/* RTL-based forward propagation pass for GNU compiler.
- Copyright (C) 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
Contributed by Paolo Bonzini and Steven Bosscher.
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 later
+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
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
+<http://www.gnu.org/licenses/>. */
#include "config.h"
#include "system.h"
#include "target.h"
#include "cfgloop.h"
#include "tree-pass.h"
+#include "domwalk.h"
/* This pass does simple forward propagation and simplification when an
(set (reg:QI 121) (subreg:QI (reg:SI 119) 0))
(set (reg:SI 122) (plus:SI (reg:SI 118) (reg:SI 119)))
- where the first two insns are now dead. */
+ where the first two insns are now dead.
+
+ We used to use reaching definitions to find which uses have a
+ single reaching definition (sounds obvious...), but this is too
+ complex a problem in nasty testcases like PR33928. Now we use the
+ multiple definitions problem in df-problems.c. The similarity
+ between that problem and SSA form creation is taken further, in
+ that fwprop does a dominator walk to create its chains; however,
+ instead of creating a PHI function where multiple definitions meet
+ I just punt and record only singleton use-def chains, which is
+ all that is needed by fwprop. */
static int num_changes;
+DEF_VEC_P(df_ref);
+DEF_VEC_ALLOC_P(df_ref,heap);
+VEC(df_ref,heap) *use_def_ref;
+VEC(df_ref,heap) *reg_defs;
+VEC(df_ref,heap) *reg_defs_stack;
+
+
+/* Return the only def in USE's use-def chain, or NULL if there is
+ more than one def in the chain. */
+
+static inline df_ref
+get_def_for_use (df_ref use)
+{
+ return VEC_index (df_ref, use_def_ref, DF_REF_ID (use));
+}
+
+
+/* Update the reg_defs vector with non-partial definitions in DEF_REC.
+ TOP_FLAG says which artificials uses should be used, when DEF_REC
+ is an artificial def vector. LOCAL_MD is modified as after a
+ df_md_simulate_* function; we do more or less the same processing
+ done there, so we do not use those functions. */
+
+#define DF_MD_GEN_FLAGS \
+ (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER)
+
+static void
+process_defs (bitmap local_md, df_ref *def_rec, int top_flag)
+{
+ df_ref def;
+ while ((def = *def_rec++) != NULL)
+ {
+ df_ref curr_def = VEC_index (df_ref, reg_defs, DF_REF_REGNO (def));
+ unsigned int dregno;
+
+ if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) != top_flag)
+ continue;
+
+ dregno = DF_REF_REGNO (def);
+ if (curr_def)
+ VEC_safe_push (df_ref, heap, reg_defs_stack, curr_def);
+ else
+ {
+ /* Do not store anything if "transitioning" from NULL to NULL. But
+ otherwise, push a special entry on the stack to tell the
+ leave_block callback that the entry in reg_defs was NULL. */
+ if (DF_REF_FLAGS (def) & DF_MD_GEN_FLAGS)
+ ;
+ else
+ VEC_safe_push (df_ref, heap, reg_defs_stack, def);
+ }
+
+ if (DF_REF_FLAGS (def) & DF_MD_GEN_FLAGS)
+ {
+ bitmap_set_bit (local_md, dregno);
+ VEC_replace (df_ref, reg_defs, dregno, NULL);
+ }
+ else
+ {
+ bitmap_clear_bit (local_md, dregno);
+ VEC_replace (df_ref, reg_defs, dregno, def);
+ }
+ }
+}
+
+
+/* Fill the use_def_ref vector with values for the uses in USE_REC,
+ taking reaching definitions info from LOCAL_MD and REG_DEFS.
