X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=blobdiff_plain;f=gcc%2Floop-iv.c;h=af25d02ed61d0fefba8f4770b059267f9a363f3f;hp=e234fd93b7993283edaa06a167021e60ed36fe3f;hb=fef144401409894f6457aae538e0b4c5e3a72c4c;hpb=4c36ffe68d981c213d168cf07f42dcc558bc7f1b
diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index e234fd93b79..af25d02ed61 100644
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -1,11 +1,12 @@
/* Rtl-level induction variable analysis.
- Copyright (C) 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009
+ 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
@@ -14,18 +15,18 @@ 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
@@ -45,8 +46,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
iv_analyze_expr (insn, rhs, mode, iv): Stores to IV the description of iv
corresponding to expression EXPR evaluated at INSN. All registers used bu
EXPR must also be used in INSN.
- iv_current_loop_df (): Returns the dataflow object for the current loop used
- by iv analysis. */
+*/
#include "config.h"
#include "system.h"
@@ -92,29 +92,25 @@ struct biv_entry
struct rtx_iv iv; /* Value of the biv. */
};
+static bool clean_slate = true;
+
+static unsigned int iv_ref_table_size = 0;
+
+/* Table of rtx_ivs indexed by the df_ref uid field. */
+static struct rtx_iv ** iv_ref_table;
+
/* Induction variable stored at the reference. */
-#define DF_REF_IV(REF) ((struct rtx_iv *) DF_REF_DATA (REF))
-#define DF_REF_IV_SET(REF, IV) DF_REF_DATA (REF) = (IV)
+#define DF_REF_IV(REF) iv_ref_table[DF_REF_ID(REF)]
+#define DF_REF_IV_SET(REF, IV) iv_ref_table[DF_REF_ID(REF)] = (IV)
/* The current loop. */
static struct loop *current_loop;
-/* Dataflow information for the current loop. */
-
-static struct df *df = NULL;
-
/* Bivs of the current loop. */
static htab_t bivs;
-/* Return the dataflow object for the current loop. */
-struct df *
-iv_current_loop_df (void)
-{
- return df;
-}
-
static bool iv_analyze_op (rtx, rtx, struct rtx_iv *);
/* Dumps information about IV to FILE. */
@@ -172,6 +168,20 @@ lowpart_subreg (enum machine_mode outer_mode, rtx expr,
subreg_lowpart_offset (outer_mode, inner_mode));
}
+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 = 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;
+ }
+}
+
+
/* Checks whether REG is a well-behaved register. */
static bool
@@ -204,18 +214,18 @@ simple_reg_p (rtx reg)
static void
clear_iv_info (void)
{
- unsigned i, n_defs = DF_DEFS_SIZE (df);
+ unsigned i, n_defs = DF_DEFS_TABLE_SIZE ();
struct rtx_iv *iv;
- struct df_ref *def;
+ check_iv_ref_table_size ();
for (i = 0; i < n_defs; i++)
{
- def = DF_DEFS_GET (df, i);
- iv = DF_REF_IV (def);
- if (!iv)
- continue;
- free (iv);
- DF_REF_IV_SET (def, NULL);
+ iv = iv_ref_table[i];
+ if (iv)
+ {
+ free (iv);
+ iv_ref_table[i] = NULL;
+ }
}
htab_empty (bivs);
@@ -234,7 +244,7 @@ biv_hash (const void *b)
static int
biv_eq (const void *b, const void *r)
{
- return ((const struct biv_entry *) b)->regno == REGNO ((rtx) r);
+ return ((const struct biv_entry *) b)->regno == REGNO ((const_rtx) r);
}
/* Prepare the data for an induction variable analysis of a LOOP. */
@@ -245,16 +255,15 @@ iv_analysis_loop_init (struct loop *loop)
basic_block *body = get_loop_body_in_dom_order (loop), bb;
bitmap blocks = BITMAP_ALLOC (NULL);
unsigned i;
- bool first_time = (df == NULL);
current_loop = loop;
/* Clear the information from the analysis of the previous loop. */
- if (first_time)
+ if (clean_slate)
{
- df = df_init (DF_HARD_REGS | DF_EQUIV_NOTES);
- df_chain_add_problem (df, DF_UD_CHAIN);
+ df_set_flags (DF_EQ_NOTES + DF_DEFER_INSN_RESCAN);
bivs = htab_create (10, biv_hash, biv_eq, free);
+ clean_slate = false;
}
else
clear_iv_info ();
@@ -264,8 +273,18 @@ iv_analysis_loop_init (struct loop *loop)
bb = body[i];
bitmap_set_bit (blocks, bb->index);
}
- df_set_blocks (df, blocks);
