Skip to content

R
riscv-gcc-1
Commit 64b8935d by Roger Sayle Committed by Roger Sayle
Options

combine.c: Include "output.h" to define dump_file. 


	* combine.c: Include "output.h" to define dump_file.
	(uid_insn_cost, last_insn_cost): New global variables.
	(combine_insn_cost): New function to estimate cost of an insn.
	(combine_validate_cost): New function to determine whether a
	try_combine replacement sequence is cheaper than the original.
	(combine_instructions): Allocate and populate uid_insn_cost
	array at the start of the combine pass, and deallocate it after.
	(try_combine): Check combine_validate_cost to determine whether
	a "recombination" should be rejected as being more expensive.
	* Makefile.in (combine.o): Add dependency upon output.h.

From-SVN: r83908
parent e5ddaa24
Showing with 176 additions and 3 deletions
gcc/ChangeLog
2004-06-30 Roger Sayle <roger@eyesopen.com>
* combine.c: Include "output.h" to define dump_file.
(uid_insn_cost, last_insn_cost): New global variables.
(combine_insn_cost): New function to estimate cost of an insn.
(combine_validate_cost): New function to determine whether a
try_combine replacement sequence is cheaper than the original.
(combine_instructions): Allocate and populate uid_insn_cost
array at the start of the combine pass, and deallocate it after.
(try_combine): Check combine_validate_cost to determine whether
a "recombination" should be rejected as being more expensive.
* Makefile.in (combine.o): Add dependency upon output.h.
2004-06-30 Roger Sayle <roger@eyesopen.com>
* config/rs6000/rs6000.c (rs6000_rtx_costs) <MINUS_EXPR>: Handle
subtractions identically to additions, always COSTS_N_INSNS (1).
......
gcc/Makefile.in
......@@ -1973,9 +1973,10 @@ loop-unroll.o: loop-unroll.c $(CONFIG_H) $(SYSTEM_H) $(RTL_H) $(TM_H) \
dominance.o : dominance.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
hard-reg-set.h $(BASIC_BLOCK_H) et-forest.h
et-forest.o : et-forest.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) et-forest.h alloc-pool.h
combine.o : combine.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) $(FLAGS_H) \
function.h insn-config.h $(INSN_ATTR_H) $(REGS_H) $(EXPR_H) rtlhooks-def.h \
$(BASIC_BLOCK_H) $(RECOG_H) real.h hard-reg-set.h toplev.h $(TM_P_H) $(TREE_H) $(TARGET_H)
combine.o : combine.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(FLAGS_H) function.h insn-config.h $(INSN_ATTR_H) $(REGS_H) $(EXPR_H) \
rtlhooks-def.h $(BASIC_BLOCK_H) $(RECOG_H) real.h hard-reg-set.h \
toplev.h $(TM_P_H) $(TREE_H) $(TARGET_H) output.h
regclass.o : regclass.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
hard-reg-set.h $(FLAGS_H) $(BASIC_BLOCK_H) $(REGS_H) insn-config.h $(RECOG_H) reload.h \
real.h toplev.h function.h output.h $(GGC_H) $(TM_P_H) $(EXPR_H) $(TIMEVAR_H)
......
gcc/combine.c
......@@ -91,6 +91,8 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
#include "toplev.h"
#include "target.h"
#include "rtlhooks-def.h"
/* Include output.h for dump_file. */
#include "output.h"
/* Number of attempts to combine instructions in this function. */
......@@ -282,6 +284,15 @@ static basic_block this_basic_block;
those blocks as starting points. */
static sbitmap refresh_blocks;
/* The following array records the combine_insn_cost for every insn
in the instruction stream. */
static int *uid_insn_cost;
/* Length of the currently allocated uid_insn_cost array. */
static int last_insn_cost;
/* Incremented for each label. */
static int label_tick;
......@@ -504,6 +515,135 @@ do_SUBST_INT (int *into, int newval)
#define SUBST_INT(INTO, NEWVAL) do_SUBST_INT(&(INTO), (NEWVAL))
/* Calculate the rtx_cost of a single instruction. A return value of zero
indicates an instruction without a known cost. */
static int
combine_insn_cost (rtx pat)
{
int i, cost;
rtx set;
/* Extract the single set rtx from the instruction pattern.
We can't use single_set since we only have the pattern. */
if (GET_CODE (pat) == SET)
set = pat;
else if (GET_CODE (pat) == PARALLEL)
{
set = NULL_RTX;
for (i = 0; i < XVECLEN (pat, 0); i++)
{
rtx x = XVECEXP (pat, 0, i);
if (GET_CODE (x) == SET)
