Hi,
this patch fixes PR65818, and hppa bootstrap.
When compiling gcc/libiberty/vprintf-support.c, the following va_arg is
compiled:
...
(void) __builtin_va_arg(ap, double);
...
This results in the following ifn_va_arg at gimple level, with a NULL_TREE lhs:
...
VA_ARG (&ap, 0B);
...
We start expanding the ifn_va_arg in expand_ifn_va_arg_1 by calling
gimplify_va_arg_internal:
...
expr = gimplify_va_arg_internal (ap, type, gimple_location (stmt),
&pre, &post);
...
Subsequently, because the lhs is NULL_TREE, we skip generating the assign to the
lhs:
...
lhs = gimple_call_lhs (stmt);
if (lhs != NULL_TREE)
{
gcc_assert (useless_type_conversion_p (TREE_TYPE (lhs), type));
if (gimple_call_num_args (stmt) == 3)
{
/* We've transported the size of with WITH_SIZE_EXPR here as
the 3rd argument of the internal fn call. Now reinstate
it. */
tree size = gimple_call_arg (stmt, 2);
expr = build2 (WITH_SIZE_EXPR, TREE_TYPE (expr), expr, size);
}
/* We use gimplify_assign here, rather than gimple_build_assign,
because gimple_assign knows how to deal with variable-sized
types. */
gimplify_assign (lhs, expr, &pre);
}
...
We assume here that any side-effects related to updating ap have been generated
into pre/post by gimplify_va_arg_internal, and that it's safe to ignore expr.
Turns out, that's not the case for hppa. The target hook
hppa_gimplify_va_arg_expr (called from gimplify_va_arg_internal) returns an
expression that still contains a side-effect:
...
*(double *) (ap = ap + 4294967288 & 4294967288B)
...
This patch fixes that by gimplifying the address expression of the mem-ref
returned by the target hook (borrowing code from gimplify_expr, case MEM_REF).
Bootstrapped and reg-tested on x86_64.
Bootstrapped and reg-tested on hppa2.0w-hp-hpux11.11.
OK for trunk?
Thanks,
- Tom
Return side-effect free result in gimplify_va_arg_internal
2015-04-22 Tom de Vries <t...@codesourcery.com>
PR tree-optimization/65818
* gimplify.c (gimplify_va_arg_internal): Ensure that only side-effect
free values are returned.
---
gcc/gimplify.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index c68bd47..fe54e53 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -9352,7 +9352,12 @@ gimplify_va_arg_internal (tree valist, tree type, location_t loc,
else
gimplify_expr (&valist, pre_p, post_p, is_gimple_min_lval, fb_lvalue);
- return targetm.gimplify_va_arg_expr (valist, type, pre_p, post_p);
+ tree expr = targetm.gimplify_va_arg_expr (valist, type, pre_p, post_p);
+ gcc_assert (TREE_CODE (expr) == MEM_REF);
+ if (!is_gimple_mem_ref_addr (TREE_OPERAND (expr, 0)))
+ gimplify_expr (&TREE_OPERAND (expr, 0), pre_p, post_p,
+ is_gimple_mem_ref_addr, fb_rvalue);
+ return expr;
}
/* Gimplify __builtin_va_arg, aka VA_ARG_EXPR, which is not really a
--
1.9.1