+ TOP_FLAG says which artificials uses should be used, when USE_REC
+ is an artificial use vector. */
+
+static void
+process_uses (bitmap local_md, df_ref *use_rec, int top_flag)
+{
+ df_ref use;
+ while ((use = *use_rec++) != NULL)
+ if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == top_flag)
+ {
+ unsigned int uregno = DF_REF_REGNO (use);
+ if (VEC_index (df_ref, reg_defs, uregno)
+ && !bitmap_bit_p (local_md, uregno))
+ VEC_replace (df_ref, use_def_ref, DF_REF_ID (use),
+ VEC_index (df_ref, reg_defs, uregno));
+ }
+}
+
+
+static void
+single_def_use_enter_block (struct dom_walk_data *walk_data, basic_block bb)
+{
+ bitmap local_md = (bitmap) walk_data->global_data;
+ int bb_index = bb->index;
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+ rtx insn;
+
+ bitmap_copy (local_md, bb_info->in);
+
+ /* Push a marker for the leave_block callback. */
+ VEC_safe_push (df_ref, heap, reg_defs_stack, NULL);
+
+ process_uses (local_md, df_get_artificial_uses (bb_index), DF_REF_AT_TOP);
+ process_defs (local_md, df_get_artificial_defs (bb_index), DF_REF_AT_TOP);
+
+ FOR_BB_INSNS (bb, insn)
+ if (INSN_P (insn))
+ {
+ unsigned int uid = INSN_UID (insn);
+ process_uses (local_md, DF_INSN_UID_USES (uid), 0);
+ process_uses (local_md, DF_INSN_UID_EQ_USES (uid), 0);
+ process_defs (local_md, DF_INSN_UID_DEFS (uid), 0);
+ }
+
+ process_uses (local_md, df_get_artificial_uses (bb_index), 0);
+ process_defs (local_md, df_get_artificial_defs (bb_index), 0);
+}
+
+/* Pop the definitions created in this basic block when leaving its
+ dominated parts. */
+
+static void
+single_def_use_leave_block (struct dom_walk_data *walk_data ATTRIBUTE_UNUSED,
+ basic_block bb ATTRIBUTE_UNUSED)
+{
+ df_ref saved_def;
+ while ((saved_def = VEC_pop (df_ref, reg_defs_stack)) != NULL)
+ {
+ unsigned int dregno = DF_REF_REGNO (saved_def);
+
+ /* See also process_defs. */
+ if (saved_def == VEC_index (df_ref, reg_defs, dregno))
+ VEC_replace (df_ref, reg_defs, dregno, NULL);
+ else
+ VEC_replace (df_ref, reg_defs, dregno, saved_def);
+ }
+}
+
+
+/* Build a vector holding the reaching definitions of uses reached by a
+ single dominating definition. */
+
+static void
+build_single_def_use_links (void)
+{
+ struct dom_walk_data walk_data;
+ bitmap local_md;
+
+ /* We use the multiple definitions problem to compute our restricted
+ use-def chains. */
+ df_set_flags (DF_EQ_NOTES);
+ df_md_add_problem ();
+ df_analyze ();
+ df_maybe_reorganize_use_refs (DF_REF_ORDER_BY_INSN_WITH_NOTES);
+
+ use_def_ref = VEC_alloc (df_ref, heap, DF_USES_TABLE_SIZE ());
+ VEC_safe_grow_cleared (df_ref, heap, use_def_ref, DF_USES_TABLE_SIZE ());
+
+ reg_defs = VEC_alloc (df_ref, heap, max_reg_num ());
+ VEC_safe_grow_cleared (df_ref, heap, reg_defs, max_reg_num ());
+
+ reg_defs_stack = VEC_alloc (df_ref, heap, n_basic_blocks * 10);
+ local_md = BITMAP_ALLOC (NULL);
+
+ /* Walk the dominator tree looking for single reaching definitions
+ dominating the uses. This is similar to how SSA form is built. */
+ walk_data.dom_direction = CDI_DOMINATORS;
+ walk_data.initialize_block_local_data = NULL;
+ walk_data.before_dom_children = single_def_use_enter_block;
+ walk_data.after_dom_children = single_def_use_leave_block;
+ walk_data.global_data = local_md;
+
+ init_walk_dominator_tree (&walk_data);
+ walk_dominator_tree (&walk_data, ENTRY_BLOCK_PTR);
+ fini_walk_dominator_tree (&walk_data);
+
+ BITMAP_FREE (local_md);
+ VEC_free (df_ref, heap, reg_defs);
+ VEC_free (df_ref, heap, reg_defs_stack);
+}
+
\f
/* Do not try to replace constant addresses or addresses of local and
argument slots. These MEM expressions are made only once and inserted
switch (GET_CODE (x))
{
case ASHIFT:
- if (GET_CODE (XEXP (x, 1)) == CONST_INT
+ if (CONST_INT_P (XEXP (x, 1))
&& INTVAL (XEXP (x, 1)) < GET_MODE_BITSIZE (GET_MODE (x))
&& INTVAL (XEXP (x, 1)) >= 0)
{
for a memory access in the given MODE. */
static bool
-should_replace_address (rtx old, rtx new, enum machine_mode mode)
+should_replace_address (rtx old_rtx, rtx new_rtx, enum machine_mode mode,
+ bool speed)
{
int gain;
- if (rtx_equal_p (old, new) || !memory_address_p (mode, new))
+ if (rtx_equal_p (old_rtx, new_rtx) || !memory_address_p (mode, new_rtx))
return false;
/* Copy propagation is always ok. */
- if (REG_P (old) && REG_P (new))
+ if (REG_P (old_rtx) && REG_P (new_rtx))
return true;
/* Prefer the new address if it is less expensive. */
- gain = address_cost (old, mode) - address_cost (new, mode);
+ gain = address_cost (old_rtx, mode, speed) - address_cost (new_rtx, mode, speed);
/* If the addresses have equivalent cost, prefer the new address
if it has the highest `rtx_cost'. That has the potential of
eliminating the most insns without additional costs, and it
is the same that cse.c used to do. */
if (gain == 0)
- gain = rtx_cost (new, SET) - rtx_cost (old, SET);
+ gain = rtx_cost (new_rtx, SET, speed) - rtx_cost (old_rtx, SET, speed);
return (gain > 0);
}
+
+/* Flags for the last parameter of propagate_rtx_1. */
+
+enum {
+ /* If PR_CAN_APPEAR is true, propagate_rtx_1 always returns true;
+ if it is false, propagate_rtx_1 returns false if, for at least
+ one occurrence OLD, it failed to collapse the result to a constant.