- df_analyze (df);
+ /* Get rid of the ud chains before processing the rescans. Then add
+ the problem back. */
+ 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_region (dump_file);
+
+ check_iv_ref_table_size ();
BITMAP_FREE (blocks);
free (body);
}
@@ -276,16 +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_reg_info *reg_info = DF_REG_DEF_GET (df, regno);
- struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (df, current_loop->latch);
+ struct df_rd_bb_info *bb_info = DF_RD_BB_INFO (current_loop->latch);
- for (adef = reg_info->reg_chain; 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. */
@@ -305,9 +324,9 @@ 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;
@@ -319,7 +338,7 @@ iv_get_reaching_def (rtx insn, rtx reg, struct df_ref **def)
reg = SUBREG_REG (reg);
gcc_assert (REG_P (reg));
- use = df_find_use (df, insn, reg);
+ use = df_find_use (insn, reg);
gcc_assert (use != NULL);
if (!DF_REF_CHAIN (use))
@@ -330,12 +349,17 @@ iv_get_reaching_def (rtx insn, rtx reg, struct df_ref **def)
return GRD_INVALID;
adef = DF_REF_CHAIN (use)->ref;
+
+ /* We do not handle setting only part of the register. */
+ if (DF_REF_FLAGS (adef) & DF_REF_READ_WRITE)
+ return GRD_INVALID;
+
def_insn = DF_REF_INSN (adef);
def_bb = DF_REF_BB (adef);
use_bb = BLOCK_FOR_INSN (insn);
if (use_bb == def_bb)
- dom_p = (DF_INSN_LUID (df, def_insn) < DF_INSN_LUID (df, insn));
+ dom_p = (DF_INSN_LUID (def_insn) < DF_INSN_LUID (insn));
else
dom_p = dominated_by_p (CDI_DOMINATORS, use_bb, def_bb);
@@ -594,7 +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)
@@ -603,7 +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);
@@ -761,7 +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)
{
@@ -781,11 +805,12 @@ 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);
*recorded_iv = *iv;
+ check_iv_ref_table_size ();
DF_REF_IV_SET (def, recorded_iv);
}
@@ -795,7 +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;
@@ -825,7 +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)
{
@@ -1018,7 +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);
@@ -1026,12 +1052,13 @@ iv_analyze_def (struct df_ref *def, struct rtx_iv *iv)
if (dump_file)
{
- fprintf (dump_file, "Analysing def of ");
+ fprintf (dump_file, "Analyzing def of ");
print_rtl (dump_file, reg);
fprintf (dump_file, " in insn ");
print_rtl_single (dump_file, insn);
}
-
+
+ check_iv_ref_table_size ();
if (DF_REF_IV (def))
{
if (dump_file)
@@ -1044,10 +1071,17 @@ iv_analyze_def (struct df_ref *def, struct rtx_iv *iv)
iv->base = NULL_RTX;
iv->step = NULL_RTX;
+ if (!REG_P (reg))
+ return false;
+
set = single_set (insn);
- if (!set || SET_DEST (set) != reg)
+ if (!set)
return false;
+ if (!REG_P (SET_DEST (set)))
+ return false;
+
+ gcc_assert (SET_DEST (set) == reg);
rhs = find_reg_equal_equiv_note (insn);
if (rhs)
rhs = XEXP (rhs, 0);
@@ -1075,18 +1109,18 @@ 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)
{
- fprintf (dump_file, "Analysing operand ");
+ fprintf (dump_file, "Analyzing operand ");
print_rtl (dump_file, op);
fprintf (dump_file, " of insn ");
print_rtl_single (dump_file, insn);
}
- if (CONSTANT_P (op))
+ if (function_invariant_p (op))
res = GRD_INVARIANT;
else if (GET_CODE (op) == SUBREG)
{
@@ -1146,7 +1180,7 @@ iv_analyze (rtx insn, rtx val, struct rtx_iv *iv)
else
reg = val;
- while (!df_find_use (df, insn, reg))
+ while (!df_find_use (insn, reg))
insn = NEXT_INSN (insn);
}
@@ -1158,9 +1192,9 @@ 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 (df, insn, def);
+ adef = df_find_def (insn, def);
if (!adef)
return false;
@@ -1175,12 +1209,12 @@ 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;
- def = df_find_def (df, insn, reg);
+ def = df_find_def (insn, reg);
gcc_assert (def != NULL);
if (!latch_dominating_def (reg, &last_def))
return false;
@@ -1232,12 +1266,15 @@ get_iv_value (struct rtx_iv *iv, rtx iteration)
