X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=blobdiff_plain;f=gcc%2Floop-iv.c;h=83d25015976875746ef0fc71fe793ba1b2b7577c;hp=19da19927b1b4e57e6f70ac67fed0af751cec9f6;hb=e3a07cda8df51224d900667a50dc87bfffde1fa9;hpb=dd9b9fc5724f3fa5479caad68d2050621cb4e0a6
diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index 19da19927b1..83d25015976 100644
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -1,31 +1,32 @@
/* Rtl-level induction variable analysis.
- Copyright (C) 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
-
+ Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
+ Free Software Foundation, Inc.
+
This file is part of GCC.
-
+
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
+Free Software Foundation; either version 3, or (at your option) any
later version.
-
+
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 GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
-02110-1301, USA. */
+along with GCC; see the file COPYING3. If not see
+. */
/* This is a simple analysis of induction variables of the loop. The major use
is for determining the number of iterations of a loop for loop unrolling,
doloop optimization and branch prediction. The iv information is computed
on demand.
- Induction variable is analyzed by walking the use-def chains. When a biv
- is found, it is cached in the bivs hash table. When register is proved
- to be a giv, its description is stored to DF_REF_DATA of the def reference.
+ Induction variables are analyzed by walking the use-def chains. When
+ a basic induction variable (biv) is found, it is cached in the bivs
+ hash table. When register is proved to be a biv, its description
+ is stored to DF_REF_DATA of the def reference.
The analysis works always with one loop -- you must call
iv_analysis_loop_init (loop) for it. All the other functions then work with
@@ -34,7 +35,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
iv_analysis_done () to clean up the memory.
The available functions are:
-
+
iv_analyze (insn, reg, iv): Stores the description of the induction variable
corresponding to the use of register REG in INSN to IV. Returns true if
REG is an induction variable in INSN. false otherwise.
@@ -59,7 +60,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
#include "expr.h"
#include "intl.h"
#include "output.h"
-#include "toplev.h"
+#include "diagnostic-core.h"
#include "df.h"
#include "hashtab.h"
@@ -167,15 +168,14 @@ lowpart_subreg (enum machine_mode outer_mode, rtx expr,
subreg_lowpart_offset (outer_mode, inner_mode));
}
-static void
+static void
check_iv_ref_table_size (void)
{
if (iv_ref_table_size < DF_DEFS_TABLE_SIZE())
{
unsigned int new_size = DF_DEFS_TABLE_SIZE () + (DF_DEFS_TABLE_SIZE () / 4);
- iv_ref_table = xrealloc (iv_ref_table,
- sizeof (struct rtx_iv *) * new_size);
- memset (&iv_ref_table[iv_ref_table_size], 0,
+ iv_ref_table = XRESIZEVEC (struct rtx_iv *, iv_ref_table, new_size);
+ memset (&iv_ref_table[iv_ref_table_size], 0,
(new_size - iv_ref_table_size) * sizeof (struct rtx_iv *));
iv_ref_table_size = new_size;
}
@@ -278,10 +278,11 @@ iv_analysis_loop_init (struct loop *loop)
df_remove_problem (df_chain);
df_process_deferred_rescans ();
df_chain_add_problem (DF_UD_CHAIN);
+ df_note_add_problem ();
df_set_blocks (blocks);
df_analyze ();
if (dump_file)
- df_dump (dump_file);
+ df_dump_region (dump_file);
check_iv_ref_table_size ();
BITMAP_FREE (blocks);
@@ -294,15 +295,16 @@ iv_analysis_loop_init (struct loop *loop)
is set to NULL and true is returned. */
static bool