+ For example, (mult:M (reg:M A) (minus:M (reg:M B) (reg:M A))) may
+ collapse to zero if replacing (reg:M B) with (reg:M A).
+
+ PR_CAN_APPEAR is disregarded inside MEMs: in that case,
+ propagate_rtx_1 just tries to make cheaper and valid memory
+ addresses. */
+ PR_CAN_APPEAR = 1,
+
+ /* If PR_HANDLE_MEM is not set, propagate_rtx_1 won't attempt any replacement
+ outside memory addresses. This is needed because propagate_rtx_1 does
+ not do any analysis on memory; thus it is very conservative and in general
+ it will fail if non-read-only MEMs are found in the source expression.
+
+ PR_HANDLE_MEM is set when the source of the propagation was not
+ another MEM. Then, it is safe not to treat non-read-only MEMs as
+ ``opaque'' objects. */
+ PR_HANDLE_MEM = 2,
+
+ /* Set when costs should be optimized for speed. */
+ PR_OPTIMIZE_FOR_SPEED = 4
+};
+
+
/* Replace all occurrences of OLD in *PX with NEW and try to simplify the
resulting expression. Replace *PX with a new RTL expression if an
occurrence of OLD was found.
- If CAN_APPEAR is true, we always return true; if it is false, we
- can return false if, for at least one occurrence OLD, we failed to
- collapse the result to a constant. For example, (mult:M (reg:M A)
- (minus:M (reg:M B) (reg:M A))) may collapse to zero if replacing
- (reg:M B) with (reg:M A).
-
- CAN_APPEAR is disregarded inside MEMs: in that case, we always return
- true if the simplification is a cheaper and valid memory address.
-
This is only a wrapper around simplify-rtx.c: do not add any pattern
matching code here. (The sole exception is the handling of LO_SUM, but
that is because there is no simplify_gen_* function for LO_SUM). */
static bool
-propagate_rtx_1 (rtx *px, rtx old, rtx new, bool can_appear)
+propagate_rtx_1 (rtx *px, rtx old_rtx, rtx new_rtx, int flags)
{
rtx x = *px, tem = NULL_RTX, op0, op1, op2;
enum rtx_code code = GET_CODE (x);
enum machine_mode mode = GET_MODE (x);
enum machine_mode op_mode;
+ bool can_appear = (flags & PR_CAN_APPEAR) != 0;
bool valid_ops = true;
- /* If X is OLD_RTX, return NEW_RTX. Otherwise, if this is an expression,
- try to build a new expression from recursive substitution. */
+ if (!(flags & PR_HANDLE_MEM) && MEM_P (x) && !MEM_READONLY_P (x))
+ {
+ /* If unsafe, change MEMs to CLOBBERs or SCRATCHes (to preserve whether
+ they have side effects or not). */
+ *px = (side_effects_p (x)
+ ? gen_rtx_CLOBBER (GET_MODE (x), const0_rtx)
+ : gen_rtx_SCRATCH (GET_MODE (x)));
+ return false;
+ }
- if (x == old)
+ /* If X is OLD_RTX, return NEW_RTX. But not if replacing only within an
+ address, and we are *not* inside one. */
+ if (x == old_rtx)
{
- *px = new;
+ *px = new_rtx;
return can_appear;
}
+ /* If this is an expression, try recursive substitution. */
switch (GET_RTX_CLASS (code))
{
case RTX_UNARY:
op0 = XEXP (x, 0);
op_mode = GET_MODE (op0);
- valid_ops &= propagate_rtx_1 (&op0, old, new, can_appear);
+ valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0))
return true;
tem = simplify_gen_unary (code, mode, op0, op_mode);
case RTX_COMM_ARITH:
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
- valid_ops &= propagate_rtx_1 (&op0, old, new, can_appear);
- valid_ops &= propagate_rtx_1 (&op1, old, new, can_appear);
+ valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
+ valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
tem = simplify_gen_binary (code, mode, op0, op1);
op0 = XEXP (x, 0);
op1 = XEXP (x, 1);
op_mode = GET_MODE (op0) != VOIDmode ? GET_MODE (op0) : GET_MODE (op1);
- valid_ops &= propagate_rtx_1 (&op0, old, new, can_appear);
- valid_ops &= propagate_rtx_1 (&op1, old, new, can_appear);
+ valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
+ valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
tem = simplify_gen_relational (code, mode, op_mode, op0, op1);
op1 = XEXP (x, 1);
op2 = XEXP (x, 2);
op_mode = GET_MODE (op0);
- valid_ops &= propagate_rtx_1 (&op0, old, new, can_appear);
- valid_ops &= propagate_rtx_1 (&op1, old, new, can_appear);
- valid_ops &= propagate_rtx_1 (&op2, old, new, can_appear);
+ valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
+ valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
+ valid_ops &= propagate_rtx_1 (&op2, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1) && op2 == XEXP (x, 2))
return true;
if (op_mode == VOIDmode)
if (code == SUBREG)
{
op0 = XEXP (x, 0);
- valid_ops &= propagate_rtx_1 (&op0, old, new, can_appear);
+ valid_ops &= propagate_rtx_1 (&op0, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0))
return true;
tem = simplify_gen_subreg (mode, op0, GET_MODE (SUBREG_REG (x)),
break;
case RTX_OBJ:
- if (code == MEM && x != new)
+ if (code == MEM && x != new_rtx)
{
rtx new_op0;
op0 = XEXP (x, 0);
return true;
op0 = new_op0 = targetm.delegitimize_address (op0);
