/* Move registers around to reduce number of move instructions needed.
- Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc.
+ Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+ 1999, 2000 Free Software Foundation, Inc.
This file is part of GNU CC.
#include "insn-config.h"
#include "recog.h"
#include "output.h"
-#include "reload.h"
#include "regs.h"
#include "hard-reg-set.h"
#include "flags.h"
#include "basic-block.h"
#include "toplev.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 perhaps_ends_bb_p PARAMS ((rtx));
+static int optimize_reg_copy_1 PARAMS ((rtx, rtx, rtx));
+static void optimize_reg_copy_2 PARAMS ((rtx, rtx, rtx));
+static void optimize_reg_copy_3 PARAMS ((rtx, rtx, rtx));
+static rtx gen_add3_insn PARAMS ((rtx, rtx, rtx));
+static void copy_src_to_dest PARAMS ((rtx, rtx, rtx, int));
static int *regmove_bb_head;
struct match {
int early_clobber[MAX_RECOG_OPERANDS];
};
-static rtx discover_flags_reg PROTO((void));
-static void mark_flags_life_zones PROTO((rtx));
-static void flags_set_1 PROTO((rtx, rtx, void *));
+static rtx discover_flags_reg PARAMS ((void));
+static void mark_flags_life_zones PARAMS ((rtx));
+static void flags_set_1 PARAMS ((rtx, rtx, void *));
-static int try_auto_increment PROTO((rtx, rtx, rtx, rtx, HOST_WIDE_INT, int));
-static int find_matches PROTO((rtx, struct match *));
-static int fixup_match_1 PROTO((rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *))
+static int try_auto_increment PARAMS ((rtx, rtx, rtx, rtx, HOST_WIDE_INT, int));
+static int find_matches PARAMS ((rtx, struct match *));
+static int fixup_match_1 PARAMS ((rtx, rtx, rtx, rtx, rtx, int, int, int, FILE *))
;
-static int reg_is_remote_constant_p PROTO((rtx, rtx, rtx));
-static int stable_and_no_regs_but_for_p PROTO((rtx, rtx, rtx));
-static int regclass_compatible_p PROTO((int, int));
-static int replacement_quality PROTO((rtx));
-static int fixup_match_2 PROTO((rtx, rtx, rtx, rtx, FILE *));
+static int reg_is_remote_constant_p PARAMS ((rtx, rtx, rtx));
+static int stable_and_no_regs_but_for_p PARAMS ((rtx, rtx, rtx));
+static int regclass_compatible_p PARAMS ((int, int));
+static int replacement_quality PARAMS ((rtx));
+static int fixup_match_2 PARAMS ((rtx, rtx, rtx, rtx, FILE *));
/* Return non-zero if registers with CLASS1 and CLASS2 can be merged without
causing too much register allocation problems. */
alive, death, birth. This lets more important info
overwrite the mode of lesser info. */
- if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ if (INSN_P (insn))
{
#ifdef HAVE_cc0
/* In the cc0 case, death is not marked in reg notes,
when the registers get tied. */
return 2;
}
+\f
+/* Return 1 if INSN might end a basic block. */
+
+static int perhaps_ends_bb_p (insn)
+ rtx insn;
+{
+ switch (GET_CODE (insn))
+ {
+ case CODE_LABEL:
+ case JUMP_INSN:
+ /* These always end a basic block. */
+ return 1;
+
+ case CALL_INSN:
+ /* A CALL_INSN might be the last insn of a basic block, if it is inside
+ an EH region or if there are nonlocal gotos. Note that this test is
+ very conservative. */
+ return flag_exceptions || nonlocal_goto_handler_labels;
+ default:
+ /* All others never end a basic block. */
+ return 0;
+ }
+}
+\f
/* INSN is a copy from SRC to DEST, both registers, and SRC does not die
in INSN.
