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riscv-gcc-1
Commit ddc8bed2 by Michael Meissner Committed by Michael Meissner
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Do not do src->dest copy if register would not be allocated a normal register 

Co-Authored-By: Jim Wilson <wilson@cygnus.com>

From-SVN: r20512
parent 3bd89472
Showing with 165 additions and 16 deletions
gcc/ChangeLog
Mon Jun 15 13:20:33 1998 Jim Wilson <wilson@cygnus.com>
Mon Jun 15 17:06:43 1998 Michael Meissner <meissner@cygnus.com>
Jim Wilson <wilson@cygnus.com>
* c-decl.c (shadow_tag_warned): Use specs not declspecs in for loop.
* regmove.c (copy_src_to_dest): Do not copy src to dest if either
the source or destination is special.
Mon Jun 15 15:33:45 1998 Michael Meissner <meissner@cygnus.com>
Mon Jun 15 13:20:33 1998 Jim Wilson <wilson@cygnus.com>
* regmove.c: Undo June 11th change for now.
* c-decl.c (shadow_tag_warned): Use specs not declspecs in for loop.
Mon Jun 15 07:16:29 PDT 1998 Jeff Law (law@cygnus.com)
......
gcc/regmove.c
......@@ -43,11 +43,14 @@ the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "flags.h"
#include "expr.h"
#include "insn-flags.h"
#include "basic-block.h"
static int optimize_reg_copy_1 PROTO((rtx, rtx, rtx));
static void optimize_reg_copy_2 PROTO((rtx, rtx, rtx));
static void optimize_reg_copy_3 PROTO((rtx, rtx, rtx));
static rtx gen_add3_insn PROTO((rtx, rtx, rtx));
static void copy_src_to_dest PROTO((rtx, rtx, rtx, int));
static int *regmove_bb_head;
struct match {
int with[MAX_RECOG_OPERANDS];
......@@ -528,6 +531,105 @@ optimize_reg_copy_3 (insn, dest, src)
validate_replace_rtx (src, src_reg, insn);
}
/* If we were not able to update the users of src to use dest directly, try
instead moving the value to dest directly before the operation. */
void
copy_src_to_dest (insn, src, dest, loop_depth)
rtx insn;
rtx src;
rtx dest;
{
rtx seq;
rtx link;
rtx next;
rtx set;
rtx move_insn;
rtx *p_insn_notes;
rtx *p_move_notes;
int i;
int src_regno;
int dest_regno;
int bb;
int insn_uid;
int move_uid;
/* A REG_LIVE_LENGTH of -1 indicates the register is equivalent to a constant
or memory location and is used infrequently; a REG_LIVE_LENGTH of -2 is
parameter when there is no frame pointer that is not allocated a register.
For now, we just reject them, rather than incrementing the live length. */
if (GET_CODE (src) == REG && GET_CODE (dest) == REG
&& (set = single_set (insn)) != NULL_RTX
&& !reg_mentioned_p (dest, SET_SRC (set))
&& REG_LIVE_LENGTH (REGNO (dest)) > 0
&& REG_LIVE_LENGTH (REGNO (src)) > 0
&& validate_replace_rtx (src, dest, insn))
{
/* Generate the src->dest move. */
start_sequence ();
emit_move_insn (dest, src);
seq = gen_sequence ();
end_sequence ();
emit_insn_before (seq, insn);
move_insn = PREV_INSN (insn);
p_move_notes = &REG_NOTES (move_insn);
p_insn_notes = &REG_NOTES (insn);
/* Move any notes mentioning src to the move instruction */
for (link = REG_NOTES (insn); link != NULL_RTX; link = next)
{
next = XEXP (link, 1);
if (XEXP (link, 0) == src)
{
*p_move_notes = link;
p_move_notes = &XEXP (link, 1);
}
else
{
*p_insn_notes = link;
p_insn_notes = &XEXP (link, 1);
}
}
*p_move_notes = NULL_RTX;
*p_insn_notes = NULL_RTX;
/* Is the insn the head of a basic block? If so extend it */
insn_uid = INSN_UID (insn);
move_uid = INSN_UID (move_insn);
bb = regmove_bb_head[insn_uid];
if (bb >= 0)
{
basic_block_head[bb] = move_insn;
regmove_bb_head[insn_uid] = -1;
}
/* Update the various register tables. */
dest_regno = REGNO (dest);
REG_N_SETS (dest_regno) += loop_depth;
REG_N_REFS (dest_regno) += loop_depth;
REG_LIVE_LENGTH (dest_regno)++;
if (REGNO_FIRST_UID (dest_regno) == insn_uid)
REGNO_FIRST_UID (dest_regno) = move_uid;
