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(find_dummy_reload): New parameter earlyclobber.

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(find_dummy_reload): New parameter earlyclobber.  If set then don't
use IN for the reload if it also appears elsewhere in the insn.  All
callers changed.

From-SVN: r13795
This commit is contained in:
Richard Kenner 1997-03-25 14:27:59 -05:00
parent 03dda8e3c3
commit 189086f974
1 changed files with 19 additions and 7 deletions
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26
gcc/reload.c
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@ -317,7 +317,7 @@ static void push_replacement PROTO((rtx *, int, enum machine_mode));
static void combine_reloads PROTO((void));
static rtx find_dummy_reload PROTO((rtx, rtx, rtx *, rtx *,
enum machine_mode, enum machine_mode,
enum reg_class, int));
enum reg_class, int, int));
static int earlyclobber_operand_p PROTO((rtx));
static int hard_reg_set_here_p PROTO((int, int, rtx));
static struct decomposition decompose PROTO((rtx));
@ -1379,7 +1379,8 @@ push_reload (in, out, inloc, outloc, class,
{
reload_reg_rtx[i] = find_dummy_reload (in, out, inloc, outloc,
inmode, outmode,
reload_reg_class[i], i);
reload_reg_class[i], i,
reload_earlyclobbers[i] != NULL);
/* If the outgoing register already contains the same value
as the incoming one, we can dispense with loading it.
@ -1689,16 +1690,22 @@ combine_reloads ()
to be computed, clear out reload_out[FOR_REAL].
If FOR_REAL is -1, this should not be done, because this call
is just to see if a register can be found, not to find and install it. */
is just to see if a register can be found, not to find and install it.
EARLYCLOBBER is non-zero if OUT is an earlyclobber operand. This
puts an additional constraint on being able to use IN for OUT since
IN must not appear elsewhere in the insn (it is assumed that IN itself
is safe from the earlyclobber). */
static rtx
find_dummy_reload (real_in, real_out, inloc, outloc,
inmode, outmode, class, for_real)
inmode, outmode, class, for_real, earlyclobber)
rtx real_in, real_out;
rtx *inloc, *outloc;
enum machine_mode inmode, outmode;
enum reg_class class;
int for_real;
int earlyclobber;
{
rtx in = real_in;
rtx out = real_out;
@ -1780,7 +1787,8 @@ find_dummy_reload (real_in, real_out, inloc, outloc,
or if OUT dies in this insn (like the quotient in a divmod insn).
We can't use IN unless it is dies in this insn,
which means we must know accurately which hard regs are live.
Also, the result can't go in IN if IN is used within OUT. */
Also, the result can't go in IN if IN is used within OUT,
or if OUT is an earlyclobber and IN appears elsewhere in the insn. */
if (hard_regs_live_known
&& GET_CODE (in) == REG
&& REGNO (in) < FIRST_PSEUDO_REGISTER
@ -1801,7 +1809,10 @@ find_dummy_reload (real_in, real_out, inloc, outloc,
if (! refers_to_regno_for_reload_p (regno, regno + nwords, out, NULL_PTR)
&& ! hard_reg_set_here_p (regno, regno + nwords,
PATTERN (this_insn)))
PATTERN (this_insn))
&& (! earlyclobber
|| ! refers_to_regno_for_reload_p (regno, regno + nwords,
PATTERN (this_insn), inloc)))
{
int i;
for (i = 0; i < nwords; i++)
@ -2872,7 +2883,8 @@ find_reloads (insn, replace, ind_levels, live_known, reload_reg_p)
= find_dummy_reload (recog_operand[i], recog_operand[c],
recog_operand_loc[i], recog_operand_loc[c],
operand_mode[i], operand_mode[c],
this_alternative[c], -1);
this_alternative[c], -1,
this_alternative_earlyclobber[c]);
if (value != 0)
losers--;