diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 658215ac154e769f3322e83bd33d01224327db18..efdf7746069ea3332a235146b35c56ee92f1b132 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+Wed Apr 19 12:02:37 MET DST 2000 Jan Hubicka <jh@suse.cz>
+
+ * loop.c (check_insn_for_bivs, for_every_insn_in_loop,
+ check_insn_for_givs): Break out from ...
+ (strength_reduce) ... here; use for_every_insn_in_loop to call
+ check_insn_for_givs.
+ * loop.h (for_every_insn_in_loop): Declare.
+ (loop_insn_callback): New type.
+
2000-04-18 Zack Weinberg <zack@wolery.cumb.org>
* cpplib.c (do_pragma_poison): Strings in the token buffer are
diff --git a/gcc/loop.c b/gcc/loop.c
index 8a3eb4df741bb500412e59db85e1a7ffd78f0175..ac19372ee2a0d3140457e06b3621b42704bf3633 100644
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -308,6 +308,8 @@ static int replace_loop_reg PARAMS ((rtx *, void *));
static void note_reg_stored PARAMS ((rtx, rtx, void *));
static void try_copy_prop PARAMS ((const struct loop *, rtx, unsigned int));
static int replace_label PARAMS ((rtx *, void *));
+static void check_insn_for_givs PARAMS((struct loop *, rtx, int, int));
+static void check_insn_for_bivs PARAMS((struct loop *, rtx, int, int));
typedef struct rtx_and_int {
rtx r;
@@ -3694,127 +3696,47 @@ static rtx addr_placeholder;
was rerun in loop_optimize whenever a register was added or moved.
Also, some of the optimizations could be a little less conservative. */
-/* Perform strength reduction and induction variable elimination.
-
- Pseudo registers created during this function will be beyond the last
- valid index in several tables including n_times_set and regno_last_uid.
- This does not cause a problem here, because the added registers cannot be
- givs outside of their loop, and hence will never be reconsidered.
- But scan_loop must check regnos to make sure they are in bounds. */
-
-static void
-strength_reduce (loop, insn_count, unroll_p, bct_p)
+/* Scan the loop body and call FNCALL for each insn. In the addition to the
+ LOOP and INSN parameters pass MAYBE_MULTIPLE and NOT_EVERY_ITERATION to the
+ callback.
+
+ NOT_EVERY_ITERATION if current insn is not executed at least once for every
+ loop iteration except for the last one.
+
+ MAYBE_MULTIPLE is 1 if current insn may be executed more than once for every
+ loop iteration.
+ */
+void
+for_each_insn_in_loop (loop, fncall)
struct loop *loop;
- int insn_count;
- int unroll_p, bct_p ATTRIBUTE_UNUSED;
+ loop_insn_callback fncall;
{
- rtx p;
- rtx set;
- rtx inc_val;
- rtx mult_val;
- rtx dest_reg;
- rtx *location;
/* This is 1 if current insn is not executed at least once for every loop
iteration. */
int not_every_iteration = 0;
- /* This is 1 if current insn may be executed more than once for every
- loop iteration. */
int maybe_multiple = 0;
- /* This is 1 if we have past a branch back to the top of the loop
- (aka a loop latch). */
int past_loop_latch = 0;
- /* Temporary list pointers for traversing loop_iv_list. */
- struct iv_class *bl, **backbl;
- struct loop_info *loop_info = LOOP_INFO (loop);
- /* Ratio of extra register life span we can justify
- for saving an instruction. More if loop doesn't call subroutines
- since in that case saving an insn makes more difference
- and more registers are available. */
- /* ??? could set this to last value of threshold in move_movables */
- int threshold = (loop_info->has_call ? 1 : 2) * (3 + n_non_fixed_regs);
- /* Map of pseudo-register replacements. */
- rtx *reg_map = NULL;
- int reg_map_size;
- int call_seen;
- rtx test;
- rtx end_insert_before;
int loop_depth = 0;
- int n_extra_increment;
- int unrolled_insn_copies = 0;
- rtx loop_start = loop->start;
- rtx loop_end = loop->end;
- rtx loop_scan_start = loop->scan_start;
- rtx loop_top = loop->top;
- rtx loop_cont = loop->cont;
+ rtx p;
/* If loop_scan_start points to the loop exit test, we have to be wary of
subversive use of gotos inside expression statements. */
- if (prev_nonnote_insn (loop_scan_start) != prev_nonnote_insn (loop_start))
- maybe_multiple = back_branch_in_range_p (loop, loop_scan_start);
-
- VARRAY_INT_INIT (reg_iv_type, max_reg_before_loop, "reg_iv_type");
- VARRAY_GENERIC_PTR_INIT (reg_iv_info, max_reg_before_loop, "reg_iv_info");
- reg_biv_class = (struct iv_class **)
- xcalloc (max_reg_before_loop, sizeof (struct iv_class *));
-
- loop_iv_list = 0;
- addr_placeholder = gen_reg_rtx (Pmode);
-
- /* Save insn immediately after the loop_end. Insns inserted after loop_end
- must be put before this insn, so that they will appear in the right
- order (i.e. loop order).
