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Re: [PATCH] Fix PR rtl-optimization/23585 (delay slots)
- From: Thiemo Seufer <ths at networkno dot de>
- To: Eric Botcazou <ebotcazou at libertysurf dot fr>
- Cc: Ian Lance Taylor <ian at airs dot com>, gcc-patches at gcc dot gnu dot org
- Date: Tue, 1 Nov 2005 18:20:45 +0100
- Subject: Re: [PATCH] Fix PR rtl-optimization/23585 (delay slots)
- References: <200510151826.46512.ebotcazou@libertysurf.fr> <200510162129.38295.ebotcazou@libertysurf.fr> <m3hdbhnsze.fsf@gossamer.airs.com> <200510171227.57814.ebotcazou@libertysurf.fr>
Eric Botcazou wrote:
> > I think I would prefer to see may_trap_p turned into a static
> > may_trap_p_1, with a parameter to replace the file static
> > unaligned_memrefs_trap_p. Other than that, and the aforementioned
> > SPARC_STACK_BOUNDARY_HACK comments, the patch looks OK to me.
>
> Revised version attached. Only exercised on the testcase for now; I'll do a
> complete testing cycle if/when I install it.
>
> > Please wait a day to see if there any other comments, though.
>
> Sure, I'll wait a few days.
>
>
> 2005-10-16 ?Eric Botcazou ?<ebotcazou@libertysurf.fr>
>
> ????????PR rtl-optimization/23585
> ????????* rtlanal.c (rtx_addr_can_trap_p_1): New predicate extracted from...
> ????????(rtx_addr_can_trap_p): ... here. Invoke rtx_addr_can_trap_p_1.
> (may_trap_p_1): New predicate extracted from...
> (may_trap_p): ... here. Invoke (may_trap_p_1.
> ????????(may_trap_or_fault_p): New predicate.
> ????????* rtl.h (may_trap_or_fault_p): Declare it.
> ????????* reorg.c (steal_delay_list_from_target): Use may_trap_or_fault_p
> ????????instead of may_trap_p.
> ????????(steal_delay_list_from_fallthrough): Likewise.
> ????????(fill_simple_delay_slots): Likewise.
> ????????(fill_slots_from_thread): Likewise.
> * function.c (pad_to_arg_alignment): Rework comment about
> SPARC_STACK_BOUNDARY_HACK.
> * config/sparc/sparc.h: Likewise.
This patch breaks (at least) for the latest gcc 4.0 on mips-linux
with the attached testcase:
$ build/gcc/xgcc -Bbuild/gcc -O2 -mabi=64 -c -o testcase testcase.c
testcase.c: In function 'direct2indirect':
testcase.c:57: internal compiler error: Floating point exception
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
For Debian GNU/Linux specific bug reporting instructions,
see <URL:file:///usr/share/doc/gcc-4.0/README.Bugs>.
Reverting this single line of it lets the testcase build successfully.
--- src/gcc/reorg.c.old 2005-09-03 21:09:51.000000000 +0200
+++ src/gcc/reorg.c 2005-10-31 23:16:47.000000000 +0100
@@ -2653,7 +2653,7 @@ fill_slots_from_thread (rtx insn, rtx co
if (!must_annul
&& (condition == const_true_rtx
|| (! insn_sets_resource_p (trial, &opposite_needed, 1)
- && ! may_trap_or_fault_p (pat))))
+ && ! may_trap_p (pat))))
{
old_trial = trial;
trial = try_split (pat, trial, 0);
I don't know if this is a proper fix or only a workaround which happens
to work on mips.
Thiemo
/* gcc -O2 -mabi=64 -c -o foo.o foo.c */
struct offset_v1 {
int k_uniqueness;
};
struct offset_v2 {
long v;
} __attribute__ ((__packed__));
struct reiserfs_key {
int k_objectid;
union {
struct offset_v1 k_offset_v1;
struct offset_v2 k_offset_v2;
} u;
};
struct item_head
{
struct reiserfs_key ih_key;
int ih_version;
};
static void set_offset_v2_k_type(struct offset_v2 *v2)
{
v2->v &= 1;
}
static void set_le_key_k_type (int version, struct reiserfs_key * key)
{
version ? (key->u.k_offset_v1.k_uniqueness = 1)
: set_offset_v2_k_type(&(key->u.k_offset_v2));
}
static void set_le_ih_k_type (struct item_head * ih)
{
set_le_key_k_type((__builtin_constant_p((ih)->ih_version) ? (ih)->ih_version : (ih)->ih_version), &(ih->ih_key));
}
void boo(struct item_head *ih, const char *body);
void direct2indirect(void)
{
struct item_head *p_le_ih;
struct item_head ind_ih;
unsigned int unfm_ptr;
if (__builtin_expect(32, 0)) __asm__ ("break");
set_le_ih_k_type (&ind_ih);
if (__builtin_constant_p(p_le_ih) ? 1 : 2) {
(__builtin_constant_p(__builtin_constant_p(1) == 1));
boo(&ind_ih, (char *)&unfm_ptr);
}
}