- valid_ops &= propagate_rtx_1 (&new_op0, old, new, true);
+ valid_ops &= propagate_rtx_1 (&new_op0, old_rtx, new_rtx,
+ flags | PR_CAN_APPEAR);
/* Dismiss transformation that we do not want to carry on. */
if (!valid_ops
canonicalize_address (new_op0);
/* Copy propagations are always ok. Otherwise check the costs. */
- if (!(REG_P (old) && REG_P (new))
- && !should_replace_address (op0, new_op0, GET_MODE (x)))
+ if (!(REG_P (old_rtx) && REG_P (new_rtx))
+ && !should_replace_address (op0, new_op0, GET_MODE (x),
+ flags & PR_OPTIMIZE_FOR_SPEED))
return true;
tem = replace_equiv_address_nv (x, new_op0);
/* The only simplification we do attempts to remove references to op0
or make it constant -- in both cases, op0's invalidity will not
make the result invalid. */
- propagate_rtx_1 (&op0, old, new, true);
- valid_ops &= propagate_rtx_1 (&op1, old, new, can_appear);
+ propagate_rtx_1 (&op0, old_rtx, new_rtx, flags | PR_CAN_APPEAR);
+ valid_ops &= propagate_rtx_1 (&op1, old_rtx, new_rtx, flags);
if (op0 == XEXP (x, 0) && op1 == XEXP (x, 1))
return true;
else if (code == REG)
{
- if (rtx_equal_p (x, old))
+ if (rtx_equal_p (x, old_rtx))
{
- *px = new;
+ *px = new_rtx;
return can_appear;
}
}
return valid_ops || can_appear || CONSTANT_P (tem);
}
+
+/* for_each_rtx traversal function that returns 1 if BODY points to
+ a non-constant mem. */
+
+static int
+varying_mem_p (rtx *body, void *data ATTRIBUTE_UNUSED)
+{
+ rtx x = *body;
+ return MEM_P (x) && !MEM_READONLY_P (x);
+}
+
+
/* Replace all occurrences of OLD in X with NEW and try to simplify the
resulting expression (in mode MODE). Return a new expression if it is
a constant, otherwise X.
Otherwise, we accept simplifications that have a lower or equal cost. */
static rtx
-propagate_rtx (rtx x, enum machine_mode mode, rtx old, rtx new)
+propagate_rtx (rtx x, enum machine_mode mode, rtx old_rtx, rtx new_rtx,
+ bool speed)
{
rtx tem;
bool collapsed;
+ int flags;
- if (REG_P (new) && REGNO (new) < FIRST_PSEUDO_REGISTER)
+ if (REG_P (new_rtx) && REGNO (new_rtx) < FIRST_PSEUDO_REGISTER)
return NULL_RTX;
- new = copy_rtx (new);
+ flags = 0;
+ if (REG_P (new_rtx) || CONSTANT_P (new_rtx))
+ flags |= PR_CAN_APPEAR;
+ if (!for_each_rtx (&new_rtx, varying_mem_p, NULL))
+ flags |= PR_HANDLE_MEM;
+
+ if (speed)
+ flags |= PR_OPTIMIZE_FOR_SPEED;
tem = x;
- collapsed = propagate_rtx_1 (&tem, old, new, REG_P (new) || CONSTANT_P (new));
+ collapsed = propagate_rtx_1 (&tem, old_rtx, copy_rtx (new_rtx), flags);
if (tem == x || !collapsed)
return NULL_RTX;
/* gen_lowpart_common will not be able to process VOIDmode entities other
than CONST_INTs. */
- if (GET_MODE (tem) == VOIDmode && GET_CODE (tem) != CONST_INT)
+ if (GET_MODE (tem) == VOIDmode && !CONST_INT_P (tem))
return NULL_RTX;
if (GET_MODE (tem) == VOIDmode)
between FROM to (but not including) TO. */
static bool
-local_ref_killed_between_p (struct df_ref * ref, rtx from, rtx to)
+local_ref_killed_between_p (df_ref ref, rtx from, rtx to)
{
rtx insn;
for (insn = from; insn != to; insn = NEXT_INSN (insn))
{
- struct df_ref **def_rec;
+ df_ref *def_rec;
if (!INSN_P (insn))
continue;
for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
{
- struct df_ref *def = *def_rec;
+ df_ref def = *def_rec;
if (DF_REF_REGNO (ref) == DF_REF_REGNO (def))
return true;
}
we check if the definition is killed after DEF_INSN or before
TARGET_INSN insn, in their respective basic blocks. */
static bool
-use_killed_between (struct df_ref *use, rtx def_insn, rtx target_insn)
+use_killed_between (df_ref use, rtx def_insn, rtx target_insn)
{
basic_block def_bb = BLOCK_FOR_INSN (def_insn);
basic_block target_bb = BLOCK_FOR_INSN (target_insn);
int regno;
- struct df_ref * def;
-
- /* In some obscure situations we can have a def reaching a use
- that is _before_ the def. In other words the def does not
- dominate the use even though the use and def are in the same
- basic block. This can happen when a register may be used
- uninitialized in a loop. In such cases, we must assume that
- DEF is not available. */
+ df_ref def;
+
+ /* We used to have a def reaching a use that is _before_ the def,
+ with the def not dominating the use even though the use and def
+ are in the same basic block, when a register may be used
+ uninitialized in a loop. This should not happen anymore since
+ we do not use reaching definitions, but still we test for such
+ cases and assume that DEF is not available. */
if (def_bb == target_bb
? DF_INSN_LUID (def_insn) >= DF_INSN_LUID (target_insn)
: !dominated_by_p (CDI_DOMINATORS, target_bb, def_bb))
return true;
/* Check if the reg in USE has only one definition. We already
- know that this definition reaches use, or we wouldn't be here. */
+ know that this definition reaches use, or we wouldn't be here.