-
- If loop_end is the end of the current function, then emit a
- NOTE_INSN_DELETED after loop_end and set end_insert_before to the
- dummy note insn. */
- if (NEXT_INSN (loop_end) != 0)
- end_insert_before = NEXT_INSN (loop_end);
- else
- end_insert_before = emit_note_after (NOTE_INSN_DELETED, loop_end);
+ if (prev_nonnote_insn (loop->scan_start) != prev_nonnote_insn (loop->start))
+ maybe_multiple = back_branch_in_range_p (loop, loop->scan_start);
/* Scan through loop to find all possible bivs. */
- for (p = next_insn_in_loop (loop, loop_scan_start);
+ for (p = next_insn_in_loop (loop, loop->scan_start);
p != NULL_RTX;
p = next_insn_in_loop (loop, p))
{
- if (GET_CODE (p) == INSN
- && (set = single_set (p))
- && GET_CODE (SET_DEST (set)) == REG)
- {
- dest_reg = SET_DEST (set);
- if (REGNO (dest_reg) < max_reg_before_loop
- && REGNO (dest_reg) >= FIRST_PSEUDO_REGISTER
- && REG_IV_TYPE (REGNO (dest_reg)) != NOT_BASIC_INDUCT)
- {
- int multi_insn_incr = 0;
-
- if (basic_induction_var (loop, SET_SRC (set),
- GET_MODE (SET_SRC (set)),
- dest_reg, p, &inc_val, &mult_val,
- &location, &multi_insn_incr))
- {
- /* It is a possible basic induction variable.
- Create and initialize an induction structure for it. */
-
- struct induction *v
- = (struct induction *) alloca (sizeof (struct induction));
-
- record_biv (v, p, dest_reg, inc_val, mult_val, location,
- not_every_iteration, maybe_multiple,
- multi_insn_incr);
- REG_IV_TYPE (REGNO (dest_reg)) = BASIC_INDUCT;
- }
- else if (REGNO (dest_reg) < max_reg_before_loop)
- REG_IV_TYPE (REGNO (dest_reg)) = NOT_BASIC_INDUCT;
- }
- }
+ fncall (loop, p, maybe_multiple, not_every_iteration);
/* Past CODE_LABEL, we get to insns that may be executed multiple
- times. The only way we can be sure that they can't is if every
- jump insn between here and the end of the loop either
- returns, exits the loop, is a jump to a location that is still
- behind the label, or is a jump to the loop start. */
+ times. The only way we can be sure that they can't is if every
+ jump insn between here and the end of the loop either
+ returns, exits the loop, is a jump to a location that is still
+ behind the label, or is a jump to the loop start. */
if (GET_CODE (p) == CODE_LABEL)
{
@@ -3825,24 +3747,24 @@ strength_reduce (loop, insn_count, unroll_p, bct_p)
while (1)
{
insn = NEXT_INSN (insn);
- if (insn == loop_scan_start)
+ if (insn == loop->scan_start)
break;
- if (insn == loop_end)
+ if (insn == loop->end)
{
- if (loop_top != 0)
- insn = loop_top;
+ if (loop->top != 0)
+ insn = loop->top;
else
break;
- if (insn == loop_scan_start)
+ if (insn == loop->scan_start)
break;
}
if (GET_CODE (insn) == JUMP_INSN
&& GET_CODE (PATTERN (insn)) != RETURN
- && (! condjump_p (insn)
+ && (!condjump_p (insn)
|| (JUMP_LABEL (insn) != 0
- && JUMP_LABEL (insn) != loop_scan_start
- && ! loop_insn_first_p (p, JUMP_LABEL (insn)))))
+ && JUMP_LABEL (insn) != loop->scan_start
+ && !loop_insn_first_p (p, JUMP_LABEL (insn)))))
{
maybe_multiple = 1;
break;
@@ -3851,29 +3773,29 @@ strength_reduce (loop, insn_count, unroll_p, bct_p)
}
/* Past a jump, we get to insns for which we can't count
- on whether they will be executed during each iteration. */
+ on whether they will be executed during each iteration. */
/* This code appears twice in strength_reduce. There is also similar
- code in scan_loop. */
+ code in scan_loop. */
if (GET_CODE (p) == JUMP_INSN
- /* If we enter the loop in the middle, and scan around to the
- beginning, don't set not_every_iteration for that.
