re PR tree-optimization/52402 (IPA-SRA creates aligned loads from unaligned memory)

2012-02-28  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/52402
	* ipa-prop.c (ipa_modify_call_arguments): Properly use
	mis-aligned types when creating the accesses at the call site.

	* gcc.dg/torture/pr52402.c: New testcase.

From-SVN: r184619

gcc/ChangeLog

+2012-02-28  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/52402
+	* ipa-prop.c (ipa_modify_call_arguments): Properly use
+	mis-aligned types when creating the accesses at the call site.
+
 2012-02-28  Georg-Johann Lay  <avr@gjlay.de>
 
 	* config/avr/builtins.def: New file.

gcc/ipa-prop.c

@@ -2508,9 +2508,27 @@ ipa_modify_call_arguments (struct cgraph_edge *cs, gimple stmt,
 		}
 	    }
 
-	  expr = fold_build2_loc (loc, MEM_REF, adj->type, base, off);
-	  if (adj->by_ref)
-	    expr = build_fold_addr_expr (expr);
+	  if (!adj->by_ref)
+	    {
+	      tree type = adj->type;
+	      unsigned int align;
+	      unsigned HOST_WIDE_INT misalign;
+	      align = get_pointer_alignment_1 (base, &misalign);
+	      misalign += (double_int_sext (tree_to_double_int (off),
+					    TYPE_PRECISION (TREE_TYPE (off))).low
+			   * BITS_PER_UNIT);
+	      misalign = misalign & (align - 1);
+	      if (misalign != 0)
+		align = (misalign & -misalign);
+	      if (align < TYPE_ALIGN (type))
+		type = build_aligned_type (type, align);
+	      expr = fold_build2_loc (loc, MEM_REF, type, base, off);
+	    }
+	  else
+	    {
+	      expr = fold_build2_loc (loc, MEM_REF, adj->type, base, off);
+	      expr = build_fold_addr_expr (expr);
+	    }
 
 	  expr = force_gimple_operand_gsi (&gsi, expr,
 					   adj->by_ref

gcc/testsuite/ChangeLog

 2012-02-28  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/52402
+	* gcc.dg/torture/pr52402.c: New testcase.
+
+2012-02-28  Richard Guenther  <rguenther@suse.de>
+
 	PR lto/52400
 	* g++.dg/lto/pr52400_0.C: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr52402.c

+/* { dg-do run } */
+
+typedef int v4si __attribute__((vector_size(16)));
+struct T { v4si i[2]; int j; } __attribute__((packed));
+
+static v4si __attribute__((noinline))
+foo (struct T t)
+{
+  return t.i[0];
+}
+
+static struct T *__attribute__((noinline))
+init ()
+{
+  char *p = __builtin_malloc (sizeof (struct T) + 1);
+  p++;
+  __builtin_memset (p, 1, sizeof (struct T));
+  return (struct T *)p;
+}
+
+int main()
+{
+  struct T *p;
+  p = init ();
+  if (foo (*p)[0] != 0x01010101)
+    __builtin_abort ();
+  return 0;
+}