-latch_dominating_def (rtx reg, struct df_ref **def)
+latch_dominating_def (rtx reg, df_ref *def)
{
- struct df_ref *single_rd = NULL, *adef;
+ df_ref single_rd = NULL, adef;
unsigned regno = REGNO (reg);
struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (current_loop->latch);
- for (adef = DF_REG_DEF_CHAIN (regno); adef; adef = adef->next_reg)
+ for (adef = DF_REG_DEF_CHAIN (regno); adef; adef = DF_REF_NEXT_REG (adef))
{
- if (!bitmap_bit_p (bb_info->out, DF_REF_ID (adef)))
+ if (!bitmap_bit_p (df->blocks_to_analyze, DF_REF_BBNO (adef))
+ || !bitmap_bit_p (&bb_info->out, DF_REF_ID (adef)))
continue;
/* More than one reaching definition. */
@@ -322,13 +324,13 @@ latch_dominating_def (rtx reg, struct df_ref **def)
/* Gets definition of REG reaching its use in INSN and stores it to DEF. */
static enum iv_grd_result
-iv_get_reaching_def (rtx insn, rtx reg, struct df_ref **def)
+iv_get_reaching_def (rtx insn, rtx reg, df_ref *def)
{
- struct df_ref *use, *adef;
+ df_ref use, adef;
basic_block def_bb, use_bb;
rtx def_insn;
bool dom_p;
-
+
*def = NULL;
if (!simple_reg_p (reg))
return GRD_INVALID;
@@ -349,7 +351,7 @@ iv_get_reaching_def (rtx insn, rtx reg, struct df_ref **def)
adef = DF_REF_CHAIN (use)->ref;
/* We do not handle setting only part of the register. */
- if (adef->flags & DF_REF_READ_WRITE)
+ if (DF_REF_FLAGS (adef) & DF_REF_READ_WRITE)
return GRD_INVALID;
def_insn = DF_REF_INSN (adef);
@@ -616,7 +618,7 @@ iv_shift (struct rtx_iv *iv, rtx mby)
at get_biv_step. */
static bool
-get_biv_step_1 (struct df_ref *def, rtx reg,
+get_biv_step_1 (df_ref def, rtx reg,
rtx *inner_step, enum machine_mode *inner_mode,
enum rtx_code *extend, enum machine_mode outer_mode,
rtx *outer_step)
@@ -625,7 +627,7 @@ get_biv_step_1 (struct df_ref *def, rtx reg,
rtx next, nextr, tmp;
enum rtx_code code;
rtx insn = DF_REF_INSN (def);
- struct df_ref *next_def;
+ df_ref next_def;
enum iv_grd_result res;
set = single_set (insn);
@@ -783,7 +785,7 @@ get_biv_step_1 (struct df_ref *def, rtx reg,
LAST_DEF is the definition of REG that dominates loop latch. */
static bool
-get_biv_step (struct df_ref *last_def, rtx reg, rtx *inner_step,
+get_biv_step (df_ref last_def, rtx reg, rtx *inner_step,
enum machine_mode *inner_mode, enum rtx_code *extend,
enum machine_mode *outer_mode, rtx *outer_step)
{
@@ -803,7 +805,7 @@ get_biv_step (struct df_ref *last_def, rtx reg, rtx *inner_step,
/* Records information that DEF is induction variable IV. */
static void
-record_iv (struct df_ref *def, struct rtx_iv *iv)
+record_iv (df_ref def, struct rtx_iv *iv)
{
struct rtx_iv *recorded_iv = XNEW (struct rtx_iv);
@@ -818,7 +820,8 @@ record_iv (struct df_ref *def, struct rtx_iv *iv)
static bool
analyzed_for_bivness_p (rtx def, struct rtx_iv *iv)
{
- struct biv_entry *biv = htab_find_with_hash (bivs, def, REGNO (def));
+ struct biv_entry *biv =
+ (struct biv_entry *) htab_find_with_hash (bivs, def, REGNO (def));
if (!biv)
return false;
@@ -848,7 +851,7 @@ iv_analyze_biv (rtx def, struct rtx_iv *iv)
rtx inner_step, outer_step;
enum machine_mode inner_mode, outer_mode;
enum rtx_code extend;
- struct df_ref *last_def;
+ df_ref last_def;
if (dump_file)
{
@@ -856,7 +859,7 @@ iv_analyze_biv (rtx def, struct rtx_iv *iv)
print_rtl (dump_file, def);
fprintf (dump_file, " for bivness.\n");
}
-
+
if (!REG_P (def))
{
if (!CONSTANT_P (def))
@@ -916,7 +919,7 @@ iv_analyze_biv (rtx def, struct rtx_iv *iv)
return iv->base != NULL_RTX;
}
-/* Analyzes expression RHS used at INSN and stores the result to *IV.