{
if (set)
return 0;
set = x;
}
}
if (!set)
return 0;
}
else
return 0;
cost = rtx_cost (SET_SRC (set), SET);
return cost > 0 ? cost : COSTS_N_INSNS (1);
}
/* Subroutine of try_combine. Determine whether the combine replacement
patterns NEWPAT and NEWI2PAT are cheaper according to combine_insn_cost
that the original instruction sequence I1, I2 and I3. Note that I1
and/or NEWI2PAT may be NULL_RTX. This function returns false, if the
costs of all instructions can be estimated, and the replacements are
more expensive than the original sequence. */
static bool
combine_validate_cost (rtx i1, rtx i2, rtx i3, rtx newpat, rtx newi2pat)
{
int i1_cost, i2_cost, i3_cost;
int new_i2_cost, new_i3_cost;
int old_cost, new_cost;
/* Lookup the original combine_insn_costs. */
i2_cost = INSN_UID (i2) <= last_insn_cost
? uid_insn_cost[INSN_UID (i2)] : 0;
i3_cost = INSN_UID (i3) <= last_insn_cost
? uid_insn_cost[INSN_UID (i3)] : 0;
if (i1)
{
i1_cost = INSN_UID (i1) <= last_insn_cost
? uid_insn_cost[INSN_UID (i1)] : 0;
old_cost = (i1_cost > 0 && i2_cost > 0 && i3_cost > 0)
? i1_cost + i2_cost + i3_cost : 0;
}
else
{
old_cost = (i2_cost > 0 && i3_cost > 0) ? i2_cost + i3_cost : 0;
i1_cost = 0;
}
/* Calculate the replacement combine_insn_costs. */
new_i3_cost = combine_insn_cost (newpat);
if (newi2pat)
{
new_i2_cost = combine_insn_cost (newi2pat);
new_cost = (new_i2_cost > 0 && new_i3_cost > 0)
? new_i2_cost + new_i3_cost : 0;
}
else
{
new_cost = new_i3_cost;
new_i2_cost = 0;
}
/* Disallow this recombination if both new_cost and old_cost are
greater than zero, and new_cost is greater than old cost. */
if (!undobuf.other_insn
&& old_cost > 0
&& new_cost > old_cost)
{
if (dump_file)
{
if (i1)
{
fprintf (dump_file,
"rejecting combination of insns %d, %d and %d\n",
INSN_UID (i1), INSN_UID (i2), INSN_UID (i3));
fprintf (dump_file, "original costs %d + %d + %d = %d\n",
i1_cost, i2_cost, i3_cost, old_cost);
}
else
{
fprintf (dump_file,
"rejecting combination of insns %d and %d\n",
INSN_UID (i2), INSN_UID (i3));
fprintf (dump_file, "original costs %d + %d = %d\n",
i2_cost, i3_cost, old_cost);
}
if (newi2pat)
{
fprintf (dump_file, "replacement costs %d + %d = %d\n",
new_i2_cost, new_i3_cost, new_cost);
}
else
fprintf (dump_file, "replacement cost %d\n", new_cost);
}
return false;
}
/* Update the uid_insn_cost array with the replacement costs. */
uid_insn_cost[INSN_UID (i2)] = new_i2_cost;
uid_insn_cost[INSN_UID (i3)] = new_i3_cost;
if (i1)
uid_insn_cost[INSN_UID (i1)] = 0;
return true;
}
/* Main entry point for combiner. F is the first insn of the function.
NREGS is the first unused pseudo-reg number.
......@@ -568,6 +708,10 @@ combine_instructions (rtx f, unsigned int nregs)
refresh_blocks = sbitmap_alloc (last_basic_block);
sbitmap_zero (refresh_blocks);
/* Allocate array of current combine_insn_costs. */
uid_insn_cost = xcalloc (max_uid_cuid + 1, sizeof (int));
last_insn_cost = max_uid_cuid;
for (insn = f, i = 0; insn; insn = NEXT_INSN (insn))
{
uid_cuid[INSN_UID (insn)] = ++i;
......@@ -586,6 +730,12 @@ combine_instructions (rtx f, unsigned int nregs)
set_nonzero_bits_and_sign_copies (XEXP (links, 0), NULL_RTX,
NULL);
#endif
/* Record the current combine_insn_cost of this instruction. */
uid_insn_cost[INSN_UID (insn)] = combine_insn_cost (PATTERN (insn));
if (dump_file)
fprintf(dump_file, "insn_cost %d: %d\n",
INSN_UID (insn), uid_insn_cost[INSN_UID (insn)]);
}
if (GET_CODE (insn) == CODE_LABEL)
......@@ -762,6 +912,7 @@ combine_instructions (rtx f, unsigned int nregs)
/* Clean up. */
sbitmap_free (refresh_blocks);
free (uid_insn_cost);
free (reg_stat);
free (uid_cuid);
......@@ -2504,6 +2655,14 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
}
#endif
/* Only allow this combination if combine_insn_costs reports that the
replacement instructions are cheaper than the originals. */
if (!combine_validate_cost (i1, i2, i3, newpat, newi2pat))
{
undo_all ();
return 0;
}
/* We now know that we can do this combination. Merge the insns and
update the status of registers and LOG_LINKS. */
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment