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re PR target/29090 (gcc.dg-struct-layout-1 failures on Darwin PPC at -m64)

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PR target/29090
	* config/rs6000/rs6000.c (rs6000_gimplify_va_arg): Special-case the
	Darwin64 ABI, for zero-sized objects.

From-SVN: r162568
This commit is contained in:
Iain Sandoe 2010-07-27 13:26:34 +00:00
parent a9ab25e2b4
commit 4b316a1e8b
1 changed files with 44 additions and 0 deletions
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44
gcc/config/rs6000/rs6000.c
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@ -8995,6 +8995,50 @@ rs6000_gimplify_va_arg (tree valist, tree type, gimple_seq *pre_p,
return build_va_arg_indirect_ref (t);
}
/* We need to deal with the fact that the darwin ppc64 ABI is defined by an
earlier version of gcc, with the property that it always applied alignment
adjustments to the va-args (even for zero-sized types). The cheapest way
to deal with this is to replicate the effect of the part of
std_gimplify_va_arg_expr that carries out the align adjust, for the case
of relevance.
We don't need to check for pass-by-reference because of the test above.
We can return a simplifed answer, since we know there's no offset to add. */
if (TARGET_MACHO
&& rs6000_darwin64_abi
&& integer_zerop (TYPE_SIZE (type)))
{
unsigned HOST_WIDE_INT align, boundary;
tree valist_tmp = get_initialized_tmp_var (valist, pre_p, NULL);
align = PARM_BOUNDARY / BITS_PER_UNIT;
boundary = FUNCTION_ARG_BOUNDARY (TYPE_MODE (type), type);
if (boundary > MAX_SUPPORTED_STACK_ALIGNMENT)
boundary = MAX_SUPPORTED_STACK_ALIGNMENT;
boundary /= BITS_PER_UNIT;
if (boundary > align)
{
tree t ;
/* This updates arg ptr by the amount that would be necessary
to align the zero-sized (but not zero-alignment) item. */
t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
fold_build2 (POINTER_PLUS_EXPR,
TREE_TYPE (valist),
valist_tmp, size_int (boundary - 1)));
gimplify_and_add (t, pre_p);
t = fold_convert (sizetype, valist_tmp);
t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist_tmp,
fold_convert (TREE_TYPE (valist),
fold_build2 (BIT_AND_EXPR, sizetype, t,
size_int (-boundary))));
t = build2 (MODIFY_EXPR, TREE_TYPE (valist), valist, t);
gimplify_and_add (t, pre_p);
}
/* Since it is zero-sized there's no increment for the item itself. */
valist_tmp = fold_convert (build_pointer_type (type), valist_tmp);
return build_va_arg_indirect_ref (valist_tmp);
}
if (DEFAULT_ABI != ABI_V4)
{
if (targetm.calls.split_complex_arg && TREE_CODE (type) == COMPLEX_TYPE)