- This can be any kind of jump, since we want to know if insns
- will be executed if the loop is executed. */
- && ! (JUMP_LABEL (p) == loop_top
- && ((NEXT_INSN (NEXT_INSN (p)) == loop_end && simplejump_p (p))
- || (NEXT_INSN (p) == loop_end && condjump_p (p)))))
+ /* If we enter the loop in the middle, and scan around to the
+ beginning, don't set not_every_iteration for that.
+ This can be any kind of jump, since we want to know if insns
+ will be executed if the loop is executed. */
+ && !(JUMP_LABEL (p) == loop->top
+ && ((NEXT_INSN (NEXT_INSN (p)) == loop->end && simplejump_p (p))
+ || (NEXT_INSN (p) == loop->end && condjump_p (p)))))
{
rtx label = 0;
/* If this is a jump outside the loop, then it also doesn't
matter. Check to see if the target of this branch is on the
loop->exits_labels list. */
-
+
for (label = loop->exit_labels; label; label = LABEL_NEXTREF (label))
if (XEXP (label, 0) == JUMP_LABEL (p))
break;
- if (! label)
+ if (!label)
not_every_iteration = 1;
}
@@ -3896,34 +3818,93 @@ strength_reduce (loop, insn_count, unroll_p, bct_p)
}
/* Note if we pass a loop latch. If we do, then we can not clear
- NOT_EVERY_ITERATION below when we pass the last CODE_LABEL in
- a loop since a jump before the last CODE_LABEL may have started
- a new loop iteration.
-
- Note that LOOP_TOP is only set for rotated loops and we need
- this check for all loops, so compare against the CODE_LABEL
- which immediately follows LOOP_START. */
- if (GET_CODE (p) == JUMP_INSN
- && JUMP_LABEL (p) == NEXT_INSN (loop_start))
+ NOT_EVERY_ITERATION below when we pass the last CODE_LABEL in
+ a loop since a jump before the last CODE_LABEL may have started
+ a new loop iteration.
+
+ Note that LOOP_TOP is only set for rotated loops and we need
+ this check for all loops, so compare against the CODE_LABEL
+ which immediately follows LOOP_START. */
+ if (GET_CODE (p) == JUMP_INSN
+ && JUMP_LABEL (p) == NEXT_INSN (loop->start))
past_loop_latch = 1;
/* Unlike in the code motion pass where MAYBE_NEVER indicates that
- an insn may never be executed, NOT_EVERY_ITERATION indicates whether
- or not an insn is known to be executed each iteration of the
- loop, whether or not any iterations are known to occur.
+ an insn may never be executed, NOT_EVERY_ITERATION indicates whether
+ or not an insn is known to be executed each iteration of the
+ loop, whether or not any iterations are known to occur.