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it is inside
- an EH region. There is no easy way to tell, so we just always break
- when we see a CALL_INSN if flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
+ the register lifetime info (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
break;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ else if (! INSN_P (p))
continue;
if (reg_set_p (src, p) || reg_set_p (dest, p)
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it is inside
- an EH region. There is no easy way to tell, so we just always break
- when we see a CALL_INSN if flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
+ the register lifetime info (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
break;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ else if (! INSN_P (p))
continue;
set = single_set (p);
/* Set to stop at next insn. */
for (q = insn; q != NEXT_INSN (p); q = NEXT_INSN (q))
- if (GET_RTX_CLASS (GET_CODE (q)) == 'i')
+ if (INSN_P (q))
{
if (reg_mentioned_p (dest, PATTERN (q)))
PATTERN (q) = replace_rtx (PATTERN (q), dest, src);
|| REG_N_SETS (src_no) != 1)
return;
for (p = PREV_INSN (insn); p && ! reg_set_p (src_reg, p); p = PREV_INSN (p))
- {
- if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- return;
+ /* ??? We can't scan past the end of a basic block without updating
+ the register lifetime info (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
+ break;
- /* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it is inside
- an EH region. There is no easy way to tell, so we just always break
- when we see a CALL_INSN if flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
- return;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
- continue;
- }
if (! p)
return;
subreg = gen_rtx_SUBREG (old_mode, src_reg, 0);
while (p = NEXT_INSN (p), p != insn)
{
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ if (! INSN_P (p))
continue;
/* Make a tenative change. */
if (GET_CODE (src) == REG
&& REG_LIVE_LENGTH (REGNO (src)) > 0
&& GET_CODE (dest) == REG
+ && !RTX_UNCHANGING_P (dest)
&& REG_LIVE_LENGTH (REGNO (dest)) > 0
&& (set = single_set (insn)) != NULL_RTX
&& !reg_mentioned_p (dest, SET_SRC (set))
{
rtx s;
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ if (! INSN_P (p))
continue;
s = single_set (p);
if (s != 0
{
rtx pset;
- if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it is inside
- an EH region. There is no easy way to tell, so we just always break
- when we see a CALL_INSN if flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
+ the register lifetime info (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
break;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ else if (! INSN_P (p))
continue;
if (find_regno_note (p, REG_DEAD, REGNO (dst)))
for (p = PREV_INSN (insn); p; p = PREV_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
+ || GET_CODE (p) == JUMP_INSN)
break;
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ if (! INSN_P (p))
continue;
if (reg_overlap_mentioned_p (dst, PATTERN (p)))
{
for (p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
+ || GET_CODE (p) == JUMP_INSN)
break;
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ if (! INSN_P (p))
continue;
if (reg_overlap_mentioned_p (dst, PATTERN (p)))
{
continue;
if (match.early_clobber[match_no]
- && count_occurrences (PATTERN (insn), src) > 1)
+ && count_occurrences (PATTERN (insn), src, 0) > 1)
continue;
/* Make sure match_operand is the destination. */
for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
{
- if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
+ if (INSN_P (insn))
{
int op_no, match_no;
int success = 0;
continue;
if (match.early_clobber[match_no]
- && count_occurrences (PATTERN (insn), src) > 1)
+ && count_occurrences (PATTERN (insn), src, 0) > 1)
continue;
/* Make sure match_no is the destination. */
{
rtx pset;
- if (GET_CODE (p) == CODE_LABEL
- || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without
updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if
- it is inside an EH region. There is no easy way to tell,
- so we just always break when we see a CALL_INSN if
- flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
+ (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
break;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ else if (! INSN_P (p))
continue;
length++;
DST is operand number MATCH_NUMBER in INSN.
If BACKWARD is nonzero, we have been called in a backward pass.
Return nonzero for success. */
+
static int
fixup_match_1 (insn, set, src, src_subreg, dst, backward, operand_number,
match_number, regmove_dump_file)
int success = 0;
int num_calls = 0, s_num_calls = 0;
enum rtx_code code = NOTE;
- HOST_WIDE_INT insn_const, newconst;
+ HOST_WIDE_INT insn_const = 0, newconst;
rtx overlap = 0; /* need to move insn ? */
- rtx src_note = find_reg_note (insn, REG_DEAD, src), dst_note;
+ rtx src_note = find_reg_note (insn, REG_DEAD, src), dst_note = NULL_RTX;
int length, s_length;
/* If SRC is marked as unchanging, we may not change it.