+ However, this is invalid for hard registers because if they are
+ live at the beginning of the function it does not mean that we
+ have an uninitialized access. */
regno = DF_REF_REGNO (use);
def = DF_REG_DEF_CHAIN (regno);
- if (def && (def->next_reg == NULL))
+ if (def
+ && DF_REF_NEXT_REG (def) == NULL
+ && regno >= FIRST_PSEUDO_REGISTER)
return false;
/* Check locally if we are in the same basic block. */
if (single_pred_p (target_bb)
&& single_pred (target_bb) == def_bb)
{
- struct df_ref *x;
+ df_ref x;
/* See if USE is killed between DEF_INSN and the last insn in the
basic block containing DEF_INSN. */
x = df_bb_regno_last_def_find (def_bb, regno);
- if (x && DF_INSN_LUID (x->insn) >= DF_INSN_LUID (def_insn))
+ if (x && DF_INSN_LUID (DF_REF_INSN (x)) >= DF_INSN_LUID (def_insn))
return true;
/* See if USE is killed between TARGET_INSN and the first insn in the
basic block containing TARGET_INSN. */
x = df_bb_regno_first_def_find (target_bb, regno);
- if (x && DF_INSN_LUID (x->insn) < DF_INSN_LUID (target_insn))
+ if (x && DF_INSN_LUID (DF_REF_INSN (x)) < DF_INSN_LUID (target_insn))
return true;
return false;
}
-/* for_each_rtx traversal function that returns 1 if BODY points to
- a non-constant mem. */
-
-static int
-varying_mem_p (rtx *body, void *data ATTRIBUTE_UNUSED)
-{
- rtx x = *body;
- return MEM_P (x) && !MEM_READONLY_P (x);
-}
-
/* Check if all uses in DEF_INSN can be used in TARGET_INSN. This
would require full computation of available expressions;
we check only restricted conditions, see use_killed_between. */
static bool
all_uses_available_at (rtx def_insn, rtx target_insn)
{
- struct df_ref **use_rec;
+ df_ref *use_rec;
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (def_insn);
rtx def_set = single_set (def_insn);
gcc_assert (def_set);
/* If the insn uses the reg that it defines, the substitution is
invalid. */
- for (use_rec = DF_INSN_USES (def_insn); *use_rec; use_rec++)
+ for (use_rec = DF_INSN_INFO_USES (insn_info); *use_rec; use_rec++)
{
- struct df_ref *use = *use_rec;
+ df_ref use = *use_rec;
if (rtx_equal_p (DF_REF_REG (use), def_reg))
return false;
}
- for (use_rec = DF_INSN_EQ_USES (def_insn); *use_rec; use_rec++)
+ for (use_rec = DF_INSN_INFO_EQ_USES (insn_info); *use_rec; use_rec++)
{
- struct df_ref *use = *use_rec;
- if (rtx_equal_p (use->reg, def_reg))
+ df_ref use = *use_rec;
+ if (rtx_equal_p (DF_REF_REG (use), def_reg))
return false;
}
}
{
/* Look at all the uses of DEF_INSN, and see if they are not
killed between DEF_INSN and TARGET_INSN. */
- for (use_rec = DF_INSN_USES (def_insn); *use_rec; use_rec++)
+ for (use_rec = DF_INSN_INFO_USES (insn_info); *use_rec; use_rec++)
{
- struct df_ref *use = *use_rec;
+ df_ref use = *use_rec;
if (use_killed_between (use, def_insn, target_insn))
return false;
}
- for (use_rec = DF_INSN_EQ_USES (def_insn); *use_rec; use_rec++)
+ for (use_rec = DF_INSN_INFO_EQ_USES (insn_info); *use_rec; use_rec++)
{
- struct df_ref *use = *use_rec;
+ df_ref use = *use_rec;
if (use_killed_between (use, def_insn, target_insn))
return false;
}
}
- /* We don't do any analysis of memories or aliasing. Reject any
- instruction that involves references to non-constant memory. */
- return !for_each_rtx (&SET_SRC (def_set), varying_mem_p, NULL);
+ return true;
}
\f
in the data flow object of the pass. Mark any new uses as having the
given TYPE. */
static void
-update_df (rtx insn, rtx *loc, struct df_ref **use_rec, enum df_ref_type type,
+update_df (rtx insn, rtx *loc, df_ref *use_rec, enum df_ref_type type,
int new_flags)
{
bool changed = false;
/* Add a use for the registers that were propagated. */
while (*use_rec)
{