- Therefore, if we have just passed a label and have no more labels
- between here and the test insn of the loop, and we have not passed
- a jump to the top of the loop, then we know these insns will be
- executed each iteration. */
+ Therefore, if we have just passed a label and have no more labels
+ between here and the test insn of the loop, and we have not passed
+ a jump to the top of the loop, then we know these insns will be
+ executed each iteration. */
- if (not_every_iteration
- && ! past_loop_latch
+ if (not_every_iteration
+ && !past_loop_latch
&& GET_CODE (p) == CODE_LABEL
- && no_labels_between_p (p, loop_end)
- && loop_insn_first_p (p, loop_cont))
+ && no_labels_between_p (p, loop->end)
+ && loop_insn_first_p (p, loop->cont))
not_every_iteration = 0;
}
+}
+
+/* Perform strength reduction and induction variable elimination.
+
+ Pseudo registers created during this function will be beyond the last
+ valid index in several tables including n_times_set and regno_last_uid.
+ This does not cause a problem here, because the added registers cannot be
+ givs outside of their loop, and hence will never be reconsidered.
+ But scan_loop must check regnos to make sure they are in bounds. */
+
+static void
+strength_reduce (loop, insn_count, unroll_p, bct_p)
+ struct loop *loop;
+ int insn_count;
+ int unroll_p, bct_p ATTRIBUTE_UNUSED;
+{
+ rtx p;
+ /* Temporary list pointers for traversing loop_iv_list. */
+ struct iv_class *bl, **backbl;
+ struct loop_info *loop_info = LOOP_INFO (loop);
+ /* Ratio of extra register life span we can justify
+ for saving an instruction. More if loop doesn't call subroutines
+ since in that case saving an insn makes more difference
+ and more registers are available. */
+ /* ??? could set this to last value of threshold in move_movables */
+ int threshold = (loop_info->has_call ? 1 : 2) * (3 + n_non_fixed_regs);
+ /* Map of pseudo-register replacements. */
+ rtx *reg_map = NULL;
+ int reg_map_size;
+ int call_seen;
+ rtx test;
+ rtx end_insert_before;
+ int n_extra_increment;
+ int unrolled_insn_copies = 0;
+ rtx loop_start = loop->start;
+ rtx loop_end = loop->end;
+ rtx loop_scan_start = loop->scan_start;
+
+ VARRAY_INT_INIT (reg_iv_type, max_reg_before_loop, "reg_iv_type");
+ VARRAY_GENERIC_PTR_INIT (reg_iv_info, max_reg_before_loop, "reg_iv_info");
+ reg_biv_class = (struct iv_class **)
+ xcalloc (max_reg_before_loop, sizeof (struct iv_class *));
+
+ loop_iv_list = 0;
+ addr_placeholder = gen_reg_rtx (Pmode);
+
+ /* Save insn immediately after the loop_end. Insns inserted after loop_end
+ must be put before this insn, so that they will appear in the right
+ order (i.e. loop order).
+
+ If loop_end is the end of the current function, then emit a
+ NOTE_INSN_DELETED after loop_end and set end_insert_before to the
+ dummy note insn. */
+ if (NEXT_INSN (loop_end) != 0)
+ end_insert_before = NEXT_INSN (loop_end);
+ else
+ end_insert_before = emit_note_after (NOTE_INSN_DELETED, loop_end);
+
+ for_each_insn_in_loop (loop, check_insn_for_bivs);
/* Scan loop_iv_list to remove all regs that proved not to be bivs.
Make a sanity check against n_times_set. */
@@ -4430,203 +4411,7 @@ strength_reduce (loop, insn_count, unroll_p, bct_p)
/* Search the loop for general induction variables. */
- /* A register is a giv if: it is only set once, it is a function of a
- biv and a constant (or invariant), and it is not a biv. */
-
- not_every_iteration = 0;
- loop_depth = 0;
- maybe_multiple = 0;
- p = loop_scan_start;
- while (1)
- {
- p = NEXT_INSN (p);
- /* At end of a straight-in loop, we are done.
