/* If-conversion support.
- Copyright (C) 2000 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002 Free Software Foundation, Inc.
- This file is part of GNU CC.
+ This file is part of GCC.
- GNU CC is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
+ GCC is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
- GNU CC is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
+ GCC is distributed in the hope that it will be useful, but WITHOUT
+ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
+ License for more details.
You should have received a copy of the GNU General Public License
- along with GNU CC; see the file COPYING. If not, write to
- the Free Software Foundation, 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with GCC; see the file COPYING. If not, write to the Free
+ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+ 02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "flags.h"
#include "insn-config.h"
#include "recog.h"
+#include "except.h"
+#include "hard-reg-set.h"
#include "basic-block.h"
#include "expr.h"
+#include "real.h"
#include "output.h"
-#include "hard-reg-set.h"
+#include "toplev.h"
#include "tm_p.h"
#ifndef HAVE_decscc
#define HAVE_decscc 0
#endif
+#ifndef HAVE_trap
+#define HAVE_trap 0
+#endif
+#ifndef HAVE_conditional_trap
+#define HAVE_conditional_trap 0
+#endif
#ifndef MAX_CONDITIONAL_EXECUTE
#define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1)
#endif
-#define EDGE_COMPLEX (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_EH)
-
#define NULL_EDGE ((struct edge_def *)NULL)
#define NULL_BLOCK ((struct basic_block_def *)NULL)
/* # of basic blocks that were removed. */
static int num_removed_blocks;
+/* True if life data ok at present. */
+static bool life_data_ok;
+
/* The post-dominator relation on the original block numbers. */
static sbitmap *post_dominators;
static int count_bb_insns PARAMS ((basic_block));
static rtx first_active_insn PARAMS ((basic_block));
static int last_active_insn_p PARAMS ((basic_block, rtx));
+static int seq_contains_jump PARAMS ((rtx));
-static int cond_exec_process_insns PARAMS ((rtx, rtx, rtx, int));
+static int cond_exec_process_insns PARAMS ((rtx, rtx, rtx, rtx, int));
static rtx cond_exec_get_condition PARAMS ((rtx));
static int cond_exec_process_if_block PARAMS ((basic_block, basic_block,
basic_block, basic_block));
static rtx noce_get_condition PARAMS ((rtx, rtx *));
+static int noce_operand_ok PARAMS ((rtx));
static int noce_process_if_block PARAMS ((basic_block, basic_block,
basic_block, basic_block));
static int find_if_block PARAMS ((basic_block, edge, edge));
static int find_if_case_1 PARAMS ((basic_block, edge, edge));
static int find_if_case_2 PARAMS ((basic_block, edge, edge));
+static int find_cond_trap PARAMS ((basic_block, edge, edge));
+static rtx block_has_only_trap PARAMS ((basic_block));
static int find_memory PARAMS ((rtx *, void *));
static int dead_or_predicable PARAMS ((basic_block, basic_block,
- basic_block, rtx, int));
-\f
-/* Abuse the basic_block AUX field to store the original block index,
- as well as a flag indicating that the block should be rescaned for
- life analysis. */
-
-#define SET_ORIG_INDEX(BB,I) ((BB)->aux = (void *)((size_t)(I) << 1))
-#define ORIG_INDEX(BB) ((size_t)(BB)->aux >> 1)
-#define SET_UPDATE_LIFE(BB) ((BB)->aux = (void *)((size_t)(BB)->aux | 1))
-#define UPDATE_LIFE(BB) ((size_t)(BB)->aux & 1)
-
+ basic_block, basic_block, int));
+static void noce_emit_move_insn PARAMS ((rtx, rtx));
\f
/* Count the number of non-jump active insns in BB. */
return GET_CODE (insn) == JUMP_INSN;
}
+
+/* It is possible, especially when having dealt with multi-word
+ arithmetic, for the expanders to have emitted jumps. Search
+ through the sequence and return TRUE if a jump exists so that
+ we can abort the conversion. */
+
+static int
+seq_contains_jump (insn)
+ rtx insn;
+{
+ while (insn)
+ {
+ if (GET_CODE (insn) == JUMP_INSN)
+ return 1;
+ insn = NEXT_INSN (insn);
+ }
+ return 0;
+}
\f
/* Go through a bunch of insns, converting them to conditional
execution format if possible. Return TRUE if all of the non-note
insns were processed. */
static int
-cond_exec_process_insns (start, end, test, mod_ok)
+cond_exec_process_insns (start, end, test, prob_val, mod_ok)
rtx start; /* first insn to look at */
rtx end; /* last insn to look at */
rtx test; /* conditional execution test */
+ rtx prob_val; /* probability of branch taken. */
int mod_ok; /* true if modifications ok last insn. */
{
int must_be_last = FALSE;
rtx insn;
+ rtx pattern;
for (insn = start; ; insn = NEXT_INSN (insn))
{
if (GET_CODE (insn) != INSN && GET_CODE (insn) != CALL_INSN)
abort ();
+ /* Remove USE insns that get in the way. */
+ if (reload_completed && GET_CODE (PATTERN (insn)) == USE)
+ {
+ /* ??? Ug. Actually unlinking the thing is problematic,
+ given what we'd have to coordinate with our callers. */
+ PUT_CODE (insn, NOTE);
+ NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
+ NOTE_SOURCE_FILE (insn) = 0;
+ goto insn_done;
+ }
+
/* Last insn wasn't last? */
if (must_be_last)
return FALSE;
}
/* Now build the conditional form of the instruction. */
+ pattern = PATTERN (insn);
+
+ /* If the machine needs to modify the insn being conditionally executed,
+ say for example to force a constant integer operand into a temp
+ register, do so here. */
+#ifdef IFCVT_MODIFY_INSN
+ IFCVT_MODIFY_INSN (pattern, insn);
+ if (! pattern)
+ return FALSE;
+#endif
+
validate_change (insn, &PATTERN (insn),
gen_rtx_COND_EXEC (VOIDmode, copy_rtx (test),
- PATTERN (insn)), 1);
+ pattern), 1);
+
+ if (GET_CODE (insn) == CALL_INSN && prob_val)
+ validate_change (insn, ®_NOTES (insn),
+ alloc_EXPR_LIST (REG_BR_PROB, prob_val,
+ REG_NOTES (insn)), 1);
insn_done:
if (insn == end)
{
rtx test_if, cond;
- if (condjump_p (jump))
- test_if = SET_SRC (PATTERN (jump));
- else if (condjump_in_parallel_p (jump))
- test_if = SET_SRC (XVECEXP (PATTERN (jump), 0, 0));
+ if (any_condjump_p (jump))
+ test_if = SET_SRC (pc_set (jump));
else
return NULL_RTX;
cond = XEXP (test_if, 0);
reverse the condition. */
if (GET_CODE (XEXP (test_if, 2)) == LABEL_REF
&& XEXP (XEXP (test_if, 2), 0) == JUMP_LABEL (jump))
- cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
- GET_MODE (cond), XEXP (cond, 0),
- XEXP (cond, 1));
+ {
+ enum rtx_code rev = reversed_comparison_code (cond, jump);
+ if (rev == UNKNOWN)
+ return NULL_RTX;
+
+ cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
+ XEXP (cond, 1));
+ }
return cond;
}
rtx test_expr; /* expression in IF_THEN_ELSE that is tested */
rtx then_start; /* first insn in THEN block */
rtx then_end; /* last insn + 1 in THEN block */
