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reload.c (remove_replacements): New function.

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* reload.c (remove_replacements): New function.
	* reload.h (remove_replacements): Declare.
	* reload1.c (choose_reload_regs): Disable some reloads that
	belong to inherited reloads.

From-SVN: r19735
This commit is contained in:
J"orn Rennecke 1998-05-14 00:44:02 +00:00 committed by Joern Rennecke
parent f824910ea1
commit 029b38ff04
4 changed files with 66 additions and 0 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
Thu May 14 08:41:46 1998 J"orn Rennecke <amylaar@cygnus.co.uk>
* reload.c (remove_replacements): New function.
* reload.h (remove_replacements): Declare.
* reload1.c (choose_reload_regs): Disable some reloads that
belong to inherited reloads.
Thu May 14 02:17:17 1998 J"orn Rennecke <amylaar@cygnus.co.uk>
* reload1.c (merge_assigned_reloads): When merging, reset

15
gcc/reload.c
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@ -1506,6 +1506,21 @@ transfer_replacements (to, from)
replacements[i].what = to;
}
/* Remove all replacements in reload FROM. */
void
remove_replacements (from)
int from;
{
int i, j;
for (i = 0, j = 0; i < n_replacements; i++)
{
if (replacements[i].what == from)
continue;
replacements[j++] = replacements[i];
}
}
/* If there is only one output reload, and it is not for an earlyclobber
operand, try to combine it with a (logically unrelated) input reload
to reduce the number of reload registers needed.

3
gcc/reload.h
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@ -157,6 +157,9 @@ extern void clear_secondary_mem PROTO((void));
reload TO. */
extern void transfer_replacements PROTO((int, int));
/* Remove all replacements in reload FROM. */
extern void remove_replacements PROTO((int));
/* Like rtx_equal_p except that it allows a REG and a SUBREG to match
if they are the same hard reg, and has special hacks for
autoincrement and autodecrement. */

41
gcc/reload1.c
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@ -5799,6 +5799,47 @@ choose_reload_regs (insn, avoid_return_reg)
reload_opnum[r],
reload_when_needed[r]))
reload_inherited[r] = 0;
/* If we can inherit a RELOAD_FOR_INPUT, then we do not need its related
RELOAD_FOR_INPUT_ADDRESS / RELOAD_FOR_INPADDR_ADDRESS reloads.
??? This could be extended to other reload types, but these are
more tricky to handle:
RELOAD_FOR_OTHER_ADDRESS reloads might have been merged, so we
can't eliminate them without a check that *all* references are
now unused due to inheritance.
While RELOAD_FOR_INPADDR_ADDRESS and RELOAD_FOR_OUTADDR_ADDRESS are
not merged, we can't be sure that we have eliminated the use of
that particular reload if we have seen just one
RELOAD_FOR_INPUT_ADDRESS / RELOAD_FOR_OUTPUT_ADDRESS being inherited,
since there might be multiple of the latter two reloads for a single
operand.
RELOAD_FOR_OPADDR_ADDR reloads for different operands are not
merged, but might share the same register by courtesy of
reload_reg_free_for_value_p. reload_reg_used_in_op_addr_reload
does not differentiate by opnum, thus calling clear_reload_reg_in_use
for one of these reloads would mark the register as free even though
another RELOAD_FOR_OPADDR_ADDR reload might still use it. */
else if (reload_inherited[r] && reload_when_needed[r] == RELOAD_FOR_INPUT)
{
for (i = 0; i < n_reloads; i++)
{
if ((reload_when_needed[i] == RELOAD_FOR_INPUT_ADDRESS
|| reload_when_needed[i] == RELOAD_FOR_INPADDR_ADDRESS)
&& reload_opnum[i] == reload_opnum[r]
&& reload_in[i] && reload_reg_rtx[i])
{
int regno = true_regnum (reload_reg_rtx[i]);
reload_in[i] = 0;
if (spill_reg_order[regno] >= 0)
clear_reload_reg_in_use (regno, reload_opnum[i],
reload_when_needed[i],
reload_mode[i]);
reload_reg_rtx[i] = 0;
reload_spill_index[i] = -1;
remove_replacements (i);
}
}
}
/* If we found a better place to reload from,
validate it in the same fashion, if it is a reload reg. */