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dse.c (struct insn_info): Add 'frame_read' field.

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* dse.c (struct insn_info): Add 'frame_read' field.
	(scan_insn): For the call to a const function, set frame_read if
	reload has been run.
	If the insn reads the frame, kill the frame related stores.
	(scan_reads_nospill): Likewise.

From-SVN: r129312
This commit is contained in:
Eric Botcazou 2007-10-15 09:41:28 +02:00 committed by Eric Botcazou
parent 2a19b1a9c7
commit 64520bdc18
2 changed files with 68 additions and 3 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
2007-10-15 Eric Botcazou <ebotcazou@libertysurf.fr>
* dse.c (struct insn_info): Add 'frame_read' field.
(scan_insn): For the call to a const function, set frame_read if
reload has been run.
If the insn reads the frame, kill the frame related stores.
(scan_reads_nospill): Likewise.
2007-10-14 Jason Merrill <jason@redhat.com>
* tree-eh.c (optimize_double_finally): Don't assume that the

63
gcc/dse.c
View File

@ -286,8 +286,26 @@ struct insn_info
/* This field is only used for the processing of const functions.
These functions cannot read memory, but they can read the stack
because that is where they may get their parms. It is set to
true if the insn may contain a stack pointer based store. */
because that is where they may get their parms. We need to be
this conservative because, like the store motion pass, we don't
consider CALL_INSN_FUNCTION_USAGE when processing call insns.
Moreover, we need to distinguish two cases:
1. Before reload (register elimination), the stores related to
outgoing arguments are stack pointer based and thus deemed
of non-constant base in this pass. This requires special
handling but also means that the frame pointer based stores
need not be killed upon encountering a const function call.
2. After reload, the stores related to outgoing arguments can be
either stack pointer or hard frame pointer based. This means
that we have no other choice than also killing all the frame
pointer based stores upon encountering a const function call.
This field is set after reload for const function calls. Having
this set is less severe than a wild read, it just means that all
the frame related stores are killed rather than all the stores. */
bool frame_read;
/* This field is only used for the processing of const functions.
It is set if the insn may contain a stack pointer based store. */
bool stack_pointer_based;
/* This is true if any of the sets within the store contains a
@ -1967,10 +1985,36 @@ scan_insn (bb_info_t bb_info, rtx insn)
if (dump_file)
fprintf (dump_file, "const call %d\n", INSN_UID (insn));
/* See the head comment of the frame_read field. */
if (reload_completed)
insn_info->frame_read = true;
/* Loop over the active stores and remove those which are
killed by the const function call. */
while (i_ptr)
{
/* Remove the stack pointer based stores. */
bool remove_store = false;
/* The stack pointer based stores are always killed. */
if (i_ptr->stack_pointer_based)
remove_store = true;
/* If the frame is read, the frame related stores are killed. */
else if (insn_info->frame_read)
{
store_info_t store_info = i_ptr->store_rec;
/* Skip the clobbers. */
while (!store_info->is_set)
store_info = store_info->next;
if (store_info->group_id >= 0
&& VEC_index (group_info_t, rtx_group_vec,
store_info->group_id)->frame_related)
remove_store = true;
}
if (remove_store)
{
if (dump_file)
dump_insn_info ("removing from active", i_ptr);
@ -1982,6 +2026,7 @@ scan_insn (bb_info_t bb_info, rtx insn)
}
else
last = i_ptr;
i_ptr = i_ptr->next_local_store;
}
}
@ -2491,6 +2536,18 @@ scan_reads_nospill (insn_info_t insn_info, bitmap gen, bitmap kill)
int i;
group_info_t group;
/* If this insn reads the frame, kill all the frame related stores. */
if (insn_info->frame_read)
{
for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++)
if (group->process_globally && group->frame_related)
{
if (kill)
bitmap_ior_into (kill, group->group_kill);
bitmap_and_compl_into (gen, group->group_kill);
}
}
while (read_info)
{
for (i = 0; VEC_iterate (group_info_t, rtx_group_vec, i, group); i++)