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sibcall.c (return_value_pseudo): New static variable.

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* sibcall.c (return_value_pseudo): New static variable.
	(skip_copy_to_return_value): Handle return_value_pseudo.
	(call_ends_block_p): Ensure that return_value_pseudo is set.
	(optimize_sibling_and_tail_recursive_call): Discover the
	load of pseudo return value in alternate exit block.

From-SVN: r44723
This commit is contained in:
Jan Hubicka 2001-08-08 21:09:11 +02:00 committed by Jan Hubicka
parent 9d98f8f9c4
commit a4b07e7ff8
2 changed files with 47 additions and 1 deletions
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8
gcc/ChangeLog
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@ -1,3 +1,11 @@
Wed Aug 8 21:08:14 CEST 2001 Jan Hubicka <jh@suse.cz>
* sibcall.c (return_value_pseudo): New static variable.
(skip_copy_to_return_value): Handle return_value_pseudo.
(call_ends_block_p): Ensure that return_value_pseudo is set.
(optimize_sibling_and_tail_recursive_call): Discover the
load of pseudo return value in alternate exit block.
Wed Aug 8 21:06:43 CEST 2001 Jan Hubicka <jh@suse.cz>
* calls.c (ECF_ALWAYS_RETURN): New constant.

40
gcc/sibcall.c
View File

@ -32,6 +32,11 @@ Boston, MA 02111-1307, USA. */
#include "output.h"
#include "except.h"
/* In case alternate_exit_block contains copy from pseudo, to return value,
record the pseudo here. In such case the pseudo must be set to function
return in the sibcall sequence. */
static rtx return_value_pseudo;
static int identify_call_return_value PARAMS ((rtx, rtx *, rtx *));
static rtx skip_copy_to_return_value PARAMS ((rtx));
static rtx skip_use_of_return_value PARAMS ((rtx, enum rtx_code));
@ -152,6 +157,13 @@ skip_copy_to_return_value (orig_insn)
if (! set)
return orig_insn;
if (return_value_pseudo)
{
if (SET_DEST (set) == return_value_pseudo)
return insn;
return orig_insn;
}
/* The destination must be the same as the called function's return
value to ensure that any return value is put in the same place by the
current function and the function we're calling.
@ -323,6 +335,7 @@ call_ends_block_p (insn, end)
rtx insn;
rtx end;
{
rtx new_insn;
/* END might be a note, so get the last nonnote insn of the block. */
end = next_nonnote_insn (PREV_INSN (end));
@ -333,7 +346,15 @@ call_ends_block_p (insn, end)
/* Skip over copying from the call's return value pseudo into
this function's hard return register and if that's the end
of the block, we're OK. */
insn = skip_copy_to_return_value (insn);
new_insn = skip_copy_to_return_value (insn);
/* In case we return value in pseudo, we must set the pseudo to
return value of called function, otherwise we are returning
something else. */
if (return_value_pseudo && insn == new_insn)
return 0;
insn = new_insn;
if (insn == end)
return 1;
@ -575,6 +596,8 @@ optimize_sibling_and_tail_recursive_calls ()
if (n_basic_blocks == 0)
return;
return_value_pseudo = NULL_RTX;
/* Find the exit block.
It is possible that we have blocks which can reach the exit block
@ -595,6 +618,7 @@ optimize_sibling_and_tail_recursive_calls ()
insn;
insn = NEXT_INSN (insn))
{
rtx set;
/* This should only happen once, at the start of this block. */
if (GET_CODE (insn) == CODE_LABEL)
continue;
@ -606,6 +630,18 @@ optimize_sibling_and_tail_recursive_calls ()
&& GET_CODE (PATTERN (insn)) == USE)
continue;
/* Exit block also may contain copy from pseudo containing
return value to hard register. */
if (GET_CODE (insn) == INSN
&& (set = single_set (insn))
&& SET_DEST (set) == current_function_return_rtx
&& REG_P (SET_SRC (set))
&& !return_value_pseudo)
{
return_value_pseudo = SET_SRC (set);
continue;
}
break;
}
@ -614,6 +650,8 @@ optimize_sibling_and_tail_recursive_calls ()
valid alternate exit block. */
if (insn == NULL)
alternate_exit = e->src;
else
return_value_pseudo = NULL;
}
/* If the function uses ADDRESSOF, we can't (easily) determine