for (length = s_length = 0, p = NEXT_INSN (insn); p; p = NEXT_INSN (p))
{
- if (GET_CODE (p) == CODE_LABEL || GET_CODE (p) == JUMP_INSN
- || (GET_CODE (p) == NOTE
- && (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it is
- inside an EH region. There is no easy way to tell, so we just
- always break when we see a CALL_INSN if flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (p) == CALL_INSN)
+ the register lifetime info (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (p))
break;
-
- if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ else if (! INSN_P (p))
continue;
length++;
if (! src_note)
{
rtx q;
- rtx set2;
+ rtx set2 = NULL_RTX;
/* If an optimization is done, the value of SRC while P
is executed will be changed. Check that this is OK. */
break;
for (q = p; q; q = NEXT_INSN (q))
{
- if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN
- || (GET_CODE (q) == NOTE
- && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END)))
- {
- q = 0;
- break;
- }
-
/* ??? We can't scan past the end of a basic block without
updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if
- it is inside an EH region. There is no easy way to tell,
- so we just always break when we see a CALL_INSN if
- flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (q) == CALL_INSN)
+ (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (q))
{
q = 0;
break;
}
-
- if (GET_RTX_CLASS (GET_CODE (q)) != 'i')
+ else if (! INSN_P (q))
continue;
- if (reg_overlap_mentioned_p (src, PATTERN (q))
- || reg_set_p (src, q))
+ else if (reg_overlap_mentioned_p (src, PATTERN (q))
+ || reg_set_p (src, q))
break;
}
if (q)
/* Reject out of range shifts. */
if (code != PLUS
&& (newconst < 0
- || (newconst
- >= GET_MODE_BITSIZE (GET_MODE (SET_SRC (set2))))))
+ || ((unsigned HOST_WIDE_INT) newconst
+ >= (GET_MODE_BITSIZE (GET_MODE
+ (SET_SRC (set2)))))))
break;
if (code == PLUS)
{
/* emit_insn_after_with_line_notes has no
return value, so search for the new insn. */
insn = p;
- while (GET_RTX_CLASS (GET_CODE (insn)) != 'i'
- || PATTERN (insn) != pat)
+ while (! INSN_P (insn) || PATTERN (insn) != pat)
insn = PREV_INSN (insn);
REG_NOTES (insn) = notes;
if (! overlap && (code == PLUS || code == MINUS))
{
rtx note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
- rtx q, set2;
+ rtx q, set2 = NULL_RTX;
int num_calls2 = 0, s_length2 = 0;
if (note && CONSTANT_P (XEXP (note, 0)))
{
for (q = PREV_INSN (insn); q; q = PREV_INSN(q))
{
- if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN
- || (GET_CODE (q) == NOTE
- && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END)))
- {
- q = 0;
- break;
- }
-
/* ??? We can't scan past the end of a basic block without
updating the register lifetime info
- (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if
- it is inside an EH region. There is no easy way to tell,
- so we just always break when we see a CALL_INSN if
- flag_exceptions is nonzero. */
- if (flag_exceptions && GET_CODE (q) == CALL_INSN)
+ (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (q))
{
q = 0;
break;
}
-
- if (GET_RTX_CLASS (GET_CODE (q)) != 'i')
+ else if (! INSN_P (q))
continue;
+
s_length2++;
if (reg_set_p (src, q))
{
inc_dest = post_inc_set ? SET_DEST (post_inc_set) : src;
for (q = post_inc; (q = NEXT_INSN (q)); )
{
- if (GET_CODE (q) == CODE_LABEL || GET_CODE (q) == JUMP_INSN
- || (GET_CODE (q) == NOTE
- && (NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (q) == NOTE_INSN_LOOP_END)))
- break;
-
/* ??? We can't scan past the end of a basic block without updating
- the register lifetime info (REG_DEAD/basic_block_live_at_start).
- A CALL_INSN might be the last insn of a basic block, if it
- is inside an EH region. There is no easy way to tell so we
- just always break when we see a CALL_INSN if flag_exceptions
- is nonzero. */
- if (flag_exceptions && GET_CODE (q) == CALL_INSN)
+ the register lifetime info
+ (REG_DEAD/basic_block_live_at_start). */
+ if (perhaps_ends_bb_p (q))
break;
-
- if (GET_RTX_CLASS (GET_CODE (q)) != 'i')
+ else if (! INSN_P (q))
continue;
- if (src != inc_dest && (reg_overlap_mentioned_p (src, PATTERN (q))
- || reg_set_p (src, q)))
+ else if (src != inc_dest
+ && (reg_overlap_mentioned_p (src, PATTERN (q))
+ || reg_set_p (src, q)))
break;
- if (reg_set_p (inc_dest, q))
+ else if (reg_set_p (inc_dest, q))
break;
- if (reg_overlap_mentioned_p (inc_dest, PATTERN (q)))
+ else if (reg_overlap_mentioned_p (inc_dest, PATTERN (q)))
{
try_auto_increment (q, post_inc,
post_inc_set, inc_dest, newconst, 1);
}
}
}
+
/* Move the death note for DST to INSN if it is used
there. */
if (reg_overlap_mentioned_p (dst, PATTERN (insn)))
return ! rtx_unstable_p (x);
}
}
+\f
+/* Track stack adjustments and stack memory references. Attempt to
+ reduce the number of stack adjustments by back-propogating across
+ the memory references.
