcc.c-torture/execute/pr45017.c: New testcase.

From-SVN: r162411

gcc/ChangeLog

+2010-07-22  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/45017
+	* tree-ssa-sccvn.c (vn_reference_eq): Make sure we honor
+	TYPE_PRECISION of integral types in addition to size.
+
 2010-07-22  Maxim Kuvyrkov  <maxim@codesourcery.com>
 
 	* config/rs6000/sysv4.h (CHOOSE_DYNAMIC_LINKER): Default to GLIBC

gcc/testsuite/ChangeLog

+2010-07-22  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/45017
+	* gcc.c-torture/execute/pr45017.c: New testcase.
+
 2010-07-22  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/45019

gcc/testsuite/gcc.c-torture/execute/pr45017.c

+int tester(char *bytes)
+{
+  union {
+      struct {
+	  unsigned int r1:4;
+	  unsigned int r2:4;
+      } fmt;
+      char value[1];
+  } ovl;
+
+  ovl.value[0] = bytes[0];
+  return ovl.fmt.r1;
+}
+extern void abort (void);
+int main()
+{
+  char buff = 0x2f;
+  if (tester(&buff) != 0x0f)
+    abort ();
+  return 0;
+}
+

gcc/tree-ssa-sccvn.c

@@ -498,6 +498,21 @@ vn_reference_eq (const void *p1, const void *p2)
   if (!expressions_equal_p (TYPE_SIZE (vr1->type), TYPE_SIZE (vr2->type)))
     return false;
 
+  if (INTEGRAL_TYPE_P (vr1->type)
+      && INTEGRAL_TYPE_P (vr2->type))
+    {
+      if (TYPE_PRECISION (vr1->type) != TYPE_PRECISION (vr2->type))
+	return false;
+    }
+  else if (INTEGRAL_TYPE_P (vr1->type)
+	   && (TYPE_PRECISION (vr1->type)
+	       != TREE_INT_CST_LOW (TYPE_SIZE (vr1->type))))
+    return false;
+  else if (INTEGRAL_TYPE_P (vr2->type)
+	   && (TYPE_PRECISION (vr2->type)
+	       != TREE_INT_CST_LOW (TYPE_SIZE (vr2->type))))
+    return false;
+
   i = 0;
   j = 0;
   do