2010-09-17 Richard Guenther <rguenther@suse.de>

	PR middle-end/45678
	* builtins.c (fold_builtin_memory_op): Always properly adjust
	alignment of memory accesses.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@164356 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7625ff3..04eeac7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2010-09-17  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/45678
+       * builtins.c (fold_builtin_memory_op): Always properly adjust
+       alignment of memory accesses.
+
 2010-09-16  Jan Hubicka  <jh@suse.cz>
 
        * lto-cgraph.c (input_overwrite_node): Do not set DECL_EXTERNAL when

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 2dd6119..384a81a 100644 (file)
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -8555,12 +8555,21 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
       STRIP_NOPS (srcvar);
       if (TREE_CODE (srcvar) == ADDR_EXPR
          && var_decl_component_p (TREE_OPERAND (srcvar, 0))
-         && tree_int_cst_equal (TYPE_SIZE_UNIT (srctype), len)
-         && (!STRICT_ALIGNMENT
-             || !destvar
-             || src_align >= TYPE_ALIGN (desttype)))
-       srcvar = fold_build2 (MEM_REF, destvar ? desttype : srctype,
-                             srcvar, off0);
+         && tree_int_cst_equal (TYPE_SIZE_UNIT (srctype), len))
+       {
+         if (!destvar
+             || src_align >= TYPE_ALIGN (desttype))
+           srcvar = fold_build2 (MEM_REF, destvar ? desttype : srctype,
+                                 srcvar, off0);
+         else if (!STRICT_ALIGNMENT)
+           {
+             srctype = build_aligned_type (TYPE_MAIN_VARIANT (desttype),
+                                           src_align);
+             srcvar = fold_build2 (MEM_REF, srctype, srcvar, off0);
+           }
+         else
+           srcvar = NULL_TREE;
+       }
       else
        srcvar = NULL_TREE;
 
@@ -8569,19 +8578,31 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
 
       if (srcvar == NULL_TREE)
        {
-         if (STRICT_ALIGNMENT
-             && src_align < TYPE_ALIGN (desttype))
-           return NULL_TREE;
          STRIP_NOPS (src);
-         srcvar = fold_build2 (MEM_REF, desttype, src, off0);
+         if (src_align >= TYPE_ALIGN (desttype))
+           srcvar = fold_build2 (MEM_REF, desttype, src, off0);
+         else
+           {
+             if (STRICT_ALIGNMENT)
+               return NULL_TREE;
+             srctype = build_aligned_type (TYPE_MAIN_VARIANT (desttype),
+                                           src_align);
+             srcvar = fold_build2 (MEM_REF, srctype, src, off0);
+           }
        }
       else if (destvar == NULL_TREE)
        {
-         if (STRICT_ALIGNMENT
-             && dest_align < TYPE_ALIGN (srctype))
-           return NULL_TREE;
          STRIP_NOPS (dest);
-         destvar = fold_build2 (MEM_REF, srctype, dest, off0);
+         if (dest_align >= TYPE_ALIGN (srctype))
+           destvar = fold_build2 (MEM_REF, srctype, dest, off0);
+         else
+           {
+             if (STRICT_ALIGNMENT)
+               return NULL_TREE;
+             desttype = build_aligned_type (TYPE_MAIN_VARIANT (srctype),
+                                            dest_align);
+             destvar = fold_build2 (MEM_REF, desttype, dest, off0);
+           }
        }
 
       expr = build2 (MODIFY_EXPR, TREE_TYPE (destvar), destvar, srcvar);