- rtx else_start; /* first insn in ELSE block or NULL */
- rtx else_end; /* last insn + 1 in ELSE block */
- int max; /* max # of insns to convert. */
+ rtx else_start = NULL_RTX; /* first insn in ELSE block or NULL */
+ rtx else_end = NULL_RTX; /* last insn + 1 in ELSE block */
+ int max; /* max # of insns to convert. */
int then_mod_ok; /* whether conditional mods are ok in THEN */
rtx true_expr; /* test for else block insns */
rtx false_expr; /* test for then block insns */
+ rtx true_prob_val; /* probability of else block */
+ rtx false_prob_val; /* probability of then block */
int n_insns;
+ enum rtx_code false_code;
/* Find the conditional jump to the ELSE or JOIN part, and isolate
the test. */
if (! test_expr)
return FALSE;
+ /* If the conditional jump is more than just a conditional jump,
+ then we can not do conditional execution conversion on this block. */
+ if (!onlyjump_p (test_bb->end))
+ return FALSE;
+
/* Collect the bounds of where we're to search. */
then_start = then_bb->head;
then_end = then_bb->end;
+ /* Skip a label heading THEN block. */
+ if (GET_CODE (then_start) == CODE_LABEL)
+ then_start = NEXT_INSN (then_start);
+
/* Skip a (use (const_int 0)) or branch as the final insn. */
if (GET_CODE (then_end) == INSN
&& GET_CODE (PATTERN (then_end)) == USE
the conditionally executed code. */
true_expr = test_expr;
- false_expr = gen_rtx_fmt_ee (reverse_condition (GET_CODE (true_expr)),
- GET_MODE (true_expr), XEXP (true_expr, 0),
- XEXP (true_expr, 1));
+
+ false_code = reversed_comparison_code (true_expr, test_bb->end);
+ if (false_code != UNKNOWN)
+ false_expr = gen_rtx_fmt_ee (false_code, GET_MODE (true_expr),
+ XEXP (true_expr, 0), XEXP (true_expr, 1));
+ else
+ false_expr = NULL_RTX;
+
+#ifdef IFCVT_MODIFY_TESTS
+ /* If the machine description needs to modify the tests, such as setting a
+ conditional execution register from a comparison, it can do so here. */
+ IFCVT_MODIFY_TESTS (true_expr, false_expr, test_bb, then_bb, else_bb,
+ join_bb);
+
+ /* See if the conversion failed */
+ if (!true_expr || !false_expr)
+ goto fail;
+#endif
+
+ true_prob_val = find_reg_note (test_bb->end, REG_BR_PROB, NULL_RTX);
+ if (true_prob_val)
+ {
+ true_prob_val = XEXP (true_prob_val, 0);
+ false_prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (true_prob_val));
+ }
+ else
+ false_prob_val = NULL_RTX;
/* For IF-THEN-ELSE blocks, we don't allow modifications of the test
on then THEN block. */
to conditional execution. */
if (then_end
- && ! cond_exec_process_insns (then_start, then_end,
- false_expr, then_mod_ok))
+ && (! false_expr
+ || ! cond_exec_process_insns (then_start, then_end, false_expr,
+ false_prob_val, then_mod_ok)))
goto fail;
if (else_bb
&& ! cond_exec_process_insns (else_start, else_end,
- true_expr, TRUE))
+ true_expr, true_prob_val, TRUE))
goto fail;
if (! apply_change_group ())
return FALSE;
+#ifdef IFCVT_MODIFY_FINAL
+ /* Do any machine dependent final modifications */
+ IFCVT_MODIFY_FINAL (test_bb, then_bb, else_bb, join_bb);
+#endif
+
/* Conversion succeeded. */
if (rtl_dump_file)
fprintf (rtl_dump_file, "%d insn%s converted to conditional execution.\n",
return TRUE;
fail:
+#ifdef IFCVT_MODIFY_CANCEL
+ /* Cancel any machine dependent changes. */
+ IFCVT_MODIFY_CANCEL (test_bb, then_bb, else_bb, join_bb);
+#endif
+
cancel_changes (0);
return FALSE;
}
struct noce_if_info
{
+ basic_block test_bb;
rtx insn_a, insn_b;
rtx x, a, b;
rtx jump, cond, cond_earliest;
rtx, rtx, rtx));
static int noce_try_cmove PARAMS ((struct noce_if_info *));
static int noce_try_cmove_arith PARAMS ((struct noce_if_info *));
+static rtx noce_get_alt_condition PARAMS ((struct noce_if_info *,
+ rtx, rtx *));
+static int noce_try_minmax PARAMS ((struct noce_if_info *));
+static int noce_try_abs PARAMS ((struct noce_if_info *));
/* Helper function for noce_try_store_flag*. */
build the store_flag insn directly. */
if (cond_complex)
- cond = XEXP (SET_SRC (PATTERN (if_info->jump)), 0);
+ cond = XEXP (SET_SRC (pc_set (if_info->jump)), 0);
+
+ if (reversep)
+ code = reversed_comparison_code (cond, if_info->jump);
+ else
+ code = GET_CODE (cond);
if ((if_info->cond_earliest == if_info->jump || cond_complex)
&& (normalize == 0 || STORE_FLAG_VALUE == normalize))
{
rtx tmp;
- code = GET_CODE (cond);
- if (reversep)
- code = reverse_condition (code);
-
tmp = gen_rtx_fmt_ee (code, GET_MODE (x), XEXP (cond, 0),
XEXP (cond, 1));
tmp = gen_rtx_SET (VOIDmode, x, tmp);
if (cond_complex)
return NULL_RTX;
- code = GET_CODE (cond);
- if (reversep)
- code = reverse_condition (code);
-
return emit_store_flag (x, code, XEXP (cond, 0),
XEXP (cond, 1), VOIDmode,
(code == LTU || code == LEU
|| code == GEU || code == GTU), normalize);
}
+/* Emit instruction to move an rtx into STRICT_LOW_PART. */
+static void
+noce_emit_move_insn (x, y)
+ rtx x, y;
+{
+ enum machine_mode outmode, inmode;
+ rtx outer, inner;
+ int bitpos;
+
+ if (GET_CODE (x) != STRICT_LOW_PART)
+ {
+ emit_move_insn (x, y);
+ return;
+ }
+
+ outer = XEXP (x, 0);
+ inner = XEXP (outer, 0);
+ outmode = GET_MODE (outer);
+ inmode = GET_MODE (inner);
+ bitpos = SUBREG_BYTE (outer) * BITS_PER_UNIT;
+ store_bit_field (inner, GET_MODE_BITSIZE (outmode), bitpos, outmode, y,
+ GET_MODE_BITSIZE (inmode));
+}
+
/* Convert "if (test) x = 1; else x = 0".
Only try 0 and STORE_FLAG_VALUE here. Other combinations will be
else if (if_info->b == const0_rtx
&& GET_CODE (if_info->a) == CONST_INT
&& INTVAL (if_info->a) == STORE_FLAG_VALUE
- && can_reverse_comparison_p (if_info->cond, if_info->jump))
+ && (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN))
reversep = 1;
else
return FALSE;
if (target)
{
if (target != if_info->x)
- emit_move_insn (if_info->x, target);
+ noce_emit_move_insn (if_info->x, target);
seq = get_insns ();
end_sequence ();
- emit_insns_before (seq, if_info->cond_earliest);
+ emit_insns_before_scope (seq, if_info->jump, INSN_SCOPE (if_info->insn_a));
return TRUE;
}
int reversep;
HOST_WIDE_INT itrue, ifalse, diff, tmp;
int normalize, can_reverse;
+ enum machine_mode mode;
if (! no_new_pseudos
&& GET_CODE (if_info->a) == CONST_INT
&& GET_CODE (if_info->b) == CONST_INT)
{
+ mode = GET_MODE (if_info->x);
ifalse = INTVAL (if_info->a);
itrue = INTVAL (if_info->b);
- diff = itrue - ifalse;
- can_reverse = can_reverse_comparison_p (if_info->cond, if_info->jump);
+ /* Make sure we can represent the difference between the two values. */
+ if ((itrue - ifalse > 0)
+ != ((ifalse < 0) != (itrue < 0) ? ifalse < 0 : ifalse < itrue))
+ return FALSE;
+
+ diff = trunc_int_for_mode (itrue - ifalse, mode);
+
+ can_reverse = (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN);
reversep = 0;