+
+ This is intended primarily for use with targets that do not define
+ ACCUMULATE_OUTGOING_ARGS. It is of significantly more value to
+ targets that define PREFERRED_STACK_BOUNDARY more aligned than
+ STACK_BOUNDARY (e.g. x86), or if not all registers can be pushed
+ (e.g. x86 fp regs) which would ordinarily have to be implemented
+ as a sub/mov pair due to restrictions in calls.c.
+
+ Propogation stops when any of the insns that need adjusting are
+ (a) no longer valid because we've exceeded their range, (b) a
+ non-trivial push instruction, or (c) a call instruction.
+
+ Restriction B is based on the assumption that push instructions
+ are smaller or faster. If a port really wants to remove all
+ pushes, it should have defined ACCUMULATE_OUTGOING_ARGS. The
+ one exception that is made is for an add immediately followed
+ by a push. */
+
+/* This structure records stack memory references between stack adjusting
+ instructions. */
+
+struct csa_memlist
+{
+ HOST_WIDE_INT sp_offset;
+ rtx insn, *mem;
+ struct csa_memlist *next;
+};
+
+static int stack_memref_p PARAMS ((rtx));
+static rtx single_set_for_csa PARAMS ((rtx));
+static void free_csa_memlist PARAMS ((struct csa_memlist *));
+static struct csa_memlist *record_one_stack_memref
+ PARAMS ((rtx, rtx *, struct csa_memlist *));
+static int try_apply_stack_adjustment
+ PARAMS ((rtx, struct csa_memlist *, HOST_WIDE_INT, HOST_WIDE_INT));
+static void combine_stack_adjustments_for_block PARAMS ((basic_block));
+static int record_stack_memrefs PARAMS ((rtx *, void *));
+
+
+/* Main entry point for stack adjustment combination. */
+
+void
+combine_stack_adjustments ()
+{
+ int i;
+
+ for (i = 0; i < n_basic_blocks; ++i)
+ combine_stack_adjustments_for_block (BASIC_BLOCK (i));
+}
+
+/* Recognize a MEM of the form (sp) or (plus sp const). */
+
+static int
+stack_memref_p (x)
+ rtx x;
+{
+ if (GET_CODE (x) != MEM)
+ return 0;
+ x = XEXP (x, 0);
+
+ if (x == stack_pointer_rtx)
+ return 1;
+ if (GET_CODE (x) == PLUS
+ && XEXP (x, 0) == stack_pointer_rtx
+ && GET_CODE (XEXP (x, 1)) == CONST_INT)
+ return 1;
+
+ return 0;
+}
+
+/* Recognize either normal single_set or the hack in i386.md for
+ tying fp and sp adjustments. */
+
+static rtx
+single_set_for_csa (insn)
+ rtx insn;
+{
+ int i;
+ rtx tmp = single_set (insn);
+ if (tmp)
+ return tmp;
+
+ if (GET_CODE (insn) != INSN
+ || GET_CODE (PATTERN (insn)) != PARALLEL)
+ return NULL_RTX;
+
+ tmp = PATTERN (insn);
+ if (GET_CODE (XVECEXP (tmp, 0, 0)) != SET)
+ return NULL_RTX;
+
+ for (i = 1; i < XVECLEN (tmp, 0); ++i)
+ {
+ rtx this = XVECEXP (tmp, 0, i);
+
+ /* The special case is allowing a no-op set. */
+ if (GET_CODE (this) == SET
+ && SET_SRC (this) == SET_DEST (this))
+ ;
+ else if (GET_CODE (this) != CLOBBER
+ && GET_CODE (this) != USE)
+ return NULL_RTX;
+ }
+
+ return XVECEXP (tmp, 0, 0);
+}
+
+/* Free the list of csa_memlist nodes. */
+
+static void
+free_csa_memlist (memlist)
+ struct csa_memlist *memlist;
+{
+ struct csa_memlist *next;
+ for (; memlist ; memlist = next)
+ {
+ next = memlist->next;
+ free (memlist);
+ }
+}
+
+/* Create a new csa_memlist node from the given memory reference.
