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loop.c (note_set_pseudo_multiple_uses_retval): New variable.

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* loop.c (note_set_pseudo_multiple_uses_retval): New variable.
        (note_set_pseudo_multiple_uses): New function.
        (check_dbra_loop): Use not_set_pseudo_multiple_uses to determine
        if a pseudo set in the loop exit is used elsewhere.

From-SVN: r30155
This commit is contained in:
Jeffrey A Law 1999-10-25 06:44:04 +00:00 • committed by Jeff Law
parent f9c4f105d5
commit 5948776913
2 changed files with 57 additions and 4 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
Mon Oct 25 00:42:35 1999 Jeffrey A Law (law@cygnus.com)
* loop.c (note_set_pseudo_multiple_uses_retval): New variable.
(note_set_pseudo_multiple_uses): New function.
(check_dbra_loop): Use not_set_pseudo_multiple_uses to determine
if a pseudo set in the loop exit is used elsewhere.
Sun Oct 24 20:52:40 1999 Mark Mitchell <mark@codesourcery.com>
* i386.md (mulsi3): Tweak to work with SCO OSR5 COFF assembler.

54
gcc/loop.c
View file

@ -269,6 +269,9 @@ static struct movable *the_movables;
FILE *loop_dump_stream;
/* For communicating return values from note_set_pseudo_multiple_uses. */
static int note_set_pseudo_multiple_uses_retval;
/* Forward declarations. */
static void verify_dominator PROTO((int));
@ -283,6 +286,7 @@ static void count_one_set PROTO((rtx, rtx, varray_type, rtx *));
static void count_loop_regs_set PROTO((rtx, rtx, varray_type, varray_type,
int *, int));
static void note_addr_stored PROTO((rtx, rtx));
static void note_set_pseudo_multiple_uses PROTO((rtx, rtx));
static int loop_reg_used_before_p PROTO((rtx, rtx, rtx, rtx, rtx));
static void scan_loop PROTO((rtx, rtx, rtx, int, int));
#if 0
@ -3172,6 +3176,36 @@ note_addr_stored (x, y)
loop_store_mems = gen_rtx_EXPR_LIST (VOIDmode, x, loop_store_mems);
}
/* X is a value modified by an INSN that references a biv inside a loop
exit test (ie, X is somehow related to the value of the biv). If X
is a pseudo that is used more than once, then the biv is (effectively)
used more than once. */
static void
note_set_pseudo_multiple_uses (x, y)
rtx x;
rtx y ATTRIBUTE_UNUSED;
{
if (x == 0)
return;
while (GET_CODE (x) == STRICT_LOW_PART
|| GET_CODE (x) == SIGN_EXTRACT
|| GET_CODE (x) == ZERO_EXTRACT
|| GET_CODE (x) == SUBREG)
x = XEXP (x, 0);
if (GET_CODE (x) != REG || REGNO (x) < FIRST_PSEUDO_REGISTER)
return;
/* If we do not have usage information, or if we know the register
is used more than once, note that fact for check_dbra_loop. */
if (REGNO (x) >= max_reg_before_loop
|| ! VARRAY_RTX (reg_single_usage, REGNO (x))
|| VARRAY_RTX (reg_single_usage, REGNO (x)) == const0_rtx)
note_set_pseudo_multiple_uses_retval = 1;
}
/* Return nonzero if the rtx X is invariant over the current loop.
@ -7932,10 +7966,22 @@ check_dbra_loop (loop_end, insn_count, loop_start, loop_info)
&& REGNO (SET_DEST (set)) == bl->regno)
/* An insn that sets the biv is okay. */
;
else if (p == prev_nonnote_insn (prev_nonnote_insn (loop_end))
|| p == prev_nonnote_insn (loop_end))
/* Don't bother about the end test. */
;
else if ((p == prev_nonnote_insn (prev_nonnote_insn (loop_end))
|| p == prev_nonnote_insn (loop_end))
&& reg_mentioned_p (bivreg, PATTERN (p)))
{
/* If either of these insns uses the biv and sets a pseudo
that has more than one usage, then the biv has uses
other than counting since it's used to derive a value
that is used more than one time. */
note_set_pseudo_multiple_uses_retval = 0;
note_stores (PATTERN (p), note_set_pseudo_multiple_uses);
if (note_set_pseudo_multiple_uses_retval)
{
no_use_except_counting = 0;
break;
}
}
else if (reg_mentioned_p (bivreg, PATTERN (p)))
{
no_use_except_counting = 0;