+/* Analyzes expression RHS used at INSN and stores the result to *IV.
The mode of the induction variable is MODE. */
bool
@@ -940,7 +943,7 @@ iv_analyze_expr (rtx insn, rtx rhs, enum machine_mode mode, struct rtx_iv *iv)
{
if (!iv_analyze_op (insn, rhs, iv))
return false;
-
+
if (iv->mode == VOIDmode)
{
iv->mode = mode;
@@ -1041,7 +1044,7 @@ iv_analyze_expr (rtx insn, rtx rhs, enum machine_mode mode, struct rtx_iv *iv)
/* Analyzes iv DEF and stores the result to *IV. */
static bool
-iv_analyze_def (struct df_ref *def, struct rtx_iv *iv)
+iv_analyze_def (df_ref def, struct rtx_iv *iv)
{
rtx insn = DF_REF_INSN (def);
rtx reg = DF_REF_REG (def);
@@ -1054,7 +1057,7 @@ iv_analyze_def (struct df_ref *def, struct rtx_iv *iv)
fprintf (dump_file, " in insn ");
print_rtl_single (dump_file, insn);
}
-
+
check_iv_ref_table_size ();
if (DF_REF_IV (def))
{
@@ -1106,7 +1109,7 @@ iv_analyze_def (struct df_ref *def, struct rtx_iv *iv)
static bool
iv_analyze_op (rtx insn, rtx op, struct rtx_iv *iv)
{
- struct df_ref *def = NULL;
+ df_ref def = NULL;
enum iv_grd_result res;
if (dump_file)
@@ -1117,7 +1120,7 @@ iv_analyze_op (rtx insn, rtx op, struct rtx_iv *iv)
print_rtl_single (dump_file, insn);
}
- if (CONSTANT_P (op))
+ if (function_invariant_p (op))
res = GRD_INVARIANT;
else if (GET_CODE (op) == SUBREG)
{
@@ -1189,7 +1192,7 @@ iv_analyze (rtx insn, rtx val, struct rtx_iv *iv)
bool
iv_analyze_result (rtx insn, rtx def, struct rtx_iv *iv)
{
- struct df_ref *adef;
+ df_ref adef;
adef = df_find_def (insn, def);
if (!adef)
@@ -1206,7 +1209,7 @@ bool
biv_p (rtx insn, rtx reg)
{
struct rtx_iv iv;
- struct df_ref *def, *last_def;
+ df_ref def, last_def;
if (!simple_reg_p (reg))
return false;
@@ -1267,7 +1270,7 @@ iv_analysis_done (void)
{
clear_iv_info ();
clean_slate = true;
- df_finish_pass ();
+ df_finish_pass (true);
htab_delete (bivs);
free (iv_ref_table);
iv_ref_table = NULL;
@@ -1303,20 +1306,20 @@ altered_reg_used (rtx *reg, void *alt)
if (!REG_P (*reg))
return 0;
- return REGNO_REG_SET_P (alt, REGNO (*reg));
+ return REGNO_REG_SET_P ((bitmap) alt, REGNO (*reg));
}
/* Marks registers altered by EXPR in set ALT. */
static void
-mark_altered (rtx expr, rtx by ATTRIBUTE_UNUSED, void *alt)
+mark_altered (rtx expr, const_rtx by ATTRIBUTE_UNUSED, void *alt)
{
if (GET_CODE (expr) == SUBREG)
expr = SUBREG_REG (expr);
if (!REG_P (expr))
return;
- SET_REGNO_REG_SET (alt, REGNO (expr));
+ SET_REGNO_REG_SET ((bitmap) alt, REGNO (expr));
}
/* Checks whether RHS is simple enough to process. */
@@ -1326,7 +1329,7 @@ simple_rhs_p (rtx rhs)
{
rtx op0, op1;
- if (CONSTANT_P (rhs)
+ if (function_invariant_p (rhs)
|| (REG_P (rhs) && !HARD_REGISTER_P (rhs)))
return true;