if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
if (reversep)
{
tmp = itrue; itrue = ifalse; ifalse = tmp;
- diff = -diff;
+ diff = trunc_int_for_mode (-diff, mode);
}
start_sequence ();
=> x = 3 + (test == 0); */
if (diff == STORE_FLAG_VALUE || diff == -STORE_FLAG_VALUE)
{
- target = expand_binop (GET_MODE (if_info->x),
- (diff == STORE_FLAG_VALUE
- ? add_optab : sub_optab),
- GEN_INT (ifalse), target, if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (mode,
+ (diff == STORE_FLAG_VALUE
+ ? PLUS : MINUS),
+ GEN_INT (ifalse), target, if_info->x, 0,
+ OPTAB_WIDEN);
}
/* if (test) x = 8; else x = 0;
=> x = (test != 0) << 3; */
else if (ifalse == 0 && (tmp = exact_log2 (itrue)) >= 0)
{
- target = expand_binop (GET_MODE (if_info->x), ashl_optab,
- target, GEN_INT (tmp), if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (mode, ASHIFT,
+ target, GEN_INT (tmp), if_info->x, 0,
+ OPTAB_WIDEN);
}
/* if (test) x = -1; else x = b;
=> x = -(test != 0) | b; */
else if (itrue == -1)
{
- target = expand_binop (GET_MODE (if_info->x), ior_optab,
- target, GEN_INT (ifalse), if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (mode, IOR,
+ target, GEN_INT (ifalse), if_info->x, 0,
+ OPTAB_WIDEN);
}
/* if (test) x = a; else x = b;
=> x = (-(test != 0) & (b - a)) + a; */
else
{
- target = expand_binop (GET_MODE (if_info->x), and_optab,
- target, GEN_INT (diff), if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (mode, AND,
+ target, GEN_INT (diff), if_info->x, 0,
+ OPTAB_WIDEN);
if (target)
- target = expand_binop (GET_MODE (if_info->x), add_optab,
- target, GEN_INT (ifalse), if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (mode, PLUS,
+ target, GEN_INT (ifalse),
+ if_info->x, 0, OPTAB_WIDEN);
}
if (! target)
}
if (target != if_info->x)
- emit_move_insn (if_info->x, target);
+ noce_emit_move_insn (if_info->x, target);
seq = get_insns ();
end_sequence ();
- emit_insns_before (seq, if_info->cond_earliest);
+
+ if (seq_contains_jump (seq))
+ return FALSE;
+
+ emit_insns_before_scope (seq, if_info->jump, INSN_SCOPE (if_info->insn_a));
return TRUE;
}
&& (XEXP (if_info->a, 1) == const1_rtx
|| XEXP (if_info->a, 1) == constm1_rtx)
&& rtx_equal_p (XEXP (if_info->a, 0), if_info->x)
- && can_reverse_comparison_p (if_info->cond, if_info->jump))
+ && (reversed_comparison_code (if_info->cond, if_info->jump)
+ != UNKNOWN))
{
if (STORE_FLAG_VALUE == INTVAL (XEXP (if_info->a, 1)))
subtract = 0, normalize = 0;
1, normalize);
if (target)
- target = expand_binop (GET_MODE (if_info->x),
- subtract ? sub_optab : add_optab,
- if_info->x, target, if_info->x, 0, OPTAB_WIDEN);
+ target = expand_simple_binop (GET_MODE (if_info->x),
+ subtract ? MINUS : PLUS,
+ if_info->x, target, if_info->x,
+ 0, OPTAB_WIDEN);
if (target)
{
if (target != if_info->x)
- emit_move_insn (if_info->x, target);
+ noce_emit_move_insn (if_info->x, target);
seq = get_insns ();
end_sequence ();
- emit_insns_before (seq, if_info->cond_earliest);
+
+ if (seq_contains_jump (seq))
+ return FALSE;
+
+ emit_insns_before_scope (seq, if_info->jump,
+ INSN_SCOPE (if_info->insn_a));
return TRUE;
}
|| STORE_FLAG_VALUE == -1)
&& ((if_info->a == const0_rtx
&& rtx_equal_p (if_info->b, if_info->x))
- || ((reversep = can_reverse_comparison_p (if_info->cond,
- if_info->jump))
+ || ((reversep = (reversed_comparison_code (if_info->cond,
+ if_info->jump)
+ != UNKNOWN))
&& if_info->b == const0_rtx
&& rtx_equal_p (if_info->a, if_info->x))))
{
gen_reg_rtx (GET_MODE (if_info->x)),
reversep, -1);
if (target)
- target = expand_binop (GET_MODE (if_info->x), and_optab,
- if_info->x, target, if_info->x, 0,
- OPTAB_WIDEN);
+ target = expand_simple_binop (GET_MODE (if_info->x), AND,
+ if_info->x, target, if_info->x, 0,
+ OPTAB_WIDEN);
if (target)
{
if (target != if_info->x)
- emit_move_insn (if_info->x, target);
+ noce_emit_move_insn (if_info->x, target);
seq = get_insns ();
end_sequence ();
- emit_insns_before (seq, if_info->cond_earliest);
+
+ if (seq_contains_jump (seq))
+ return FALSE;
+
+ emit_insns_before_scope (seq, if_info->jump,
+ INSN_SCOPE (if_info->insn_a));
return TRUE;
}
if (target)
{
if (target != if_info->x)
- emit_move_insn (if_info->x, target);
+ noce_emit_move_insn (if_info->x, target);
seq = get_insns ();
end_sequence ();
- emit_insns_before (seq, if_info->cond_earliest);
+ emit_insns_before_scope (seq, if_info->jump,
+ INSN_SCOPE (if_info->insn_a));
return TRUE;
}
else
insn_b = if_info->insn_b;
/* Possibly rearrange operands to make things come out more natural. */
- if (can_reverse_comparison_p (if_info->cond, if_info->jump))
+ if (reversed_comparison_code (if_info->cond, if_info->jump) != UNKNOWN)
{
int reversep = 0;
if (rtx_equal_p (b, x))
if (reversep)
{
- code = reverse_condition (code);
+ code = reversed_comparison_code (if_info->cond, if_info->jump);
tmp = a, a = b, b = tmp;
tmp = insn_a, insn_a = insn_b, insn_b = tmp;
}
if (MEM_SCALAR_P (if_info->a) && MEM_SCALAR_P (if_info->b))
MEM_SCALAR_P (tmp) = 1;
if (MEM_ALIAS_SET (if_info->a) == MEM_ALIAS_SET (if_info->b))
- MEM_ALIAS_SET (tmp) = MEM_ALIAS_SET (if_info->a);
+ set_mem_alias_set (tmp, MEM_ALIAS_SET (if_info->a));
+ set_mem_align (tmp,
+ MIN (MEM_ALIGN (if_info->a), MEM_ALIGN (if_info->b)));
- emit_move_insn (if_info->x, tmp);
+ noce_emit_move_insn (if_info->x, tmp);
}
else if (target != x)
- emit_move_insn (x, target);
+ noce_emit_move_insn (x, target);
tmp = get_insns ();
end_sequence ();
- emit_insns_before (tmp, if_info->cond_earliest);
+ emit_insns_before_scope (tmp, if_info->jump, INSN_SCOPE (if_info->insn_a));
return TRUE;
end_seq_and_fail:
return FALSE;
}
+/* For most cases, the simplified condition we found is the best
+ choice, but this is not the case for the min/max/abs transforms.
+ For these we wish to know that it is A or B in the condition. */
+
+static rtx
+noce_get_alt_condition (if_info, target, earliest)
+ struct noce_if_info *if_info;
+ rtx target;
+ rtx *earliest;
+{
+ rtx cond, set, insn;
+ int reverse;
+
+ /* If target is already mentioned in the known condition, return it. */
+ if (reg_mentioned_p (target, if_info->cond))
+ {
+ *earliest = if_info->cond_earliest;
+ return if_info->cond;
+ }
+
+ set = pc_set (if_info->jump);
+ cond = XEXP (SET_SRC (set), 0);
+ reverse
+ = GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (if_info->jump);
+
+ /* If we're looking for a constant, try to make the conditional
+ have that constant in it. There are two reasons why it may
+ not have the constant we want:
+
+ 1. GCC may have needed to put the constant in a register, because
+ the target can't compare directly against that constant. For
+ this case, we look for a SET immediately before the comparison
+ that puts a constant in that register.