- struct df_ref *use = *use_rec;
- struct df_ref *orig_use = use, *new_use;
+ df_ref use = *use_rec;
+ df_ref orig_use = use, new_use;
+ int width = -1;
+ int offset = -1;
+ enum machine_mode mode = VOIDmode;
rtx *new_loc = find_occurrence (loc, DF_REF_REG (orig_use));
use_rec++;
if (!new_loc)
continue;
+ if (DF_REF_FLAGS_IS_SET (orig_use, DF_REF_SIGN_EXTRACT | DF_REF_ZERO_EXTRACT))
+ {
+ width = DF_REF_EXTRACT_WIDTH (orig_use);
+ offset = DF_REF_EXTRACT_OFFSET (orig_use);
+ mode = DF_REF_EXTRACT_MODE (orig_use);
+ }
+
/* Add a new insn use. Use the original type, because it says if the
use was within a MEM. */
new_use = df_ref_create (DF_REF_REG (orig_use), new_loc,
insn, BLOCK_FOR_INSN (insn),
- type, DF_REF_FLAGS (orig_use) | new_flags);
+ type, DF_REF_FLAGS (orig_use) | new_flags,
+ width, offset, mode);
/* Set up the use-def chain. */
- df_chain_copy (new_use, DF_REF_CHAIN (orig_use));
+ gcc_assert (DF_REF_ID (new_use) == (int) VEC_length (df_ref, use_def_ref));
+ VEC_safe_push (df_ref, heap, use_def_ref, get_def_for_use (orig_use));
changed = true;
}
if (changed)
performed. */
static bool
-try_fwprop_subst (struct df_ref *use, rtx *loc, rtx new, rtx def_insn, bool set_reg_equal)
+try_fwprop_subst (df_ref use, rtx *loc, rtx new_rtx, rtx def_insn, bool set_reg_equal)
{
rtx insn = DF_REF_INSN (use);
enum df_ref_type type = DF_REF_TYPE (use);
int flags = DF_REF_FLAGS (use);
-
+ rtx set = single_set (insn);
+ bool speed = optimize_bb_for_speed_p (BLOCK_FOR_INSN (insn));
+ int old_cost = 0;
+ bool ok;
+
+ /* forward_propagate_subreg may be operating on an instruction with
+ multiple sets. If so, assume the cost of the new instruction is
+ not greater than the old one. */
+ if (set)
+ old_cost = rtx_cost (SET_SRC (set), SET, speed);
if (dump_file)
{
fprintf (dump_file, "\nIn insn %d, replacing\n ", INSN_UID (insn));
print_inline_rtx (dump_file, *loc, 2);
fprintf (dump_file, "\n with ");
- print_inline_rtx (dump_file, new, 2);
+ print_inline_rtx (dump_file, new_rtx, 2);
fprintf (dump_file, "\n");
}
- if (validate_unshare_change (insn, loc, new, false))
+ validate_unshare_change (insn, loc, new_rtx, true);
+ if (!verify_changes (0))
+ {
+ if (dump_file)
+ fprintf (dump_file, "Changes to insn %d not recognized\n",
+ INSN_UID (insn));
+ ok = false;
+ }
+
+ else if (DF_REF_TYPE (use) == DF_REF_REG_USE
+ && set
+ && rtx_cost (SET_SRC (set), SET, speed) > old_cost)
+ {
+ if (dump_file)
+ fprintf (dump_file, "Changes to insn %d not profitable\n",
+ INSN_UID (insn));
+ ok = false;
+ }
+
+ else
{
- num_changes++;
if (dump_file)
fprintf (dump_file, "Changed insn %d\n", INSN_UID (insn));
+ ok = true;
+ }
+
+ if (ok)
+ {
+ confirm_change_group ();
+ num_changes++;
df_ref_remove (use);
- if (!CONSTANT_P (new))
+ if (!CONSTANT_P (new_rtx))
{
- update_df (insn, loc, DF_INSN_USES (def_insn), type, flags);
- update_df (insn, loc, DF_INSN_EQ_USES (def_insn), type, flags);
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (def_insn);
+ update_df (insn, loc, DF_INSN_INFO_USES (insn_info), type, flags);
+ update_df (insn, loc, DF_INSN_INFO_EQ_USES (insn_info), type, flags);
}
- return true;
}
else
{
- if (dump_file)
- fprintf (dump_file, "Changes to insn %d not recognized\n",
- INSN_UID (insn));
+ cancel_changes (0);
- /* Can also record a simplified value in a REG_EQUAL note, making a
- new one if one does not already exist. */
+ /* Can also record a simplified value in a REG_EQUAL note,
+ making a new one if one does not already exist. */
if (set_reg_equal)
{
if (dump_file)
fprintf (dump_file, " Setting REG_EQUAL note\n");
- set_unique_reg_note (insn, REG_EQUAL, copy_rtx (new));
+ set_unique_reg_note (insn, REG_EQUAL, copy_rtx (new_rtx));