@@ -1334,54 +1337,106 @@ simple_rhs_p (rtx rhs)
{
case PLUS:
case MINUS:
+ case AND:
op0 = XEXP (rhs, 0);
op1 = XEXP (rhs, 1);
- /* Allow reg + const sets only. */
- if (REG_P (op0) && !HARD_REGISTER_P (op0) && CONSTANT_P (op1))
- return true;
- if (REG_P (op1) && !HARD_REGISTER_P (op1) && CONSTANT_P (op0))
- return true;
+ /* Allow reg OP const and reg OP reg. */
+ if (!(REG_P (op0) && !HARD_REGISTER_P (op0))
+ && !function_invariant_p (op0))
+ return false;
+ if (!(REG_P (op1) && !HARD_REGISTER_P (op1))
+ && !function_invariant_p (op1))
+ return false;
- return false;
+ return true;
+
+ case ASHIFT:
+ case ASHIFTRT:
+ case LSHIFTRT:
+ case MULT:
+ op0 = XEXP (rhs, 0);
+ op1 = XEXP (rhs, 1);
+ /* Allow reg OP const. */
+ if (!(REG_P (op0) && !HARD_REGISTER_P (op0)))
+ return false;
+ if (!function_invariant_p (op1))
+ return false;
+
+ return true;
default:
return false;
}
}
-/* Simplifies *EXPR using assignment in INSN. ALTERED is the set of registers
- altered so far. */
+/* If REG has a single definition, replace it with its known value in EXPR.
+ Callback for for_each_rtx. */
-static void
-simplify_using_assignment (rtx insn, rtx *expr, regset altered)
+static int
+replace_single_def_regs (rtx *reg, void *expr1)
{
- rtx set = single_set (insn);
- rtx lhs = NULL_RTX, rhs;
- bool ret = false;
+ unsigned regno;
+ df_ref adef;
+ rtx set, src;
+ rtx *expr = (rtx *)expr1;
- if (set)
- {
- lhs = SET_DEST (set);
- if (!REG_P (lhs)
- || altered_reg_used (&lhs, altered))
- ret = true;
- }
- else
- ret = true;
+ if (!REG_P (*reg))
+ return 0;
- note_stores (PATTERN (insn), mark_altered, altered);
- if (CALL_P (insn))
+ regno = REGNO (*reg);
+ for (;;)
{
- int i;
+ rtx note;
+ adef = DF_REG_DEF_CHAIN (regno);
+ if (adef == NULL || DF_REF_NEXT_REG (adef) != NULL
+ || DF_REF_IS_ARTIFICIAL (adef))
+ return -1;
+
+ set = single_set (DF_REF_INSN (adef));
+ if (set == NULL || !REG_P (SET_DEST (set))
+ || REGNO (SET_DEST (set)) != regno)
+ return -1;
+
+ note = find_reg_equal_equiv_note (DF_REF_INSN (adef));
- /* Kill all call clobbered registers. */
- for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
- if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
- SET_REGNO_REG_SET (altered, i);
+ if (note && function_invariant_p (XEXP (note, 0)))
+ {
+ src = XEXP (note, 0);
+ break;
+ }
+ src = SET_SRC (set);
+
+ if (REG_P (src))
+ {
+ regno = REGNO (src);
+ continue;
+ }
+ break;
}
+ if (!function_invariant_p (src))
+ return -1;
- if (ret)
- return;
+ *expr = simplify_replace_rtx (*expr, *reg, src);
+ return 1;
+}
+
+/* A subroutine of simplify_using_initial_values, this function examines INSN
+ to see if it contains a suitable set that we can use to make a replacement.