+
+ 2. GCC may have canonicalized the conditional, for example
+ replacing "if x < 4" with "if x <= 3". We can undo that (or
+ make equivalent types of changes) to get the constants we need
+ if they're off by one in the right direction. */
+
+ if (GET_CODE (target) == CONST_INT)
+ {
+ enum rtx_code code = GET_CODE (if_info->cond);
+ rtx op_a = XEXP (if_info->cond, 0);
+ rtx op_b = XEXP (if_info->cond, 1);
+ rtx prev_insn;
+
+ /* First, look to see if we put a constant in a register. */
+ prev_insn = PREV_INSN (if_info->cond_earliest);
+ if (prev_insn
+ && INSN_P (prev_insn)
+ && GET_CODE (PATTERN (prev_insn)) == SET)
+ {
+ rtx src = find_reg_equal_equiv_note (prev_insn);
+ if (!src)
+ src = SET_SRC (PATTERN (prev_insn));
+ if (GET_CODE (src) == CONST_INT)
+ {
+ if (rtx_equal_p (op_a, SET_DEST (PATTERN (prev_insn))))
+ op_a = src;
+ else if (rtx_equal_p (op_b, SET_DEST (PATTERN (prev_insn))))
+ op_b = src;
+
+ if (GET_CODE (op_a) == CONST_INT)
+ {
+ rtx tmp = op_a;
+ op_a = op_b;
+ op_b = tmp;
+ code = swap_condition (code);
+ }
+ }
+ }
+
+ /* Now, look to see if we can get the right constant by
+ adjusting the conditional. */
+ if (GET_CODE (op_b) == CONST_INT)
+ {
+ HOST_WIDE_INT desired_val = INTVAL (target);
+ HOST_WIDE_INT actual_val = INTVAL (op_b);
+
+ switch (code)
+ {
+ case LT:
+ if (actual_val == desired_val + 1)
+ {
+ code = LE;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case LE:
+ if (actual_val == desired_val - 1)
+ {
+ code = LT;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case GT:
+ if (actual_val == desired_val - 1)
+ {
+ code = GE;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ case GE:
+ if (actual_val == desired_val + 1)
+ {
+ code = GT;
+ op_b = GEN_INT (desired_val);
+ }
+ break;
+ default:
+ break;
+ }
+ }
+
+ /* If we made any changes, generate a new conditional that is
+ equivalent to what we started with, but has the right
+ constants in it. */
+ if (code != GET_CODE (if_info->cond)
+ || op_a != XEXP (if_info->cond, 0)
+ || op_b != XEXP (if_info->cond, 1))
+ {
+ cond = gen_rtx_fmt_ee (code, GET_MODE (cond), op_a, op_b);
+ *earliest = if_info->cond_earliest;
+ return cond;
+ }
+ }
+
+ cond = canonicalize_condition (if_info->jump, cond, reverse,
+ earliest, target);
+ if (! cond || ! reg_mentioned_p (target, cond))
+ return NULL;
+
+ /* We almost certainly searched back to a different place.
+ Need to re-verify correct lifetimes. */
+
+ /* X may not be mentioned in the range (cond_earliest, jump]. */
+ for (insn = if_info->jump; insn != *earliest; insn = PREV_INSN (insn))
+ if (INSN_P (insn) && reg_mentioned_p (if_info->x, insn))
+ return NULL;
+
+ /* A and B may not be modified in the range [cond_earliest, jump). */
+ for (insn = *earliest; insn != if_info->jump; insn = NEXT_INSN (insn))
+ if (INSN_P (insn)
+ && (modified_in_p (if_info->a, insn)
+ || modified_in_p (if_info->b, insn)))
+ return NULL;
+
+ return cond;
+}
+
+/* Convert "if (a < b) x = a; else x = b;" to "x = min(a, b);", etc. */
+
+static int
+noce_try_minmax (if_info)
+ struct noce_if_info *if_info;
+{
+ rtx cond, earliest, target, seq;
+ enum rtx_code code, op;
+ int unsignedp;
+
+ /* ??? Can't guarantee that expand_binop won't create pseudos. */
+ if (no_new_pseudos)
+ return FALSE;
+
+ /* ??? Reject modes with NaNs or signed zeros since we don't know how
+ they will be resolved with an SMIN/SMAX. It wouldn't be too hard
+ to get the target to tell us... */
+ if (HONOR_SIGNED_ZEROS (GET_MODE (if_info->x))
+ || HONOR_NANS (GET_MODE (if_info->x)))
+ return FALSE;
+
+ cond = noce_get_alt_condition (if_info, if_info->a, &earliest);
+ if (!cond)
+ return FALSE;
+
+ /* Verify the condition is of the form we expect, and canonicalize
+ the comparison code. */
+ code = GET_CODE (cond);
+ if (rtx_equal_p (XEXP (cond, 0), if_info->a))
+ {
+ if (! rtx_equal_p (XEXP (cond, 1), if_info->b))
+ return FALSE;
+ }
+ else if (rtx_equal_p (XEXP (cond, 1), if_info->a))
+ {
+ if (! rtx_equal_p (XEXP (cond, 0), if_info->b))
+ return FALSE;
+ code = swap_condition (code);
+ }
+ else
+ return FALSE;
+
+ /* Determine what sort of operation this is. Note that the code is for
+ a taken branch, so the code->operation mapping appears backwards. */
+ switch (code)
+ {
+ case LT:
+ case LE:
+ case UNLT:
+ case UNLE:
+ op = SMAX;
+ unsignedp = 0;
+ break;
+ case GT:
+ case GE:
+ case UNGT:
+ case UNGE:
+ op = SMIN;
+ unsignedp = 0;
+ break;
+ case LTU:
+ case LEU:
+ op = UMAX;
+ unsignedp = 1;
+ break;
+ case GTU:
+ case GEU:
+ op = UMIN;
+ unsignedp = 1;
+ break;
+ default:
+ return FALSE;
+ }
+
+ start_sequence ();
+
+ target = expand_simple_binop (GET_MODE (if_info->x), op,
+ if_info->a, if_info->b,
+ if_info->x, unsignedp, OPTAB_WIDEN);
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = get_insns ();
+ end_sequence ();
+
+ if (seq_contains_jump (seq))
+ return FALSE;
+
+ emit_insns_before_scope (seq, if_info->jump, INSN_SCOPE (if_info->insn_a));
+ if_info->cond = cond;
+ if_info->cond_earliest = earliest;
+
+ return TRUE;
+}
+
+/* Convert "if (a < 0) x = -a; else x = a;" to "x = abs(a);", etc. */
+
+static int
+noce_try_abs (if_info)
+ struct noce_if_info *if_info;
+{
+ rtx cond, earliest, target, seq, a, b, c;
+ int negate;
+
+ /* ??? Can't guarantee that expand_binop won't create pseudos. */
+ if (no_new_pseudos)
+ return FALSE;
+
+ /* Recognize A and B as constituting an ABS or NABS. */
+ a = if_info->a;
+ b = if_info->b;
+ if (GET_CODE (a) == NEG && rtx_equal_p (XEXP (a, 0), b))
+ negate = 0;
+ else if (GET_CODE (b) == NEG && rtx_equal_p (XEXP (b, 0), a))
+ {
+ c = a; a = b; b = c;
+ negate = 1;
+ }
+ else
+ return FALSE;
+
+ cond = noce_get_alt_condition (if_info, b, &earliest);
+ if (!cond)
+ return FALSE;
+
+ /* Verify the condition is of the form we expect. */
+ if (rtx_equal_p (XEXP (cond, 0), b))
+ c = XEXP (cond, 1);
+ else if (rtx_equal_p (XEXP (cond, 1), b))
+ c = XEXP (cond, 0);
+ else
+ return FALSE;
+
+ /* Verify that C is zero. Search backward through the block for
+ a REG_EQUAL note if necessary. */
+ if (REG_P (c))
+ {
+ rtx insn, note = NULL;
+ for (insn = earliest;
+ insn != if_info->test_bb->head;
+ insn = PREV_INSN (insn))
+ if (INSN_P (insn)
+ && ((note = find_reg_note (insn, REG_EQUAL, c))
+ || (note = find_reg_note (insn, REG_EQUIV, c))))
+ break;
+ if (! note)
+ return FALSE;
+ c = XEXP (note, 0);
+ }
+ if (GET_CODE (c) == MEM
+ && GET_CODE (XEXP (c, 0)) == SYMBOL_REF
+ && CONSTANT_POOL_ADDRESS_P (XEXP (c, 0)))
+ c = get_pool_constant (XEXP (c, 0));
+
+ /* Work around funny ideas get_condition has wrt canonicalization.