- At end of a loop entered at the bottom, scan the top. */
- if (p == loop_scan_start)
- break;
- if (p == loop_end)
- {
- if (loop_top != 0)
- p = loop_top;
- else
- break;
- if (p == loop_scan_start)
- break;
- }
-
- /* Look for a general induction variable in a register. */
- if (GET_CODE (p) == INSN
- && (set = single_set (p))
- && GET_CODE (SET_DEST (set)) == REG
- && ! VARRAY_CHAR (may_not_optimize, REGNO (SET_DEST (set))))
- {
- rtx src_reg;
- rtx add_val;
- rtx mult_val;
- int benefit;
- rtx regnote = 0;
- rtx last_consec_insn;
-
- dest_reg = SET_DEST (set);
- if (REGNO (dest_reg) < FIRST_PSEUDO_REGISTER)
- continue;
-
- if (/* SET_SRC is a giv. */
- (general_induction_var (loop, SET_SRC (set), &src_reg, &add_val,
- &mult_val, 0, &benefit)
- /* Equivalent expression is a giv. */
- || ((regnote = find_reg_note (p, REG_EQUAL, NULL_RTX))
- && general_induction_var (loop, XEXP (regnote, 0), &src_reg,
- &add_val, &mult_val, 0,
- &benefit)))
- /* Don't try to handle any regs made by loop optimization.
- We have nothing on them in regno_first_uid, etc. */
- && REGNO (dest_reg) < max_reg_before_loop
- /* Don't recognize a BASIC_INDUCT_VAR here. */
- && dest_reg != src_reg
- /* This must be the only place where the register is set. */
- && (VARRAY_INT (n_times_set, REGNO (dest_reg)) == 1
- /* or all sets must be consecutive and make a giv. */
- || (benefit = consec_sets_giv (loop, benefit, p,
- src_reg, dest_reg,
- &add_val, &mult_val,
- &last_consec_insn))))
- {
- struct induction *v
- = (struct induction *) alloca (sizeof (struct induction));
-
- /* If this is a library call, increase benefit. */
- if (find_reg_note (p, REG_RETVAL, NULL_RTX))
- benefit += libcall_benefit (p);
-
- /* Skip the consecutive insns, if there are any. */
- if (VARRAY_INT (n_times_set, REGNO (dest_reg)) != 1)
- p = last_consec_insn;
-
- record_giv (loop, v, p, src_reg, dest_reg, mult_val, add_val,
- benefit, DEST_REG, not_every_iteration,
- maybe_multiple, NULL_PTR);
-
- }
- }
-
-#ifndef DONT_REDUCE_ADDR
- /* Look for givs which are memory addresses. */
- /* This resulted in worse code on a VAX 8600. I wonder if it
- still does. */
- if (GET_CODE (p) == INSN)
- find_mem_givs (loop, PATTERN (p), p, not_every_iteration,
- maybe_multiple);
-#endif
-
- /* Update the status of whether giv can derive other givs. This can
- change when we pass a label or an insn that updates a biv. */
- if (GET_CODE (p) == INSN || GET_CODE (p) == JUMP_INSN
- || GET_CODE (p) == CODE_LABEL)
- update_giv_derive (loop, p);
-
- /* Past CODE_LABEL, we get to insns that may be executed multiple
- times. The only way we can be sure that they can't is if every
- every jump insn between here and the end of the loop either
- returns, exits the loop, is a forward jump, or is a jump
- to the loop start. */
-
- if (GET_CODE (p) == CODE_LABEL)
- {
- rtx insn = p;
-
- maybe_multiple = 0;
-
- while (1)
- {
- insn = NEXT_INSN (insn);
- if (insn == loop_scan_start)
- break;
- if (insn == loop_end)
- {
- if (loop_top != 0)
- insn = loop_top;
- else
- break;
- if (insn == loop_scan_start)
- break;
- }
-
- if (GET_CODE (insn) == JUMP_INSN
- && GET_CODE (PATTERN (insn)) != RETURN
- && (! condjump_p (insn)
- || (JUMP_LABEL (insn) != 0
- && JUMP_LABEL (insn) != loop_scan_start
- && (INSN_UID (JUMP_LABEL (insn)) >= max_uid_for_loop
- || INSN_UID (insn) >= max_uid_for_loop
- || (INSN_LUID (JUMP_LABEL (insn))
- < INSN_LUID (insn))))))
- {
- maybe_multiple = 1;
- break;
- }
- }
- }
-
- /* Past a jump, we get to insns for which we can't count
- on whether they will be executed during each iteration. */
- /* This code appears twice in strength_reduce. There is also similar
- code in scan_loop. */
- if (GET_CODE (p) == JUMP_INSN
- /* If we enter the loop in the middle, and scan around to the
- beginning, don't set not_every_iteration for that.