+ If it is suitable, return true and set DEST and SRC to the lhs and rhs of
+ the set; return false otherwise. */
+
+static bool
+suitable_set_for_replacement (rtx insn, rtx *dest, rtx *src)
+{
+ rtx set = single_set (insn);
+ rtx lhs = NULL_RTX, rhs;
+
+ if (!set)
+ return false;
+
+ lhs = SET_DEST (set);
+ if (!REG_P (lhs))
+ return false;
rhs = find_reg_equal_equiv_note (insn);
if (rhs)
@@ -1390,12 +1445,25 @@ simplify_using_assignment (rtx insn, rtx *expr, regset altered)
rhs = SET_SRC (set);
if (!simple_rhs_p (rhs))
- return;
+ return false;
- if (for_each_rtx (&rhs, altered_reg_used, altered))
- return;
+ *dest = lhs;
+ *src = rhs;
+ return true;
+}
- *expr = simplify_replace_rtx (*expr, lhs, rhs);
+/* Using the data returned by suitable_set_for_replacement, replace DEST
+ with SRC in *EXPR and return the new expression. Also call
+ replace_single_def_regs if the replacement changed something. */
+static void
+replace_in_expr (rtx *expr, rtx dest, rtx src)
+{
+ rtx old = *expr;
+ *expr = simplify_replace_rtx (*expr, dest, src);
+ if (old == *expr)
+ return;
+ while (for_each_rtx (expr, replace_single_def_regs, expr) != 0)
+ continue;
}
/* Checks whether A implies B. */
@@ -1500,11 +1568,11 @@ implies_p (rtx a, rtx b)
/* A != N is equivalent to A - (N + 1) 0. */
if (GET_CODE (a) == NE
- && GET_CODE (op1) == CONST_INT)
+ && CONST_INT_P (op1))
{
if (GET_CODE (b) == GTU
&& GET_CODE (opb0) == PLUS
&& opb1 == const0_rtx
- && GET_CODE (XEXP (opb0, 1)) == CONST_INT
+ && CONST_INT_P (XEXP (opb0, 1))
/* Avoid overflows. */
&& ((unsigned HOST_WIDE_INT) INTVAL (XEXP (opb0, 1))
!= ((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1)))
@@ -1528,7 +1596,7 @@ implies_p (rtx a, rtx b)
if (GET_CODE (b) == GEU
&& GET_CODE (opb0) == PLUS
&& opb1 == const1_rtx
- && GET_CODE (XEXP (opb0, 1)) == CONST_INT
+ && CONST_INT_P (XEXP (opb0, 1))
/* Avoid overflows. */
&& ((unsigned HOST_WIDE_INT) INTVAL (XEXP (opb0, 1))
!= ((unsigned HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT - 1)))
@@ -1538,11 +1606,12 @@ implies_p (rtx a, rtx b)
/* A >s X, where X is positive, implies A = 0)
&& GET_CODE (b) == LTU
- && GET_CODE (opb1) == CONST_INT)
+ && CONST_INT_P (opb1)
+ && rtx_equal_p (op0, opb0))
return INTVAL (opb1) < 0;
return false;
@@ -1580,7 +1649,7 @@ canon_condition (rtx cond)
mode = GET_MODE (op1);
gcc_assert (mode != VOIDmode);
- if (GET_CODE (op1) == CONST_INT
+ if (CONST_INT_P (op1)
&& GET_MODE_CLASS (mode) != MODE_CC
&& GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT)
{
@@ -1637,15 +1706,22 @@ simplify_using_condition (rtx cond, rtx *expr, regset altered)
{
rtx rev, reve, exp = *expr;
- if (!COMPARISON_P (exp))
- return;
-
/* If some register gets altered later, we do not really speak about its
value at the time of comparison. */
if (altered
&& for_each_rtx (&cond, altered_reg_used, altered))
return;
+ if (GET_CODE (cond) == EQ
+ && REG_P (XEXP (cond, 0)) && CONSTANT_P (XEXP (cond, 1)))
+ {
+ *expr = simplify_replace_rtx (*expr, XEXP (cond, 0), XEXP (cond, 1));
+ return;
+ }
+
+ if (!COMPARISON_P (exp))
+ return;
+
rev = reversed_condition (cond);
reve = reversed_condition (exp);
@@ -1662,7 +1738,6 @@ simplify_using_condition (rtx cond, rtx *expr, regset altered)
return;
}
-
if (rev && rtx_equal_p (exp, rev))
{
*expr = const0_rtx;