+ Note that these rtx constants are known to be CONST_INT, and
+ therefore imply integer comparisons. */
+ if (c == constm1_rtx && GET_CODE (cond) == GT)
+ ;
+ else if (c == const1_rtx && GET_CODE (cond) == LT)
+ ;
+ else if (c != CONST0_RTX (GET_MODE (b)))
+ return FALSE;
+
+ /* Determine what sort of operation this is. */
+ switch (GET_CODE (cond))
+ {
+ case LT:
+ case LE:
+ case UNLT:
+ case UNLE:
+ negate = !negate;
+ break;
+ case GT:
+ case GE:
+ case UNGT:
+ case UNGE:
+ break;
+ default:
+ return FALSE;
+ }
+
+ start_sequence ();
+
+ target = expand_simple_unop (GET_MODE (if_info->x), ABS, b, if_info->x, 0);
+
+ /* ??? It's a quandry whether cmove would be better here, especially
+ for integers. Perhaps combine will clean things up. */
+ if (target && negate)
+ target = expand_simple_unop (GET_MODE (target), NEG, target, if_info->x, 0);
+
+ if (! target)
+ {
+ end_sequence ();
+ return FALSE;
+ }
+
+ if (target != if_info->x)
+ noce_emit_move_insn (if_info->x, target);
+
+ seq = get_insns ();
+ end_sequence ();
+
+ if (seq_contains_jump (seq))
+ return FALSE;
+
+ emit_insns_before_scope (seq, if_info->jump, INSN_SCOPE (if_info->insn_a));
+ if_info->cond = cond;
+ if_info->cond_earliest = earliest;
+
+ return TRUE;
+}
+
/* Look for the condition for the jump first. We'd prefer to avoid
get_condition if we can -- it tries to look back for the contents
of an original compare. On targets that use normal integers for
rtx *earliest;
{
rtx cond;
+ rtx set;
/* If the condition variable is a register and is MODE_INT, accept it.
Otherwise, fall back on get_condition. */
- if (! condjump_p (jump))
+ if (! any_condjump_p (jump))
return NULL_RTX;
- cond = XEXP (SET_SRC (PATTERN (jump)), 0);
+ set = pc_set (jump);
+
+ cond = XEXP (SET_SRC (set), 0);
if (GET_CODE (XEXP (cond, 0)) == REG
&& GET_MODE_CLASS (GET_MODE (XEXP (cond, 0))) == MODE_INT)
{
/* If this branches to JUMP_LABEL when the condition is false,
reverse the condition. */
- if (GET_CODE (XEXP (SET_SRC (PATTERN (jump)), 2)) == LABEL_REF
- && XEXP (XEXP (SET_SRC (PATTERN (jump)), 2), 0) == JUMP_LABEL (jump))
+ if (GET_CODE (XEXP (SET_SRC (set), 2)) == LABEL_REF
+ && XEXP (XEXP (SET_SRC (set), 2), 0) == JUMP_LABEL (jump))
cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
GET_MODE (cond), XEXP (cond, 0),
XEXP (cond, 1));
return cond;
}
+/* Return true if OP is ok for if-then-else processing. */
+
+static int
+noce_operand_ok (op)
+ rtx op;
+{
+ /* We special-case memories, so handle any of them with
+ no address side effects. */
+ if (GET_CODE (op) == MEM)
+ return ! side_effects_p (XEXP (op, 0));
+
+ if (side_effects_p (op))
+ return FALSE;
+
+ return ! may_trap_p (op);
+}
+
/* Given a simple IF-THEN or IF-THEN-ELSE block, attempt to convert it
without using conditional execution. Return TRUE if we were
successful at converting the the block. */
if (! cond)
return FALSE;
+ /* If the conditional jump is more than just a conditional jump,
+ then we can not do if-conversion on this block. */
+ if (! onlyjump_p (jump))
+ return FALSE;
+
/* We must be comparing objects whose modes imply the size. */
if (GET_MODE (XEXP (cond, 0)) == BLKmode)
return FALSE;
|| GET_CODE (insn_b) != INSN
|| (set_b = single_set (insn_b)) == NULL_RTX
|| ! rtx_equal_p (x, SET_DEST (set_b))
- || reg_mentioned_p (x, cond))
+ || reg_mentioned_p (x, cond)
+ || reg_mentioned_p (x, a)
+ || reg_mentioned_p (x, SET_SRC (set_b)))
insn_b = set_b = NULL_RTX;
}
b = (set_b ? SET_SRC (set_b) : x);
{
if (no_new_pseudos)
return FALSE;
- x = gen_reg_rtx (GET_MODE (x));
+ x = gen_reg_rtx (GET_MODE (GET_CODE (x) == STRICT_LOW_PART
+ ? XEXP (x, 0) : x));
}
/* Don't operate on sources that may trap or are volatile. */
- if (side_effects_p (a) || side_effects_p (b)
- || (GET_CODE (a) != MEM && may_trap_p (a))
- || (GET_CODE (b) != MEM && may_trap_p (b)))
+ if (! noce_operand_ok (a) || ! noce_operand_ok (b))
return FALSE;
/* Set up the info block for our subroutines. */
+ if_info.test_bb = test_bb;
if_info.cond = cond;
if_info.jump = jump;
if_info.insn_a = insn_a;
that case don't do anything and let the code below delete INSN_A. */
if (insn_b && else_bb)
{
+ rtx note;
+
if (else_bb && insn_b == else_bb->end)
else_bb->end = PREV_INSN (insn_b);
reorder_insns (insn_b, insn_b, PREV_INSN (if_info.cond_earliest));
+
+ /* If there was a REG_EQUAL note, delete it since it may have been
+ true due to this insn being after a jump. */
+ if ((note = find_reg_note (insn_b, REG_EQUAL, NULL_RTX)) != 0)
+ remove_note (insn_b, note);
+
insn_b = NULL_RTX;
- x = orig_x;
}
+ /* If we have "x = b; if (...) x = a;", and x has side-effects, then
+ x must be executed twice. */
+ else if (insn_b && side_effects_p (orig_x))
+ return FALSE;
+
+ x = orig_x;
goto success;
}
if (noce_try_store_flag (&if_info))
goto success;
+ if (noce_try_minmax (&if_info))
+ goto success;
+ if (noce_try_abs (&if_info))
+ goto success;
if (HAVE_conditional_move
&& noce_try_cmove (&if_info))
goto success;
success:
/* The original sets may now be killed. */
- if (insn_a == then_bb->end)
- then_bb->end = PREV_INSN (insn_a);
- flow_delete_insn (insn_a);
+ delete_insn (insn_a);
/* Several special cases here: First, we may have reused insn_b above,
in which case insn_b is now NULL. Second, we want to delete insn_b
the TEST block, it may in fact be loading data needed for the comparison.
