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(get_last_value_validate): New argument insn.

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Add check for memory reference clobbered by later store.
(record_value_for_reg, get_last_values): Pass in new argument.

From-SVN: r13900
This commit is contained in:
Jim Wilson 1997-04-14 11:46:37 -07:00
parent ba325ebaef
commit 9a893315ea
1 changed files with 21 additions and 7 deletions
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28
gcc/combine.c
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@ -445,7 +445,7 @@ static void update_table_tick PROTO((rtx));
static void record_value_for_reg PROTO((rtx, rtx, rtx));
static void record_dead_and_set_regs_1 PROTO((rtx, rtx));
static void record_dead_and_set_regs PROTO((rtx));
static int get_last_value_validate PROTO((rtx *, int, int));
static int get_last_value_validate PROTO((rtx *, rtx, int, int));
static rtx get_last_value PROTO((rtx));
static int use_crosses_set_p PROTO((rtx, int));
static void reg_dead_at_p_1 PROTO((rtx, rtx));
@ -10203,11 +10203,12 @@ record_value_for_reg (reg, insn, value)
/* The value being assigned might refer to X (like in "x++;"). In that
case, we must replace it with (clobber (const_int 0)) to prevent
infinite loops. */
if (value && ! get_last_value_validate (&value,
if (value && ! get_last_value_validate (&value, insn,
reg_last_set_label[regno], 0))
{
value = copy_rtx (value);
if (! get_last_value_validate (&value, reg_last_set_label[regno], 1))
if (! get_last_value_validate (&value, insn,
reg_last_set_label[regno], 1))
value = 0;
}
@ -10328,8 +10329,9 @@ record_dead_and_set_regs (insn)
we don't know exactly what registers it was produced from. */
static int
get_last_value_validate (loc, tick, replace)
get_last_value_validate (loc, insn, tick, replace)
rtx *loc;
rtx insn;
int tick;
int replace;
{
@ -10359,10 +10361,20 @@ get_last_value_validate (loc, tick, replace)
return 1;
}
/* If this is a memory reference, make sure that there were
no stores after it that might have clobbered the value. We don't
have alias info, so we assume any store invalidates it. */
else if (GET_CODE (x) == MEM && ! RTX_UNCHANGING_P (x)
&& INSN_CUID (insn) <= mem_last_set)
{
if (replace)
*loc = gen_rtx (CLOBBER, GET_MODE (x), const0_rtx);
return replace;
}
for (i = 0; i < len; i++)
if ((fmt[i] == 'e'
&& get_last_value_validate (&XEXP (x, i), tick, replace) == 0)
&& get_last_value_validate (&XEXP (x, i), insn, tick, replace) == 0)
/* Don't bother with these. They shouldn't occur anyway. */
|| fmt[i] == 'E')
return 0;
@ -10459,14 +10471,16 @@ get_last_value (x)
}
/* If the value has all its registers valid, return it. */
if (get_last_value_validate (&value, reg_last_set_label[regno], 0))
if (get_last_value_validate (&value, reg_last_set[regno],
reg_last_set_label[regno], 0))
return value;
/* Otherwise, make a copy and replace any invalid register with
(clobber (const_int 0)). If that fails for some reason, return 0. */
value = copy_rtx (value);
if (get_last_value_validate (&value, reg_last_set_label[regno], 1))
if (get_last_value_validate (&value, reg_last_set[regno],
reg_last_set_label[regno], 1))
return value;
return 0;