src_regno = REGNO (src);
if (! find_reg_note (move_insn, REG_DEAD, src))
REG_LIVE_LENGTH (src_regno)++;
if (REGNO_FIRST_UID (src_regno) == insn_uid)
REGNO_FIRST_UID (src_regno) = move_uid;
if (REGNO_LAST_UID (src_regno) == insn_uid)
REGNO_LAST_UID (src_regno) = move_uid;
if (REGNO_LAST_NOTE_UID (src_regno) == insn_uid)
REGNO_LAST_NOTE_UID (src_regno) = move_uid;
}
}
/* Return whether REG is set in only one location, and is set to a
constant, but is set in a different basic block from INSN (an
instructions which uses REG). In this case REG is equivalent to a
......@@ -750,10 +852,16 @@ regmove_optimize (f, nregs, regmove_dump_file)
struct match match;
int pass;
int maxregnum = max_reg_num (), i;
rtx copy_src, copy_dst;
regno_src_regno = (int *)alloca (sizeof *regno_src_regno * maxregnum);
for (i = maxregnum; --i >= 0; ) regno_src_regno[i] = -1;
regmove_bb_head = (int *)alloca (sizeof (int) * (get_max_uid () + 1));
for (i = get_max_uid (); --i >= 0; ) regmove_bb_head[i] = -1;
for (i = 0; i < n_basic_blocks; i++)
regmove_bb_head[INSN_UID (basic_block_head[i])] = i;
/* A forward/backward pass. Replace output operands with input operands. */
loop_depth = 1;
......@@ -936,6 +1044,7 @@ regmove_optimize (f, nregs, regmove_dump_file)
{
int insn_code_number = find_matches (insn, &match);
int operand_number, match_number;
int success = 0;
if (insn_code_number < 0)
continue;
......@@ -946,13 +1055,14 @@ regmove_optimize (f, nregs, regmove_dump_file)
operand. If safe, then replace the source operand with the
dest operand in both instructions. */
copy_src = NULL_RTX;
copy_dst = NULL_RTX;
for (operand_number = 0;
operand_number < insn_n_operands[insn_code_number];
operand_number++)
{
rtx set, p, src, dst;
rtx src_note, dst_note;
int success = 0;
int num_calls = 0;
enum reg_class src_class, dst_class;
int length;
......@@ -1016,27 +1126,58 @@ regmove_optimize (f, nregs, regmove_dump_file)
|| CLASS_LIKELY_SPILLED_P (src_class))
&& (! reg_class_subset_p (dst_class, src_class)
|| CLASS_LIKELY_SPILLED_P (dst_class)))
continue;
if (! (src_note = find_reg_note (insn, REG_DEAD, src)))
continue;
{
if (!copy_src)
{
copy_src = src;
copy_dst = dst;
}
continue;
}
/* Can not modify an earlier insn to set dst if this insn
uses an old value in the source. */
if (reg_overlap_mentioned_p (dst, SET_SRC (set)))
continue;
{
if (!copy_src)
{
copy_src = src;
copy_dst = dst;
}
continue;
}
if (! (src_note = find_reg_note (insn, REG_DEAD, src)))
{
if (!copy_src)
{
copy_src = src;
copy_dst = dst;
}
continue;
}
if (regmove_dump_file)
fprintf (regmove_dump_file,
"Could fix operand %d of insn %d matching operand %d.\n",
operand_number, INSN_UID (insn), match_number);
/* If src is set once in a different basic block,
and is set equal to a constant, then do not use
it for this optimization, as this would make it
no longer equivalent to a constant. */
if (reg_is_remote_constant_p (src, insn, f))
continue;
if (reg_is_remote_constant_p (src, insn, f))
{
if (!copy_src)
{
copy_src = src;
copy_dst = dst;
}
continue;
}
if (regmove_dump_file)
fprintf (regmove_dump_file,
"Could fix operand %d of insn %d matching operand %d.\n",
operand_number, INSN_UID (insn), match_number);
/* Scan backward to find the first instruction that uses
the input operand. If the operand is set here, then
......@@ -1173,6 +1314,12 @@ regmove_optimize (f, nregs, regmove_dump_file)
break;
}
}
/* If we weren't able to replace any of the alternatives, try an
alternative appoach of copying the source to the destination. */
if (!success && copy_src != NULL_RTX)
copy_src_to_dest (insn, copy_src, copy_dst, loop_depth);
}
}
#endif /* REGISTER_CONSTRAINTS */
......
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