We'll let life_analysis remove the insn if it's really dead. */
if (insn_b && else_bb)
- {
- if (insn_b == else_bb->end)
- else_bb->end = PREV_INSN (insn_b);
- flow_delete_insn (insn_b);
- }
+ delete_insn (insn_b);
- /* The new insns will have been inserted before cond_earliest. We should
+ /* The new insns will have been inserted just before the jump. We should
be able to remove the jump with impunity, but the condition itself may
have been modified by gcse to be shared across basic blocks. */
- test_bb->end = PREV_INSN (jump);
- flow_delete_insn (jump);
+ delete_insn (jump);
/* If we used a temporary, fix it up now. */
if (orig_x != x)
{
start_sequence ();
- emit_move_insn (orig_x, x);
+ noce_emit_move_insn (copy_rtx (orig_x), x);
insn_b = gen_sequence ();
end_sequence ();
- test_bb->end = emit_insn_after (insn_b, test_bb->end);
+ emit_insn_after_scope (insn_b, test_bb->end, INSN_SCOPE (insn_a));
}
/* Merge the blocks! */
/* First merge TEST block into THEN block. This is a no-brainer since
the THEN block did not have a code label to begin with. */
-
- if (combo_bb->global_live_at_end)
- COPY_REG_SET (combo_bb->global_live_at_end, then_bb->global_live_at_end);
- merge_blocks_nomove (combo_bb, then_bb);
- num_removed_blocks++;
+ if (then_bb)
+ {
+ if (combo_bb->global_live_at_end)
+ COPY_REG_SET (combo_bb->global_live_at_end,
+ then_bb->global_live_at_end);
+ merge_blocks_nomove (combo_bb, then_bb);
+ num_removed_blocks++;
+ }
/* The ELSE block, if it existed, had a label. That label count
will almost always be zero, but odd things can happen when labels
get their addresses taken. */
if (else_bb)
{
- if (LABEL_NUSES (else_bb->head) == 0
- && ! LABEL_PRESERVE_P (else_bb->head)
- && ! LABEL_NAME (else_bb->head))
- {
- /* We can merge the ELSE. */
- merge_blocks_nomove (combo_bb, else_bb);
- num_removed_blocks++;
- }
- else
- {
- /* We cannot merge the ELSE. */
-
- /* Properly rewire the edge out of the now combined
- TEST-THEN block to point here. */
- remove_edge (combo_bb->succ);
- if (combo_bb->succ || else_bb->pred)
- abort ();
- make_edge (NULL, combo_bb, else_bb, EDGE_FALLTHRU);
-
- /* Remove the jump and cruft from the end of the TEST-THEN block. */
- tidy_fallthru_edge (combo_bb->succ, combo_bb, else_bb);
-
- /* Make sure we update life info properly. */
- SET_UPDATE_LIFE(combo_bb);
- if (else_bb->global_live_at_end)
- COPY_REG_SET (else_bb->global_live_at_start,
- else_bb->global_live_at_end);
-
- /* The ELSE is the new combo block. */
- combo_bb = else_bb;
- }
+ merge_blocks_nomove (combo_bb, else_bb);
+ num_removed_blocks++;
}
/* If there was no join block reported, that means it was not adjacent
if (! join_bb)
{
+ rtx last = combo_bb->end;
+
/* The outgoing edge for the current COMBO block should already
be correct. Verify this. */
if (combo_bb->succ == NULL_EDGE)
- abort ();
+ {
+ if (find_reg_note (last, REG_NORETURN, NULL))
+ ;
+ else if (GET_CODE (last) == INSN
+ && GET_CODE (PATTERN (last)) == TRAP_IF
+ && TRAP_CONDITION (PATTERN (last)) == const_true_rtx)
+ ;
+ else
+ abort ();
+ }
- /* There should sill be a branch at the end of the THEN or ELSE
+ /* There should still be something at the end of the THEN or ELSE
blocks taking us to our final destination. */
- if (! simplejump_p (combo_bb->end)
- && ! returnjump_p (combo_bb->end))
+ else if (GET_CODE (last) == JUMP_INSN)
+ ;
+ else if (combo_bb->succ->dest == EXIT_BLOCK_PTR
+ && GET_CODE (last) == CALL_INSN
+ && SIBLING_CALL_P (last))
+ ;
+ else if ((combo_bb->succ->flags & EDGE_EH)
+ && can_throw_internal (last))
+ ;
+ else
abort ();
}
- /* The JOIN block had a label. It may have had quite a number
- of other predecessors too, but probably not. See if we can
- merge this with the others. */
- else if (LABEL_NUSES (join_bb->head) == 0
- && ! LABEL_PRESERVE_P (join_bb->head)
- && ! LABEL_NAME (join_bb->head))
+ /* The JOIN block may have had quite a number of other predecessors too.
+ Since we've already merged the TEST, THEN and ELSE blocks, we should
+ have only one remaining edge from our if-then-else diamond. If there
+ is more than one remaining edge, it must come from elsewhere. There
+ may be zero incoming edges if the THEN block didn't actually join
+ back up (as with a call to abort). */
+ else if ((join_bb->pred == NULL
+ || join_bb->pred->pred_next == NULL)
+ && join_bb != EXIT_BLOCK_PTR)
{
/* We can merge the JOIN. */
if (combo_bb->global_live_at_end)
abort ();
/* Remove the jump and cruft from the end of the COMBO block. */
- tidy_fallthru_edge (combo_bb->succ, combo_bb, join_bb);
+ if (join_bb != EXIT_BLOCK_PTR)
+ tidy_fallthru_edge (combo_bb->succ, combo_bb, join_bb);
}
- /* Make sure we update life info properly. */
- SET_UPDATE_LIFE (combo_bb);
-
num_updated_if_blocks++;
}
\f
if (find_if_block (test_bb, then_edge, else_edge))
goto success;
+ if (HAVE_trap && HAVE_conditional_trap
+ && find_cond_trap (test_bb, then_edge, else_edge))
+ goto success;
if (post_dominators
&& (! HAVE_conditional_execution || reload_completed))
{
basic_block join_bb = NULL_BLOCK;
edge then_succ = then_bb->succ;
edge else_succ = else_bb->succ;
- int next_index;
+ basic_block next;
/* The THEN block of an IF-THEN combo must have exactly one predecessor. */
if (then_bb->pred->pred_next != NULL_EDGE)
return FALSE;
- /* The THEN block of an IF-THEN combo must have exactly one successor. */
- if (then_succ == NULL_EDGE
- || then_succ->succ_next != NULL_EDGE
- || (then_succ->flags & EDGE_COMPLEX))
+ /* The THEN block of an IF-THEN combo must have zero or one successors. */
+ if (then_succ != NULL_EDGE
+ && (then_succ->succ_next != NULL_EDGE
+ || (then_succ->flags & EDGE_COMPLEX)))
return FALSE;
- /* The THEN block may not start with a label, as might happen with an
- unused user label that has had its address taken. */
- if (GET_CODE (then_bb->head) == CODE_LABEL)
- return FALSE;
+ /* If the THEN block has no successors, conditional execution can still
+ make a conditional call. Don't do this unless the ELSE block has
+ only one incoming edge -- the CFG manipulation is too ugly otherwise.
+ Check for the last insn of the THEN block being an indirect jump, which
+ is listed as not having any successors, but confuses the rest of the CE
+ code processing. XXX we should fix this in the future. */
+ if (then_succ == NULL)
+ {
+ if (else_bb->pred->pred_next == NULL_EDGE)
+ {
+ rtx last_insn = then_bb->end;
+
+ while (last_insn
+ && GET_CODE (last_insn) == NOTE
+ && last_insn != then_bb->head)
+ last_insn = PREV_INSN (last_insn);
+
+ if (last_insn
+ && GET_CODE (last_insn) == JUMP_INSN
+ && ! simplejump_p (last_insn))
+ return FALSE;
+
+ join_bb = else_bb;
+ else_bb = NULL_BLOCK;
+ }
+ else
+ return FALSE;
+ }
/* If the THEN block's successor is the other edge out of the TEST block,
then we have an IF-THEN combo without an ELSE. */
- if (then_succ->dest == else_bb)
+ else if (then_succ->dest == else_bb)
{
join_bb = else_bb;
else_bb = NULL_BLOCK;
/* Make sure IF, THEN, and ELSE, blocks are adjacent. Actually, we
get the first condition for free, since we've already asserted that
there's a fallthru edge from IF to THEN. */
- /* ??? As an enhancement, move the ELSE block. Have to deal with EH and
+ /* ??? As an enhancement, move the ELSE block. Have to deal with
BLOCK notes, if by no other means than aborting the merge if they
exist. Sticky enough I don't want to think about it now. */
- next_index = then_bb->index;
- if (else_bb && ++next_index != else_bb->index)
+ next = then_bb;
+ if (else_bb && (next = next->next_bb) != else_bb)
return FALSE;
- if (++next_index != join_bb->index)
+ if ((next = next->next_bb) != join_bb && join_bb != EXIT_BLOCK_PTR)
{
if (else_bb)
join_bb = NULL;
return process_if_block (test_bb, then_bb, else_bb, join_bb);
}
+/* Convert a branch over a trap, or a branch to a trap,
+ into a conditional trap. */
+
+static int
+find_cond_trap (test_bb, then_edge, else_edge)
+ basic_block test_bb;
+ edge then_edge, else_edge;
+{
+ basic_block then_bb, else_bb, trap_bb, other_bb;
+ rtx trap, jump, cond, cond_earliest, seq;
+ enum rtx_code code;
+
+ then_bb = then_edge->dest;
+ else_bb = else_edge->dest;
+
+ /* Locate the block with the trap instruction. */
+ /* ??? While we look for no successors, we really ought to allow
+ EH successors. Need to fix merge_if_block for that to work. */
+ if ((trap = block_has_only_trap (then_bb)) != NULL)
+ trap_bb = then_bb, other_bb = else_bb;
+ else if ((trap = block_has_only_trap (else_bb)) != NULL)
+ trap_bb = else_bb, other_bb = then_bb;
+ else
+ return FALSE;
+
+ if (rtl_dump_file)
+ {
+ fprintf (rtl_dump_file, "\nTRAP-IF block found, start %d, trap %d\n",
+ test_bb->index, trap_bb->index);
+ }
+
+ /* If this is not a standard conditional jump, we can't parse it. */
+ jump = test_bb->end;
+ cond = noce_get_condition (jump, &cond_earliest);
+ if (! cond)
+ return FALSE;
+
+ /* If the conditional jump is more than just a conditional jump,
+ then we can not do if-conversion on this block. */
+ if (! onlyjump_p (jump))
+ return FALSE;
+
+ /* We must be comparing objects whose modes imply the size. */
+ if (GET_MODE (XEXP (cond, 0)) == BLKmode)
+ return FALSE;
+
+ /* Reverse the comparison code, if necessary. */
+ code = GET_CODE (cond);
+ if (then_bb == trap_bb)
+ {
+ code = reversed_comparison_code (cond, jump);
+ if (code == UNKNOWN)
+ return FALSE;
+ }
+
+ /* Attempt to generate the conditional trap. */
+ seq = gen_cond_trap (code, XEXP (cond, 0), XEXP (cond, 1),
+ TRAP_CODE (PATTERN (trap)));
+ if (seq == NULL)
+ return FALSE;
+
+ /* Emit the new insns before cond_earliest. */
+ emit_insn_before_scope (seq, cond_earliest, INSN_SCOPE (trap));
+
+ /* Delete the trap block if possible. */
+ remove_edge (trap_bb == then_bb ? then_edge : else_edge);
+ if (trap_bb->pred == NULL)
+ {
+ flow_delete_block (trap_bb);
+ num_removed_blocks++;
+ }
+
+ /* If the non-trap block and the test are now adjacent, merge them.