void
iv_analysis_done (void)
{
- if (df)
+ if (!clean_slate)
{
clear_iv_info ();
- df_finish (df);
- df = NULL;
+ clean_slate = true;
+ df_finish_pass (true);
htab_delete (bivs);
+ free (iv_ref_table);
+ iv_ref_table = NULL;
+ iv_ref_table_size = 0;
bivs = NULL;
}
}
@@ -1261,71 +1298,6 @@ inverse (unsigned HOST_WIDEST_INT x, int mod)
return rslt;
}
-/* Tries to estimate the maximum number of iterations. */
-
-static unsigned HOST_WIDEST_INT
-determine_max_iter (struct niter_desc *desc)
-{
- rtx niter = desc->niter_expr;
- rtx mmin, mmax, left, right;
- unsigned HOST_WIDEST_INT nmax, inc;
-
- if (GET_CODE (niter) == AND
- && GET_CODE (XEXP (niter, 0)) == CONST_INT)
- {
- nmax = INTVAL (XEXP (niter, 0));
- if (!(nmax & (nmax + 1)))
- {
- desc->niter_max = nmax;
- return nmax;
- }
- }
-
- get_mode_bounds (desc->mode, desc->signed_p, desc->mode, &mmin, &mmax);
- nmax = INTVAL (mmax) - INTVAL (mmin);
-
- if (GET_CODE (niter) == UDIV)
- {
- if (GET_CODE (XEXP (niter, 1)) != CONST_INT)
- {
- desc->niter_max = nmax;
- return nmax;
- }
- inc = INTVAL (XEXP (niter, 1));
- niter = XEXP (niter, 0);
- }
- else
- inc = 1;
-
- if (GET_CODE (niter) == PLUS)
- {
- left = XEXP (niter, 0);
- right = XEXP (niter, 0);
-
- if (GET_CODE (right) == CONST_INT)
- right = GEN_INT (-INTVAL (right));
- }
- else if (GET_CODE (niter) == MINUS)
- {
- left = XEXP (niter, 0);
- right = XEXP (niter, 0);
- }
- else
- {
- left = niter;
- right = mmin;
- }
-
- if (GET_CODE (left) == CONST_INT)
- mmax = left;
- if (GET_CODE (right) == CONST_INT)
- mmin = right;
- nmax = INTVAL (mmax) - INTVAL (mmin);
-
- desc->niter_max = nmax / inc;
- return nmax / inc;
-}
-
/* Checks whether register *REG is in set ALT. Callback for for_each_rtx. */
static int
@@ -1334,20 +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. */
@@ -1357,62 +1329,114 @@ simple_rhs_p (rtx rhs)
{
rtx op0, op1;
- if (CONSTANT_P (rhs)
- || REG_P (rhs))
+ if (function_invariant_p (rhs)
+ || (REG_P (rhs) && !HARD_REGISTER_P (rhs)))
return true;
switch (GET_CODE (rhs))
{
case PLUS:
case MINUS:
+ case AND:
op0 = XEXP (rhs, 0);
op1 = XEXP (rhs, 1);
- /* Allow reg + const sets only. */
- if (REG_P (op0) && CONSTANT_P (op1))
- return true;
- if (REG_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));
+
+ if (note && function_invariant_p (XEXP (note, 0)))
+ {
+ src = XEXP (note, 0);
+ break;
+ }
+ src = SET_SRC (set);
- /* 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 (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)
@@ -1421,12 +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. */
@@ -1457,14 +1494,34 @@ implies_p (rtx a, rtx b)
}
}
+ if (b == const_true_rtx)
+ return true;
+
+ if ((GET_RTX_CLASS (GET_CODE (a)) != RTX_COMM_COMPARE
+ && GET_RTX_CLASS (GET_CODE (a)) != RTX_COMPARE)
+ || (GET_RTX_CLASS (GET_CODE (b)) != RTX_COMM_COMPARE
+ && GET_RTX_CLASS (GET_CODE (b)) != RTX_COMPARE))
+ return false;
+
+ op0 = XEXP (a, 0);
+ op1 = XEXP (a, 1);
+ opb0 = XEXP (b, 0);
+ opb1 = XEXP (b, 1);
+
+ mode = GET_MODE (op0);
+ if (mode != GET_MODE (opb0))
+ mode = VOIDmode;
+ else if (mode == VOIDmode)
+ {
+ mode = GET_MODE (op1);
+ if (mode != GET_MODE (opb1))
+ mode = VOIDmode;
+ }
+
/* A < B implies A + 1 <= B. */
if ((GET_CODE (a) == GT || GET_CODE (a) == LT)
&& (GET_CODE (b) == GE || GET_CODE (b) == LE))
{
- op0 = XEXP (a, 0);
- op1 = XEXP (a, 1);
- opb0 = XEXP (b, 0);
- opb1 = XEXP (b, 1);
if (GET_CODE (a) == GT)
{
@@ -1480,22 +1537,83 @@ implies_p (rtx a, rtx b)
opb1 = r;
}
- mode = GET_MODE (op0);
- if (mode != GET_MODE (opb0))
- mode = VOIDmode;
- else if (mode == VOIDmode)
- {
- mode = GET_MODE (op1);
- if (mode != GET_MODE (opb1))
- mode = VOIDmode;
- }
-
- if (mode != VOIDmode
+ if (SCALAR_INT_MODE_P (mode)
&& rtx_equal_p (op1, opb1)
&& simplify_gen_binary (MINUS, mode, opb0, op0) == const1_rtx)
return true;