/* ??? Is this still necessary if we add the note through
set_unique_reg_note? */
- if (!CONSTANT_P (new))
+ if (!CONSTANT_P (new_rtx))
{
- update_df (insn, loc, DF_INSN_USES (def_insn),
+ struct df_insn_info *insn_info = DF_INSN_INFO_GET (def_insn);
+ update_df (insn, loc, DF_INSN_INFO_USES (insn_info),
type, DF_REF_IN_NOTE);
- update_df (insn, loc, DF_INSN_EQ_USES (def_insn),
+ update_df (insn, loc, DF_INSN_INFO_EQ_USES (insn_info),
type, DF_REF_IN_NOTE);
}
}
-
- return false;
}
+
+ return ok;
}
+#ifdef LOAD_EXTEND_OP
+static df_ref
+get_reg_use_in (rtx insn, rtx reg)
+{
+ df_ref *use_vec;
-/* If USE is a paradoxical subreg, see if it can be replaced by a pseudo. */
+ for (use_vec = DF_INSN_USES (insn); *use_vec; use_vec++)
+ {
+ df_ref use = *use_vec;
+
+ if (!DF_REF_IS_ARTIFICIAL (use)
+ && DF_REF_TYPE (use) == DF_REF_REG_USE
+ && DF_REF_REG (use) == reg)
+ return use;
+ }
+ return NULL;
+}
+#endif
+
+/* If USE is a subreg, see if it can be replaced by a pseudo. */
static bool
-forward_propagate_subreg (struct df_ref *use, rtx def_insn, rtx def_set)
+forward_propagate_subreg (df_ref use, rtx def_insn, rtx def_set)
{
rtx use_reg = DF_REF_REG (use);
rtx use_insn, src;
- /* Only consider paradoxical subregs... */
+ /* Only consider subregs... */
enum machine_mode use_mode = GET_MODE (use_reg);
if (GET_CODE (use_reg) != SUBREG
- || !REG_P (SET_DEST (def_set))
- || GET_MODE_SIZE (use_mode)
- <= GET_MODE_SIZE (GET_MODE (SUBREG_REG (use_reg))))
+ || !REG_P (SET_DEST (def_set)))
return false;
- /* If this is a paradoxical SUBREG, we have no idea what value the
- extra bits would have. However, if the operand is equivalent to
- a SUBREG whose operand is the same as our mode, and all the modes
- are within a word, we can just use the inner operand because
- these SUBREGs just say how to treat the register. */
- use_insn = DF_REF_INSN (use);
+ /* If this is a paradoxical SUBREG... */
+ if (GET_MODE_SIZE (use_mode)
+ > GET_MODE_SIZE (GET_MODE (SUBREG_REG (use_reg))))
+ {
+ /* If this is a paradoxical SUBREG, we have no idea what value the
+ extra bits would have. However, if the operand is equivalent to
+ a SUBREG whose operand is the same as our mode, and all the modes
+ are within a word, we can just use the inner operand because
+ these SUBREGs just say how to treat the register. */
+ use_insn = DF_REF_INSN (use);
+ src = SET_SRC (def_set);
+ if (GET_CODE (src) == SUBREG
+ && REG_P (SUBREG_REG (src))
+ && GET_MODE (SUBREG_REG (src)) == use_mode
+ && subreg_lowpart_p (src)
+ && all_uses_available_at (def_insn, use_insn))
+ return try_fwprop_subst (use, DF_REF_LOC (use), SUBREG_REG (src),
+ def_insn, false);
+ }
+
+ /* If this is a SUBREG of a ZERO_EXTEND or SIGN_EXTEND, and the SUBREG
+ is the low part of the reg being extended then just use the inner
+ operand. Don't do this if the ZERO_EXTEND or SIGN_EXTEND insn will
+ be removed due to it matching a LOAD_EXTEND_OP load from memory. */
+ else if (subreg_lowpart_p (use_reg))
+ {
+#ifdef LOAD_EXTEND_OP
+ df_ref prev_use, prev_def;
+#endif
+ use_insn = DF_REF_INSN (use);
+ src = SET_SRC (def_set);
+ if ((GET_CODE (src) == ZERO_EXTEND
+ || GET_CODE (src) == SIGN_EXTEND)
+ && REG_P (XEXP (src, 0))
+ && GET_MODE (XEXP (src, 0)) == use_mode
+#ifdef LOAD_EXTEND_OP
+ && !(LOAD_EXTEND_OP (use_mode) == GET_CODE (src)
+ && (prev_use = get_reg_use_in (def_insn, XEXP (src, 0))) != NULL
+ && (prev_def = get_def_for_use (prev_use)) != NULL
+ && !DF_REF_IS_ARTIFICIAL (prev_def)
+ && NONJUMP_INSN_P (DF_REF_INSN (prev_def))
+ && GET_CODE (PATTERN (DF_REF_INSN (prev_def))) == SET
+ && GET_CODE (SET_SRC (PATTERN (DF_REF_INSN (prev_def)))) == MEM