+ Otherwise we must insert a direct branch. */
+ if (test_bb->next_bb == other_bb)
+ {
+ delete_insn (jump);
+ merge_if_block (test_bb, NULL, NULL, other_bb);
+ }
+ else
+ {
+ rtx lab, newjump;
+
+ lab = JUMP_LABEL (jump);
+ newjump = emit_jump_insn_after (gen_jump (lab), jump);
+ LABEL_NUSES (lab) += 1;
+ JUMP_LABEL (newjump) = lab;
+ emit_barrier_after (newjump);
+
+ delete_insn (jump);
+ }
+
+ return TRUE;
+}
+
+/* Subroutine of find_cond_trap: if BB contains only a trap insn,
+ return it. */
+
+static rtx
+block_has_only_trap (bb)
+ basic_block bb;
+{
+ rtx trap;
+
+ /* We're not the exit block. */
+ if (bb == EXIT_BLOCK_PTR)
+ return NULL_RTX;
+
+ /* The block must have no successors. */
+ if (bb->succ)
+ return NULL_RTX;
+
+ /* The only instruction in the THEN block must be the trap. */
+ trap = first_active_insn (bb);
+ if (! (trap == bb->end
+ && GET_CODE (PATTERN (trap)) == TRAP_IF
+ && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx))
+ return NULL_RTX;
+
+ return trap;
+}
+
/* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is
transformable, but not necessarily the other. There need be no
JOIN block.
edge then_edge, else_edge;
{
basic_block then_bb = then_edge->dest;
- basic_block else_bb = else_edge->dest;
+ basic_block else_bb = else_edge->dest, new_bb;
edge then_succ = then_bb->succ;
- rtx new_lab;
+ int then_bb_index;
/* THEN has one successor. */
if (!then_succ || then_succ->succ_next != NULL)
if (then_bb->pred->pred_next != NULL)
return FALSE;
- /* THEN has no label. */
- if (GET_CODE (then_bb->head) == CODE_LABEL)
- return FALSE;
-
- /* ELSE follows THEN. (??? could be moved) */
- if (else_bb->index != then_bb->index + 1)
+ /* THEN must do something. */
+ if (forwarder_block_p (then_bb))
return FALSE;
num_possible_if_blocks++;
if (count_bb_insns (then_bb) > BRANCH_COST)
return FALSE;
- /* Find the label for THEN's destination. */
- if (then_succ->dest == EXIT_BLOCK_PTR)
- new_lab = NULL_RTX;
- else
- {
- new_lab = JUMP_LABEL (then_bb->end);
- if (! new_lab)
- abort ();
- }
-
/* Registers set are dead, or are predicable. */
- if (! dead_or_predicable (test_bb, then_bb, else_bb, new_lab, 1))
+ if (! dead_or_predicable (test_bb, then_bb, else_bb,
+ then_bb->succ->dest, 1))
return FALSE;
/* Conversion went ok, including moving the insns and fixing up the
jump. Adjust the CFG to match. */
- SET_UPDATE_LIFE (test_bb);
bitmap_operation (test_bb->global_live_at_end,
else_bb->global_live_at_start,
then_bb->global_live_at_end, BITMAP_IOR);
- make_edge (NULL, test_bb, then_succ->dest, 0);
+ new_bb = redirect_edge_and_branch_force (FALLTHRU_EDGE (test_bb), else_bb);
+ then_bb_index = then_bb->index;
flow_delete_block (then_bb);
- tidy_fallthru_edge (else_edge, test_bb, else_bb);
+ /* Make rest of code believe that the newly created block is the THEN_BB
+ block we removed. */
+ if (new_bb)
+ {
+ new_bb->index = then_bb_index;
+ BASIC_BLOCK (then_bb_index) = new_bb;
+ }
+ /* We've possibly created jump to next insn, cleanup_cfg will solve that
+ later. */
num_removed_blocks++;
num_updated_if_blocks++;
basic_block then_bb = then_edge->dest;
basic_block else_bb = else_edge->dest;
edge else_succ = else_bb->succ;
- rtx new_lab, note;
+ rtx note;
/* ELSE has one successor. */
if (!else_succ || else_succ->succ_next != NULL)
if (else_bb->pred->pred_next != NULL)
return FALSE;
- /* ELSE has a label we can delete. */
- if (LABEL_NUSES (else_bb->head) > 1
- || LABEL_PRESERVE_P (else_bb->head)
- || LABEL_NAME (else_bb->head))
+ /* THEN is not EXIT. */
+ if (then_bb->index < 0)
return FALSE;
/* ELSE is predicted or SUCC(ELSE) postdominates THEN. */
if (note && INTVAL (XEXP (note, 0)) >= REG_BR_PROB_BASE / 2)
;
else if (else_succ->dest->index < 0
- || (then_bb->index >= 0
- && TEST_BIT (post_dominators[ORIG_INDEX (then_bb)],
- ORIG_INDEX (else_succ->dest))))
+ || TEST_BIT (post_dominators[then_bb->index],
+ else_succ->dest->index))
;
else
return FALSE;
if (count_bb_insns (then_bb) > BRANCH_COST)
return FALSE;
- /* Find the label for ELSE's destination. */
- if (else_succ->dest == EXIT_BLOCK_PTR)
- new_lab = NULL_RTX;
- else
- {
- if (else_succ->flags & EDGE_FALLTHRU)
- {
- new_lab = else_succ->dest->head;
- if (GET_CODE (new_lab) != CODE_LABEL)
- abort ();
- }
- else
- {
- new_lab = JUMP_LABEL (else_bb->end);
- if (! new_lab)
- abort ();
- }
- }
-
/* Registers set are dead, or are predicable. */
- if (! dead_or_predicable (test_bb, else_bb, then_bb, new_lab, 0))
+ if (! dead_or_predicable (test_bb, else_bb, then_bb, else_succ->dest, 0))
return FALSE;
/* Conversion went ok, including moving the insns and fixing up the
jump. Adjust the CFG to match. */
- SET_UPDATE_LIFE (test_bb);
bitmap_operation (test_bb->global_live_at_end,
then_bb->global_live_at_start,
else_bb->global_live_at_end, BITMAP_IOR);
- remove_edge (else_edge);
- make_edge (NULL, test_bb, else_succ->dest, 0);
flow_delete_block (else_bb);
num_removed_blocks++;
static int
dead_or_predicable (test_bb, merge_bb, other_bb, new_dest, reversep)
basic_block test_bb, merge_bb, other_bb;
- rtx new_dest;
+ basic_block new_dest;
int reversep;
{
- rtx head, end, jump, earliest, old_dest;
+ rtx head, end, jump, earliest, old_dest, new_label = NULL_RTX;
jump = test_bb->end;
end = PREV_INSN (end);
}
+ /* Disable handling dead code by conditional execution if the machine needs
+ to do anything funny with the tests, etc. */
+#ifndef IFCVT_MODIFY_TESTS
if (HAVE_conditional_execution)
{
/* In the conditional execution case, we have things easy. We know
All that's left is making sure the insns involved can actually
be predicated. */
- rtx cond;
+ rtx cond, prob_val;
cond = cond_exec_get_condition (jump);
+ if (! cond)
+ return FALSE;
+
+ prob_val = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
+ if (prob_val)
+ prob_val = XEXP (prob_val, 0);
+
if (reversep)
- cond = gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond)),
- GET_MODE (cond), XEXP (cond, 0),
- XEXP (cond, 1));
+ {
+ enum rtx_code rev = reversed_comparison_code (cond, jump);
+ if (rev == UNKNOWN)
+ return FALSE;
+ cond = gen_rtx_fmt_ee (rev, GET_MODE (cond), XEXP (cond, 0),
+ XEXP (cond, 1));
+ if (prob_val)
+ prob_val = GEN_INT (REG_BR_PROB_BASE - INTVAL (prob_val));
+ }
- if (! cond_exec_process_insns (head, end, cond, 0))
