[PATCH] Fix PR52402

[Richard Guenther]

This fixes PR52402 in a similar way as PR50444.  IPA SRA needs to be
careful about alignment when constructing accesses.

Bootstrap and regtest pending on x86_64, any comments?

Thanks,
Richard.

2012-02-27  Richard Guenther  <rguent...@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.

Index: gcc/ipa-prop.c
===================================================================
*** gcc/ipa-prop.c      (revision 184591)
--- gcc/ipa-prop.c      (working copy)
*************** ipa_modify_call_arguments (struct cgraph
*** 2508,2516 ****
                }
            }
  
!         expr = fold_build2_loc (loc, MEM_REF, adj->type, base, off);
!         if (adj->by_ref)
!           expr = build_fold_addr_expr (expr);
  
          expr = force_gimple_operand_gsi (&gsi, expr,
                                           adj->by_ref
--- 2508,2534 ----
                }
            }
  
!         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
Index: gcc/testsuite/gcc.dg/torture/pr52402.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr52402.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr52402.c      (revision 0)
***************
*** 0 ****
--- 1,28 ----
+ /* { 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;
+ }