+ It is already known that the memory is stack_memref_p. */
+
+static struct csa_memlist *
+record_one_stack_memref (insn, mem, next_memlist)
+ rtx insn, *mem;
+ struct csa_memlist *next_memlist;
+{
+ struct csa_memlist *ml;
+
+ ml = (struct csa_memlist *) xmalloc (sizeof (*ml));
+
+ if (XEXP (*mem, 0) == stack_pointer_rtx)
+ ml->sp_offset = 0;
+ else
+ ml->sp_offset = INTVAL (XEXP (XEXP (*mem, 0), 1));
+
+ ml->insn = insn;
+ ml->mem = mem;
+ ml->next = next_memlist;
+
+ return ml;
+}
+
+/* Attempt to apply ADJUST to the stack adjusting insn INSN, as well
+ as each of the memories in MEMLIST. Return true on success. */
+
+static int
+try_apply_stack_adjustment (insn, memlist, new_adjust, delta)
+ rtx insn;
+ struct csa_memlist *memlist;
+ HOST_WIDE_INT new_adjust, delta;
+{
+ struct csa_memlist *ml;
+ rtx set;
+
+ /* We know INSN matches single_set_for_csa, because that's what we
+ recognized earlier. However, if INSN is not single_set, it is
+ doing double duty as a barrier for frame pointer memory accesses,
+ which we are not recording. Therefore, an adjust insn that is not
+ single_set may not have a positive delta applied. */
+
+ if (delta > 0 && ! single_set (insn))
+ return 0;
+ set = single_set_for_csa (insn);
+ validate_change (insn, &XEXP (SET_SRC (set), 1), GEN_INT (new_adjust), 1);
+
+ for (ml = memlist; ml ; ml = ml->next)
+ {
+ HOST_WIDE_INT c = ml->sp_offset - delta;
+ rtx new = gen_rtx_MEM (GET_MODE (*ml->mem),
+ plus_constant (stack_pointer_rtx, c));
+
+ /* Don't reference memory below the stack pointer. */
+ if (c < 0)
+ {
+ cancel_changes (0);
+ return 0;
+ }
+
+ MEM_COPY_ATTRIBUTES (new, *ml->mem);
+ validate_change (ml->insn, ml->mem, new, 1);
+ }
+
+ if (apply_change_group ())
+ {
+ /* Succeeded. Update our knowledge of the memory references. */
+ for (ml = memlist; ml ; ml = ml->next)
+ ml->sp_offset -= delta;
+
+ return 1;
+ }
+ else
+ return 0;
+}
+
+/* Called via for_each_rtx and used to record all stack memory references in
+ the insn and discard all other stack pointer references. */
+struct record_stack_memrefs_data
+{
+ rtx insn;
+ struct csa_memlist *memlist;
+};
+
+static int
+record_stack_memrefs (xp, data)
+ rtx *xp;
+ void *data;
+{
+ rtx x = *xp;
+ struct record_stack_memrefs_data *d =
+ (struct record_stack_memrefs_data *) data;
+ if (!x)
+ return 0;
+ switch (GET_CODE (x))
+ {
+ case MEM:
+ if (!reg_mentioned_p (stack_pointer_rtx, x))
+ return -1;
+ /* We are not able to handle correctly all possible memrefs containing
+ stack pointer, so this check is neccesary. */
+ if (stack_memref_p (x))
+ {
+ d->memlist = record_one_stack_memref (d->insn, xp, d->memlist);
+ return -1;
+ }
+ return 1;
+ case REG:
+ /* ??? We want be able to handle non-memory stack pointer references
+ later. For now just discard all insns refering to stack pointer
+ outside mem expressions. We would probably want to teach
+ validate_replace to simplify expressions first. */
+ if (x == stack_pointer_rtx)
+ return 1;
+ break;
+ default:
+ break;
+ }
+ return 0;
+}
+
+/* Subroutine of combine_stack_adjustments, called for each basic block. */
+
+static void
+combine_stack_adjustments_for_block (bb)
+ basic_block bb;
+{
+ HOST_WIDE_INT last_sp_adjust = 0;
+ rtx last_sp_set = NULL_RTX;
+ struct csa_memlist *memlist = NULL;
+ rtx pending_delete;
+ rtx insn, next;
+ struct record_stack_memrefs_data data;
+
+ for (insn = bb->head; ; insn = next)
+ {
+ rtx set;