@@ -1674,7 +1749,7 @@ simplify_using_condition (rtx cond, rtx *expr, regset altered)
*expr = const_true_rtx;
return;
}
-
+
if (reve && implies_p (cond, reve))
{
*expr = const0_rtx;
@@ -1746,9 +1821,10 @@ eliminate_implied_conditions (enum rtx_code op, rtx *head, rtx tail)
static void
simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
{
- rtx head, tail, insn;
+ bool expression_valid;
+ rtx head, tail, insn, cond_list, last_valid_expr;
rtx neutral, aggr;
- regset altered;
+ regset altered, this_altered;
edge e;
if (!*expr)
@@ -1779,7 +1855,7 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
default:
gcc_unreachable ();
}
-
+
simplify_using_initial_values (loop, UNKNOWN, &head);
if (head == aggr)
{
@@ -1800,7 +1876,7 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
*expr = tail;
return;
}
-
+
XEXP (*expr, 0) = head;
XEXP (*expr, 1) = tail;
return;
@@ -1808,48 +1884,122 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
gcc_assert (op == UNKNOWN);
+ for (;;)
+ if (for_each_rtx (expr, replace_single_def_regs, expr) == 0)
+ break;
+ if (CONSTANT_P (*expr))
+ return;
+
e = loop_preheader_edge (loop);
if (e->src == ENTRY_BLOCK_PTR)
return;
altered = ALLOC_REG_SET (®_obstack);
+ this_altered = ALLOC_REG_SET (®_obstack);
+ expression_valid = true;
+ last_valid_expr = *expr;
+ cond_list = NULL_RTX;
while (1)
{
insn = BB_END (e->src);
if (any_condjump_p (insn))
{
rtx cond = get_condition (BB_END (e->src), NULL, false, true);
-
+
if (cond && (e->flags & EDGE_FALLTHRU))
cond = reversed_condition (cond);
if (cond)
{
+ rtx old = *expr;
simplify_using_condition (cond, expr, altered);
- if (CONSTANT_P (*expr))
+ if (old != *expr)
{
- FREE_REG_SET (altered);
- return;
+ rtx note;
+ if (CONSTANT_P (*expr))
+ goto out;
+ for (note = cond_list; note; note = XEXP (note, 1))
+ {
+ simplify_using_condition (XEXP (note, 0), expr, altered);
+ if (CONSTANT_P (*expr))
+ goto out;
+ }
}
+ cond_list = alloc_EXPR_LIST (0, cond, cond_list);
}
}
FOR_BB_INSNS_REVERSE (e->src, insn)
{
+ rtx src, dest;
+ rtx old = *expr;
+
if (!INSN_P (insn))
continue;
-
- simplify_using_assignment (insn, expr, altered);
- if (CONSTANT_P (*expr))
+
+ CLEAR_REG_SET (this_altered);
+ note_stores (PATTERN (insn), mark_altered, this_altered);
+ if (CALL_P (insn))
{
- FREE_REG_SET (altered);
- return;
+ int i;
+
+ /* Kill all call clobbered registers. */
+ for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+ if (TEST_HARD_REG_BIT (regs_invalidated_by_call, i))
+ SET_REGNO_REG_SET (this_altered, i);
}
- if (for_each_rtx (expr, altered_reg_used, altered))
+
+ if (suitable_set_for_replacement (insn, &dest, &src))
{
- FREE_REG_SET (altered);
- return;
+ rtx *pnote, *pnote_next;
+
+ replace_in_expr (expr, dest, src);
+ if (CONSTANT_P (*expr))
+ goto out;
+
+ for (pnote = &cond_list; *pnote; pnote = pnote_next)
+ {
+ rtx note = *pnote;
+ rtx old_cond = XEXP (note, 0);
+
+ pnote_next = &XEXP (note, 1);
+ replace_in_expr (&XEXP (note, 0), dest, src);
+
+ /* We can no longer use a condition that has been simplified
+ to a constant, and simplify_using_condition will abort if
+ we try. */
+ if (CONSTANT_P (XEXP (note, 0)))
+ {
+ *pnote = *pnote_next;
+ pnote_next = pnote;
+ free_EXPR_LIST_node (note);
+ }
+ /* Retry simplifications with this condition if either the
+ expression or the condition changed. */
+ else if (old_cond != XEXP (note, 0) || old != *expr)