+ return false;
}
+ /* A < B or A > B imply A != B. TODO: Likewise
+ A + n < B implies A != B + n if neither wraps. */
+ if (GET_CODE (b) == NE
+ && (GET_CODE (a) == GT || GET_CODE (a) == GTU
+ || GET_CODE (a) == LT || GET_CODE (a) == LTU))
+ {
+ if (rtx_equal_p (op0, opb0)
+ && rtx_equal_p (op1, opb1))
+ return true;
+ }
+
+ /* For unsigned comparisons, A != 0 implies A > 0 and A >= 1. */
+ if (GET_CODE (a) == NE
+ && op1 == const0_rtx)
+ {
+ if ((GET_CODE (b) == GTU
+ && opb1 == const0_rtx)
+ || (GET_CODE (b) == GEU
+ && opb1 == const1_rtx))
+ return rtx_equal_p (op0, opb0);
+ }
+
+ /* A != N is equivalent to A - (N + 1) 0. */
+ if (GET_CODE (a) == NE
+ && CONST_INT_P (op1))
+ {
+ if (GET_CODE (b) == GTU
+ && GET_CODE (opb0) == PLUS
+ && opb1 == const0_rtx
+ && 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)))
+ && rtx_equal_p (XEXP (opb0, 0), op0))
+ return INTVAL (op1) == -INTVAL (XEXP (opb0, 1));
+ if (GET_CODE (b) == GEU
+ && GET_CODE (opb0) == PLUS
+ && opb1 == const1_rtx
+ && 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)))
+ && rtx_equal_p (XEXP (opb0, 0), op0))
+ return INTVAL (op1) == -INTVAL (XEXP (opb0, 1));
+ }
+
+ /* A >s X, where X is positive, implies A = 0)
+ && GET_CODE (b) == LTU
+ && CONST_INT_P (opb1)
+ && rtx_equal_p (op0, opb0))
+ return INTVAL (opb1) < 0;
+
return false;
}
@@ -1531,7 +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)
{
@@ -1588,15 +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);
@@ -1613,7 +1738,6 @@ simplify_using_condition (rtx cond, rtx *expr, regset altered)
return;
}
-
if (rev && rtx_equal_p (exp, rev))
{
*expr = const0_rtx;
@@ -1697,9 +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)
@@ -1759,43 +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))
+ {
+ 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 (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)
@@ -1804,7 +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
@@ -1981,6 +2190,61 @@ canonicalize_iv_subregs (struct rtx_iv *iv0, struct rtx_iv *iv1,
return true;
}
+/* 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, rtx old_niter)
+{
+ rtx niter = desc->niter_expr;
+ rtx mmin, mmax, cmp;
+ unsigned HOST_WIDEST_INT nmax, inc;
+
+ if (GET_CODE (niter) == AND
+ && CONST_INT_P (XEXP (niter, 0)))
+ {
+ nmax = INTVAL (XEXP (niter, 0));
+ if (!(nmax & (nmax + 1)))
+ {
+ desc->niter_max = nmax;
+ return nmax;
+ }
+ }
+
+ get_mode_bounds (desc->mode, desc->signed_p, desc->mode, &mmin, &mmax);
+ nmax = INTVAL (mmax) - INTVAL (mmin);
+
+ if (GET_CODE (niter) == UDIV)
+ {
+ if (!CONST_INT_P (XEXP (niter, 1)))
+ {
+ desc->niter_max = nmax;
+ return nmax;
+ }
+ inc = INTVAL (XEXP (niter, 1));
+ niter = XEXP (niter, 0);
+ }
+ else
+ inc = 1;
+
+ /* We could use a binary search here, but for now improving the upper
+ bound by just one eliminates one important corner case. */
+ 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)
+ {
+ nmax--;
+
+ if (dump_file)
+ fprintf (dump_file, ";; improved upper bound by one.\n");
+ }
+ desc->niter_max = nmax / inc;
+ return nmax / inc;
+}
+
/* Computes number of iterations of the CONDITION in INSN in LOOP and stores
the result into DESC. Very similar to determine_number_of_iterations
(basically its rtl version), complicated by things like subregs. */
@@ -2082,7 +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
@@ -2213,7 +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)
{
@@ -2276,11 +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;
@@ -2489,7 +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);
@@ -2499,7 +2763,7 @@ iv_number_of_iterations (struct loop *loop, rtx insn, rtx condition,
else
{
if (!desc->niter_max)
- desc->niter_max = determine_max_iter (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
@@ -2680,7 +2944,9 @@ 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;