+
+ pending_delete = NULL_RTX;
+ next = NEXT_INSN (insn);
+
+ if (! INSN_P (insn))
+ goto processed;
+
+ set = single_set_for_csa (insn);
+ if (set)
+ {
+ rtx dest = SET_DEST (set);
+ rtx src = SET_SRC (set);
+
+ /* Find constant additions to the stack pointer. */
+ if (dest == stack_pointer_rtx
+ && GET_CODE (src) == PLUS
+ && XEXP (src, 0) == stack_pointer_rtx
+ && GET_CODE (XEXP (src, 1)) == CONST_INT)
+ {
+ HOST_WIDE_INT this_adjust = INTVAL (XEXP (src, 1));
+
+ /* If we've not seen an adjustment previously, record
+ it now and continue. */
+ if (! last_sp_set)
+ {
+ last_sp_set = insn;
+ last_sp_adjust = this_adjust;
+ goto processed;
+ }
+
+ /* If not all recorded memrefs can be adjusted, or the
+ adjustment is now too large for a constant addition,
+ we cannot merge the two stack adjustments. */
+ if (! try_apply_stack_adjustment (last_sp_set, memlist,
+ last_sp_adjust + this_adjust,
+ this_adjust))
+ {
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = insn;
+ last_sp_adjust = this_adjust;
+ goto processed;
+ }
+
+ /* It worked! */
+ pending_delete = insn;
+ last_sp_adjust += this_adjust;
+
+ /* If, by some accident, the adjustments cancel out,
+ delete both insns and start from scratch. */
+ if (last_sp_adjust == 0)
+ {
+ if (last_sp_set == bb->head)
+ bb->head = NEXT_INSN (last_sp_set);
+ flow_delete_insn (last_sp_set);
+
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ }
+
+ goto processed;
+ }
+
+ /* Find a predecrement of exactly the previous adjustment and
+ turn it into a direct store. Obviously we can't do this if
+ there were any intervening uses of the stack pointer. */
+ if (memlist == NULL
+ && GET_CODE (dest) == MEM
+ && ((GET_CODE (XEXP (dest, 0)) == PRE_DEC
+ && (last_sp_adjust
+ == (HOST_WIDE_INT) GET_MODE_SIZE (GET_MODE (dest))))
+ || (GET_CODE (XEXP (dest, 0)) == PRE_MODIFY
+ && GET_CODE (XEXP (XEXP (dest, 0), 1)) == PLUS
+ && XEXP (XEXP (XEXP (dest, 0), 1), 0) == stack_pointer_rtx
+ && (GET_CODE (XEXP (XEXP (XEXP (dest, 0), 1), 1))
+ == CONST_INT)
+ && (INTVAL (XEXP (XEXP (XEXP (dest, 0), 1), 1))
+ == -last_sp_adjust)))
+ && XEXP (XEXP (dest, 0), 0) == stack_pointer_rtx
+ && ! reg_mentioned_p (stack_pointer_rtx, src)
+ && memory_address_p (GET_MODE (dest), stack_pointer_rtx)
+ && validate_change (insn, &SET_DEST (set),
+ change_address (dest, VOIDmode,
+ stack_pointer_rtx), 0))
+ {
+ if (last_sp_set == bb->head)
+ bb->head = NEXT_INSN (last_sp_set);
+ flow_delete_insn (last_sp_set);
+
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ last_sp_adjust = 0;
+ goto processed;
+ }
+ }
+
+ data.insn = insn;
+ data.memlist = memlist;
+ if (GET_CODE (insn) != CALL_INSN && last_sp_set
+ && !for_each_rtx (&PATTERN (insn), record_stack_memrefs, &data))
+ {
+ memlist = data.memlist;
+ goto processed;
+ }
+ memlist = data.memlist;
+
+ /* Otherwise, we were not able to process the instruction.
+ Do not continue collecting data across such a one. */
+ if (last_sp_set
+ && (GET_CODE (insn) == CALL_INSN
+ || reg_mentioned_p (stack_pointer_rtx, PATTERN (insn))))
+ {
+ free_csa_memlist (memlist);
+ memlist = NULL;
+ last_sp_set = NULL_RTX;
+ last_sp_adjust = 0;
+ }
+
+ processed:
+ if (insn == bb->end)
+ break;
+
+ if (pending_delete)
+ flow_delete_insn (pending_delete);
+ }
+
+ if (pending_delete)
+ {
+ bb->end = PREV_INSN (pending_delete);
+ flow_delete_insn (pending_delete);
+ }
+}
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