+ simplify_using_condition (XEXP (note, 0), expr, altered);
+ }
}
+ else
+ /* If we did not use this insn to make a replacement, any overlap
+ between stores in this insn and our expression will cause the
+ expression to become invalid. */
+ if (for_each_rtx (expr, altered_reg_used, this_altered))
+ goto out;
+
+ if (CONSTANT_P (*expr))
+ goto out;
+
+ IOR_REG_SET (altered, this_altered);
+
+ /* If the expression now contains regs that have been altered, we
+ can't return it to the caller. However, it is still valid for
+ further simplification, so keep searching to see if we can
+ eventually turn it into a constant. */
+ if (for_each_rtx (expr, altered_reg_used, altered))
+ expression_valid = false;
+ if (expression_valid)
+ last_valid_expr = *expr;
}
if (!single_pred_p (e->src)
@@ -1858,7 +2008,12 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
e = single_pred_edge (e->src);
}
+ out:
+ free_EXPR_LIST_list (&cond_list);
+ if (!CONSTANT_P (*expr))
+ *expr = last_valid_expr;
FREE_REG_SET (altered);
+ FREE_REG_SET (this_altered);
}
/* Transforms invariant IV into MODE. Adds assumptions based on the fact
@@ -1982,7 +2137,7 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
and iv0 and iv1 are both ivs iterating in SI mode, but calculated
in different modes. This does not seem impossible to handle, but
it hardly ever occurs in practice.
-
+
The only exception is the case when one of operands is invariant.
For example pentium 3 generates comparisons like
(lt (subreg:HI (reg:SI)) 100). Here we assign HImode to 100, but we
@@ -2035,17 +2190,20 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
return true;
}
-/* Tries to estimate the maximum number of iterations. */
+/* Tries to estimate the maximum number of iterations in LOOP, and store the
+ result in DESC. This function is called from iv_number_of_iterations with
+ a number of fields in DESC already filled in. OLD_NITER is the original
+ expression for the number of iterations, before we tried to simplify it. */
static unsigned HOST_WIDEST_INT
-determine_max_iter (struct loop *loop, struct niter_desc *desc)
+determine_max_iter (struct loop *loop, struct niter_desc *desc, rtx old_niter)
{
rtx niter = desc->niter_expr;
rtx mmin, mmax, cmp;
unsigned HOST_WIDEST_INT nmax, inc;
if (GET_CODE (niter) == AND
- && GET_CODE (XEXP (niter, 0)) == CONST_INT)
+ && CONST_INT_P (XEXP (niter, 0)))
{
nmax = INTVAL (XEXP (niter, 0));
if (!(nmax & (nmax + 1)))
@@ -2060,7 +2218,7 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc)
if (GET_CODE (niter) == UDIV)
{
- if (GET_CODE (XEXP (niter, 1)) != CONST_INT)
+ if (!CONST_INT_P (XEXP (niter, 1)))
{
desc->niter_max = nmax;
return nmax;
@@ -2073,7 +2231,8 @@ determine_max_iter (struct loop *loop, struct niter_desc *desc)
/* We could use a binary search here, but for now improving the upper
bound by just one eliminates one important corner case. */
- cmp = gen_rtx_fmt_ee (desc->signed_p ? LT : LTU, VOIDmode, niter, mmax);
+ cmp = simplify_gen_relational (desc->signed_p ? LT : LTU, VOIDmode,
+ desc->mode, old_niter, mmax);
simplify_using_initial_values (loop, UNKNOWN, &cmp);
if (cmp == const_true_rtx)
{
@@ -2140,7 +2299,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
goto fail;
if (iv0.extend_mode == VOIDmode)
iv0.mode = iv0.extend_mode = mode;
-
+
