This patch adjusts the C frontend to retain array-refs in
address-taking operations instead of expanding them via
pointer arithmetic. As seen in PR48571 we can't re-construct
array-refs in the middle-end, thus we should keep information
as specified by the source level.
For
int a[10];
int *foo (int i)
{
return &a[i];
}
int *bar (int i)
{
return &i[a];
}
this will now emit
return &a[i];
instead of
return (int *) &a + (long unsigned int) ((long unsigned int) i * 4);
which is also shorter.
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Ok for trunk?
Thanks,
Richard.
2011-04-14 Richard Guenther <rguent...@suse.de>
* c-typeck.c (build_unary_op): Do not expand array-refs via
pointer arithmetic. Only adjust qualifiers for function types.
Index: gcc/c-typeck.c
===================================================================
--- gcc/c-typeck.c (revision 172319)
+++ gcc/c-typeck.c (working copy)
@@ -3737,12 +3737,6 @@ build_unary_op (location_t location,
tree op0 = TREE_OPERAND (arg, 0);
if (!c_mark_addressable (op0))
return error_mark_node;
- return build_binary_op (location, PLUS_EXPR,
- (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
- ? array_to_pointer_conversion (location,
- op0)
- : op0),
- TREE_OPERAND (arg, 1), 1);
}
/* Anything not already handled and not a true memory reference
@@ -3769,10 +3763,11 @@ build_unary_op (location_t location,
argtype = TREE_TYPE (arg);
/* If the lvalue is const or volatile, merge that into the type
- to which the address will point. This should only be needed
+ to which the address will point. This is only needed
for function types. */
if ((DECL_P (arg) || REFERENCE_CLASS_P (arg))
- && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg)))
+ && (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg))
+ && TREE_CODE (argtype) == FUNCTION_TYPE)
{
int orig_quals = TYPE_QUALS (strip_array_types (argtype));
int quals = orig_quals;
@@ -3782,9 +3777,6 @@ build_unary_op (location_t location,
if (TREE_THIS_VOLATILE (arg))
quals |= TYPE_QUAL_VOLATILE;
- gcc_assert (quals == orig_quals
- || TREE_CODE (argtype) == FUNCTION_TYPE);
-
argtype = c_build_qualified_type (argtype, quals);
}