+ if (! cond_exec_process_insns (head, end, cond, prob_val, 0))
goto cancel;
earliest = jump;
}
else
+#endif
{
/* In the non-conditional execution case, we have to verify that there
are no trapping operations, no calls, no references to memory, and
/* ??? Even non-trapping memories such as stack frame
references must be avoided. For stores, we collect
no lifetime info; for reads, we'd have to assert
- true_dependance false against every store in the
+ true_dependence false against every store in the
TEST range. */
if (for_each_rtx (&PATTERN (insn), find_memory, NULL))
return FALSE;
break;
}
- if (! condjump_p (jump))
+ if (! any_condjump_p (jump))
return FALSE;
/* Find the extent of the conditional. */
/* ??? bb->local_set is only valid during calculate_global_regs_live,
so we must recompute usage for MERGE_BB. Not so bad, I suppose,
since we've already asserted that MERGE_BB is small. */
- propagate_block (merge_bb, tmp, merge_set, 0);
+ propagate_block (merge_bb, tmp, merge_set, merge_set, 0);
/* For small register class machines, don't lengthen lifetimes of
hard registers before reload. */
Moreover, we're interested in the insns live from OTHER_BB. */
COPY_REG_SET (test_live, other_bb->global_live_at_start);
- pbi = init_propagate_block_info (test_bb, test_live, test_set, 0);
+ pbi = init_propagate_block_info (test_bb, test_live, test_set, test_set,
+ 0);
for (insn = jump; ; insn = prev)
{
change group management. */
old_dest = JUMP_LABEL (jump);
- if (reversep
- ? ! invert_jump_1 (jump, new_dest)
- : ! redirect_jump_1 (jump, new_dest))
- goto cancel;
+ if (other_bb != new_dest)
+ {
+ new_label = block_label (new_dest);
+ if (reversep
+ ? ! invert_jump_1 (jump, new_label)
+ : ! redirect_jump_1 (jump, new_label))
+ goto cancel;
+ }
if (! apply_change_group ())
return FALSE;
- if (old_dest)
- LABEL_NUSES (old_dest) -= 1;
- if (new_dest)
- LABEL_NUSES (new_dest) += 1;
- JUMP_LABEL (jump) = new_dest;
-
- if (reversep)
+ if (other_bb != new_dest)
{
- rtx note = find_reg_note (jump, REG_BR_PROB, NULL_RTX);
- if (note)
- XEXP (note, 0) = GEN_INT (REG_BR_PROB_BASE - INTVAL (XEXP (note, 0)));
+ if (old_dest)
+ LABEL_NUSES (old_dest) -= 1;
+ if (new_label)
+ LABEL_NUSES (new_label) += 1;
+ JUMP_LABEL (jump) = new_label;
+ if (reversep)
+ invert_br_probabilities (jump);
+
+ redirect_edge_succ (BRANCH_EDGE (test_bb), new_dest);
+ if (reversep)
+ {
+ gcov_type count, probability;
+ count = BRANCH_EDGE (test_bb)->count;
+ BRANCH_EDGE (test_bb)->count = FALLTHRU_EDGE (test_bb)->count;
+ FALLTHRU_EDGE (test_bb)->count = count;
+ probability = BRANCH_EDGE (test_bb)->probability;
+ BRANCH_EDGE (test_bb)->probability
+ = FALLTHRU_EDGE (test_bb)->probability;
+ FALLTHRU_EDGE (test_bb)->probability = probability;
+ update_br_prob_note (test_bb);
+ }
}
/* Move the insns out of MERGE_BB to before the branch. */
if (end == merge_bb->end)
merge_bb->end = PREV_INSN (head);
- head = squeeze_notes (head, end);
- if (GET_CODE (end) == NOTE
- && (NOTE_LINE_NUMBER (end) == NOTE_INSN_BLOCK_END
- || NOTE_LINE_NUMBER (end) == NOTE_INSN_BLOCK_BEG
- || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_BEG
- || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_END
- || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_CONT
- || NOTE_LINE_NUMBER (end) == NOTE_INSN_LOOP_VTOP))
- {
- if (head == end)
- return TRUE;
- end = PREV_INSN (end);
- }
+ if (squeeze_notes (&head, &end))
+ return TRUE;
reorder_insns (head, end, PREV_INSN (earliest));
}
+
+ /* Remove the jump and edge if we can. */
+ if (other_bb == new_dest)
+ {
+ delete_insn (jump);
+ remove_edge (BRANCH_EDGE (test_bb));
+ /* ??? Can't merge blocks here, as then_bb is still in use.
+ At minimum, the merge will get done just before bb-reorder. */
+ }
+
return TRUE;
cancel:
/* Main entry point for all if-conversion. */
void
-if_convert (life_data_ok)
- int life_data_ok;
+if_convert (x_life_data_ok)
+ int x_life_data_ok;
{
- int block_num;
+ basic_block bb;
num_possible_if_blocks = 0;
num_updated_if_blocks = 0;
num_removed_blocks = 0;
+ life_data_ok = (x_life_data_ok != 0);
/* Free up basic_block_for_insn so that we don't have to keep it
up to date, either here or in merge_blocks_nomove. */
post_dominators = NULL;
if (HAVE_conditional_execution || life_data_ok)
{
- post_dominators = sbitmap_vector_alloc (n_basic_blocks, n_basic_blocks);
- compute_flow_dominators (NULL, post_dominators);
+ post_dominators = sbitmap_vector_alloc (last_basic_block, last_basic_block);
+ calculate_dominance_info (NULL, post_dominators, CDI_POST_DOMINATORS);
}
-
- /* Record initial block numbers. */
- for (block_num = 0; block_num < n_basic_blocks; block_num++)
- SET_ORIG_INDEX (BASIC_BLOCK (block_num), block_num);
+ if (life_data_ok)
+ clear_bb_flags ();
/* Go through each of the basic blocks looking for things to convert. */
- for (block_num = 0; block_num < n_basic_blocks; )
- {
- basic_block bb = BASIC_BLOCK (block_num);
- if (find_if_header (bb))
- block_num = bb->index;
- else
- block_num++;
- }
+ FOR_EACH_BB (bb)
+ while (find_if_header (bb))
+ continue;
- sbitmap_vector_free (post_dominators);
+ if (post_dominators)
+ sbitmap_vector_free (post_dominators);
if (rtl_dump_file)
fflush (rtl_dump_file);
- /* Rebuild basic_block_for_insn for update_life_info and for gcse. */
- compute_bb_for_insn (get_max_uid ());
+ clear_aux_for_blocks ();
/* Rebuild life info for basic blocks that require it. */
if (num_removed_blocks && life_data_ok)
{
- sbitmap update_life_blocks = sbitmap_alloc (n_basic_blocks);
- sbitmap_zero (update_life_blocks);
-
/* If we allocated new pseudos, we must resize the array for sched1. */
if (max_regno < max_reg_num ())
{
max_regno = max_reg_num ();
allocate_reg_info (max_regno, FALSE, FALSE);
}
-
- for (block_num = 0; block_num < n_basic_blocks; block_num++)
- if (UPDATE_LIFE (BASIC_BLOCK (block_num)))
- SET_BIT (update_life_blocks, block_num);
-
- count_or_remove_death_notes (update_life_blocks, 1);
- update_life_info (update_life_blocks, UPDATE_LIFE_LOCAL,
- PROP_DEATH_NOTES);
-
- sbitmap_free (update_life_blocks);
+ update_life_info_in_dirty_blocks (UPDATE_LIFE_GLOBAL_RM_NOTES,
+ PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE
+ | PROP_KILL_DEAD_CODE);
}
/* Write the final stats. */
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