op1 = XEXP (condition, 1);
if (!iv_analyze (insn, op1, &iv1))
goto fail;
@@ -2187,7 +2346,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
mode_mmin = lowpart_subreg (mode, mmin, comp_mode);
mode_mmax = lowpart_subreg (mode, mmax, comp_mode);
- if (GET_CODE (iv0.step) != CONST_INT || GET_CODE (iv1.step) != CONST_INT)
+ if (!CONST_INT_P (iv0.step) || !CONST_INT_P (iv1.step))
goto fail;
/* We can take care of the case of two induction variables chasing each other
@@ -2318,7 +2477,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
may_xform = const0_rtx;
may_not_xform = const_true_rtx;
- if (GET_CODE (delta) == CONST_INT)
+ if (CONST_INT_P (delta))
{
if (was_sharp && INTVAL (delta) == INTVAL (step) - 1)
{
@@ -2381,11 +2540,11 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
number of iterations in this step, so record the information
here. */
inc = INTVAL (iv0.step) - INTVAL (iv1.step);
- if (GET_CODE (iv1.base) == CONST_INT)
+ if (CONST_INT_P (iv1.base))
up = INTVAL (iv1.base);
else
up = INTVAL (mode_mmax) - inc;
- down = INTVAL (GET_CODE (iv0.base) == CONST_INT
+ down = INTVAL (CONST_INT_P (iv0.base)
? iv0.base
: mode_mmin);
desc->niter_max = (up - down) / inc + 1;
@@ -2594,7 +2753,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
&& XEXP (desc->noloop_assumptions, 0) == const_true_rtx)
goto zero_iter;
- if (GET_CODE (desc->niter_expr) == CONST_INT)
+ if (CONST_INT_P (desc->niter_expr))
{
unsigned HOST_WIDEST_INT val = INTVAL (desc->niter_expr);
@@ -2604,7 +2763,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
else
{
if (!desc->niter_max)
- desc->niter_max = determine_max_iter (loop, desc);
+ desc->niter_max = determine_max_iter (loop, desc, old_niter);
/* simplify_using_initial_values does a copy propagation on the registers
in the expression for the number of iterations. This prolongs life
@@ -2708,7 +2867,7 @@ find_simple_exit (struct loop *loop, struct niter_desc *desc)
{
if (flow_bb_inside_loop_p (loop, e->dest))
continue;
-
+
check_simple_exit (loop, e, &act);
if (!act.simple_p)
continue;
@@ -2727,7 +2886,7 @@ find_simple_exit (struct loop *loop, struct niter_desc *desc)
if (act.infinite && !desc->infinite)
continue;
}
-
+
*desc = act;
}
}
@@ -2785,22 +2944,24 @@ get_simple_loop_desc (struct loop *loop)
if (desc)
return desc;
- desc = XNEW (struct niter_desc);
+ /* At least desc->infinite is not always initialized by
+ find_simple_loop_exit. */
+ desc = XCNEW (struct niter_desc);
iv_analysis_loop_init (loop);
find_simple_exit (loop, desc);
loop->aux = desc;
if (desc->simple_p && (desc->assumptions || desc->infinite))
{
- const char *wording;
+ const char *wording;
- /* Assume that no overflow happens and that the loop is finite.
+ /* Assume that no overflow happens and that the loop is finite.
We already warned at the tree level if we ran optimizations there. */
if (!flag_tree_loop_optimize && warn_unsafe_loop_optimizations)
{
if (desc->infinite)
{
- wording =
+ wording =
flag_unsafe_loop_optimizations
? N_("assuming that the loop is not infinite")
: N_("cannot optimize possibly infinite loops");
@@ -2809,7 +2970,7 @@ get_simple_loop_desc (struct loop *loop)
}
if (desc->assumptions)
{
- wording =
+ wording =
flag_unsafe_loop_optimizations
? N_("assuming that the loop counter does not overflow")
: N_("cannot optimize loop, the loop counter may overflow");