- This can be any kind of jump, since we want to know if insns
- will be executed if the loop is executed. */
- && ! (JUMP_LABEL (p) == loop_top
- && ((NEXT_INSN (NEXT_INSN (p)) == loop_end && simplejump_p (p))
- || (NEXT_INSN (p) == loop_end && condjump_p (p)))))
- {
- rtx label = 0;
-
- /* If this is a jump outside the loop, then it also doesn't
- matter. Check to see if the target of this branch is on the
- loop->exits_labels list. */
-
- for (label = loop->exit_labels; label; label = LABEL_NEXTREF (label))
- if (XEXP (label, 0) == JUMP_LABEL (p))
- break;
-
- if (! label)
- not_every_iteration = 1;
- }
-
- else if (GET_CODE (p) == NOTE)
- {
- /* At the virtual top of a converted loop, insns are again known to
- be executed each iteration: logically, the loop begins here
- even though the exit code has been duplicated.
-
- Insns are also again known to be executed each iteration at
- the LOOP_CONT note. */
- if ((NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_VTOP
- || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_CONT)
- && loop_depth == 0)
- not_every_iteration = 0;
- else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG)
- loop_depth++;
- else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END)
- loop_depth--;
- }
-
- /* Unlike in the code motion pass where MAYBE_NEVER indicates that
- an insn may never be executed, NOT_EVERY_ITERATION indicates whether
- or not an insn is known to be executed each iteration of the
- loop, whether or not any iterations are known to occur.
-
- Therefore, if we have just passed a label and have no more labels
- between here and the test insn of the loop, we know these insns
- will be executed each iteration. */
-
- if (not_every_iteration && GET_CODE (p) == CODE_LABEL
- && no_labels_between_p (p, loop_end)
- && loop_insn_first_p (p, loop_cont))
- not_every_iteration = 0;
- }
+ for_each_insn_in_loop (loop, check_insn_for_givs);
/* Try to calculate and save the number of loop iterations. This is
set to zero if the actual number can not be calculated. This must
@@ -5282,6 +5067,138 @@ egress:
free (reg_map);
}
+/*Record all basic induction variables calculated in the insn. */
+static void
+check_insn_for_bivs (loop, p, not_every_iteration, maybe_multiple)
+ struct loop *loop;
+ rtx p;
+ int not_every_iteration;
+ int maybe_multiple;
+{
+ rtx set;
+ rtx dest_reg;
+ rtx inc_val;
+ rtx mult_val;
+ rtx *location;
+
+ if (GET_CODE (p) == INSN
+ && (set = single_set (p))
+ && GET_CODE (SET_DEST (set)) == REG)
+ {
+ dest_reg = SET_DEST (set);
+ if (REGNO (dest_reg) < max_reg_before_loop
+ && REGNO (dest_reg) >= FIRST_PSEUDO_REGISTER
+ && REG_IV_TYPE (REGNO (dest_reg)) != NOT_BASIC_INDUCT)
+ {
+ int multi_insn_incr = 0;
+
+ if (basic_induction_var (loop, SET_SRC (set),
+ GET_MODE (SET_SRC (set)),
+ dest_reg, p, &inc_val, &mult_val,
+ &location, &multi_insn_incr))
+ {
+ /* It is a possible basic induction variable.
+ Create and initialize an induction structure for it. */
+
+ struct induction *v
+ = (struct induction *) oballoc (sizeof (struct induction));
+
+ record_biv (v, p, dest_reg, inc_val, mult_val, location,
+ not_every_iteration, maybe_multiple,
+ multi_insn_incr);
+ REG_IV_TYPE (REGNO (dest_reg)) = BASIC_INDUCT;
+ }
+ else if (REGNO (dest_reg) < max_reg_before_loop)
+ REG_IV_TYPE (REGNO (dest_reg)) = NOT_BASIC_INDUCT;
+ }
+ }
+}
+
+/* Record all givs calculated in the insn.
+ A register is a giv if: it is only set once, it is a function of a
+ biv and a constant (or invariant), and it is not a biv. */
+static void
+check_insn_for_givs (loop, p, not_every_iteration, maybe_multiple)
+ struct loop *loop;
+ rtx p;
+ int not_every_iteration;
+ int maybe_multiple;
+{
+ rtx set;
+ /* Look for a general induction variable in a register. */
+ if (GET_CODE (p) == INSN
+ && (set = single_set (p))
+ && GET_CODE (SET_DEST (set)) == REG
+ && ! VARRAY_CHAR (may_not_optimize, REGNO (SET_DEST (set))))
+ {
+ rtx src_reg;
+ rtx dest_reg;
+ rtx add_val;
+ rtx mult_val;
+ int benefit;
+ rtx regnote = 0;
+ rtx last_consec_insn;
+
+ dest_reg = SET_DEST (set);
+ if (REGNO (dest_reg) < FIRST_PSEUDO_REGISTER)
+ return;
+
+ if (/* SET_SRC is a giv. */
+ (general_induction_var (loop, SET_SRC (set), &src_reg, &add_val,
+ &mult_val, 0, &benefit)
+ /* Equivalent expression is a giv. */
+ || ((regnote = find_reg_note (p, REG_EQUAL, NULL_RTX))
+ && general_induction_var (loop, XEXP (regnote, 0), &src_reg,
+ &add_val, &mult_val, 0,
+ &benefit)))
+ /* Don't try to handle any regs made by loop optimization.
+ We have nothing on them in regno_first_uid, etc. */
+ && REGNO (dest_reg) < max_reg_before_loop
+ /* Don't recognize a BASIC_INDUCT_VAR here. */
+ && dest_reg != src_reg
+ /* This must be the only place where the register is set. */
+ && (VARRAY_INT (n_times_set, REGNO (dest_reg)) == 1
+ /* or all sets must be consecutive and make a giv. */
+ || (benefit = consec_sets_giv (loop, benefit, p,
+ src_reg, dest_reg,
+ &add_val, &mult_val,
+ &last_consec_insn))))
+ {
+ struct induction *v
+ = (struct induction *) oballoc (sizeof (struct induction));
+
+ /* If this is a library call, increase benefit. */
+ if (find_reg_note (p, REG_RETVAL, NULL_RTX))
+ benefit += libcall_benefit (p);
+
+ /* Skip the consecutive insns, if there are any. */
+ if (VARRAY_INT (n_times_set, REGNO (dest_reg)) != 1)
+ p = last_consec_insn;
+
+ record_giv (loop, v, p, src_reg, dest_reg, mult_val, add_val,
+ benefit, DEST_REG, not_every_iteration,
+ maybe_multiple, NULL_PTR);
+
+ }
+ }
+
+#ifndef DONT_REDUCE_ADDR
+ /* Look for givs which are memory addresses. */
+ /* This resulted in worse code on a VAX 8600. I wonder if it
+ still does. */
+ if (GET_CODE (p) == INSN)
+ find_mem_givs (loop, PATTERN (p), p, not_every_iteration,
+ maybe_multiple);
+#endif
+
+ /* Update the status of whether giv can derive other givs. This can
+ change when we pass a label or an insn that updates a biv. */
+ if (GET_CODE (p) == INSN || GET_CODE (p) == JUMP_INSN
+ || GET_CODE (p) == CODE_LABEL)
+ update_giv_derive (loop, p);
+
+}
+
/* Return 1 if X is a valid source for an initial value (or as value being
compared against in an initial test).
diff --git a/gcc/loop.h b/gcc/loop.h
index 703073372b6492ff51f52d077c694ed2c5de9ab6..390c1ce4b7c355a9aef74cd4a62b30d42b01d255 100644
--- a/gcc/loop.h
+++ b/gcc/loop.h
@@ -247,4 +247,6 @@ void emit_unrolled_add PARAMS ((rtx, rtx, rtx));
int back_branch_in_range_p PARAMS ((const struct loop *, rtx));
int loop_insn_first_p PARAMS ((rtx, rtx));
+typedef void (*loop_insn_callback ) PARAMS ((struct loop *, rtx, int, int));
+void for_each_insn_in_loop PARAMS ((struct loop *, loop_insn_callback));