+ && rtx_equal_p (SET_DEST (PATTERN (DF_REF_INSN (prev_def))),
+ XEXP (src, 0)))
+#endif
+ && all_uses_available_at (def_insn, use_insn))
+ return try_fwprop_subst (use, DF_REF_LOC (use), XEXP (src, 0),
+ def_insn, false);
+ }
+
+ return false;
+}
+
+/* Try to replace USE with SRC (defined in DEF_INSN) in __asm. */
+
+static bool
+forward_propagate_asm (df_ref use, rtx def_insn, rtx def_set, rtx reg)
+{
+ rtx use_insn = DF_REF_INSN (use), src, use_pat, asm_operands, new_rtx, *loc;
+ int speed_p, i;
+ df_ref *use_vec;
+
+ gcc_assert ((DF_REF_FLAGS (use) & DF_REF_IN_NOTE) == 0);
+
src = SET_SRC (def_set);
- if (GET_CODE (src) == SUBREG
- && REG_P (SUBREG_REG (src))
- && GET_MODE (SUBREG_REG (src)) == use_mode
- && subreg_lowpart_p (src)
- && all_uses_available_at (def_insn, use_insn))
- return try_fwprop_subst (use, DF_REF_LOC (use), SUBREG_REG (src),
- def_insn, false);
- else
+ use_pat = PATTERN (use_insn);
+
+ /* In __asm don't replace if src might need more registers than
+ reg, as that could increase register pressure on the __asm. */
+ use_vec = DF_INSN_USES (def_insn);
+ if (use_vec[0] && use_vec[1])
return false;
+
+ speed_p = optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn));
+ asm_operands = NULL_RTX;
+ switch (GET_CODE (use_pat))
+ {
+ case ASM_OPERANDS:
+ asm_operands = use_pat;
+ break;
+ case SET:
+ if (MEM_P (SET_DEST (use_pat)))
+ {
+ loc = &SET_DEST (use_pat);
+ new_rtx = propagate_rtx (*loc, GET_MODE (*loc), reg, src, speed_p);
+ if (new_rtx)
+ validate_unshare_change (use_insn, loc, new_rtx, true);
+ }
+ asm_operands = SET_SRC (use_pat);
+ break;
+ case PARALLEL:
+ for (i = 0; i < XVECLEN (use_pat, 0); i++)
+ if (GET_CODE (XVECEXP (use_pat, 0, i)) == SET)
+ {
+ if (MEM_P (SET_DEST (XVECEXP (use_pat, 0, i))))
+ {
+ loc = &SET_DEST (XVECEXP (use_pat, 0, i));
+ new_rtx = propagate_rtx (*loc, GET_MODE (*loc), reg,
+ src, speed_p);
+ if (new_rtx)
+ validate_unshare_change (use_insn, loc, new_rtx, true);
+ }
+ asm_operands = SET_SRC (XVECEXP (use_pat, 0, i));
+ }
+ else if (GET_CODE (XVECEXP (use_pat, 0, i)) == ASM_OPERANDS)
+ asm_operands = XVECEXP (use_pat, 0, i);
+ break;
+ default:
+ gcc_unreachable ();
+ }
+
+ gcc_assert (asm_operands && GET_CODE (asm_operands) == ASM_OPERANDS);
+ for (i = 0; i < ASM_OPERANDS_INPUT_LENGTH (asm_operands); i++)
+ {
+ loc = &ASM_OPERANDS_INPUT (asm_operands, i);
+ new_rtx = propagate_rtx (*loc, GET_MODE (*loc), reg, src, speed_p);
+ if (new_rtx)
+ validate_unshare_change (use_insn, loc, new_rtx, true);
+ }
+
+ if (num_changes_pending () == 0 || !apply_change_group ())
+ return false;
+
+ num_changes++;
+ return true;
}
/* Try to replace USE with SRC (defined in DEF_INSN) and simplify the
result. */
static bool
-forward_propagate_and_simplify (struct df_ref *use, rtx def_insn, rtx def_set)
+forward_propagate_and_simplify (df_ref use, rtx def_insn, rtx def_set)
{
rtx use_insn = DF_REF_INSN (use);
rtx use_set = single_set (use_insn);
- rtx src, reg, new, *loc;
+ rtx src, reg, new_rtx, *loc;
bool set_reg_equal;
enum machine_mode mode;
+ int asm_use = -1;
- if (!use_set)
+ if (INSN_CODE (use_insn) < 0)
+ asm_use = asm_noperands (PATTERN (use_insn));
+
+ if (!use_set && asm_use < 0)
return false;
/* Do not propagate into PC, CC0, etc. */
- if (GET_MODE (SET_DEST (use_set)) == VOIDmode)
+ if (use_set && GET_MODE (SET_DEST (use_set)) == VOIDmode)
return false;
/* If def and use are subreg, check if they match. */
if (MEM_P (src) && MEM_READONLY_P (src))
{
rtx x = avoid_constant_pool_reference (src);
- if (x != src)
+ if (x != src && use_set)
{
rtx note = find_reg_note (use_insn, REG_EQUAL, NULL_RTX);
- rtx old = note ? XEXP (note, 0) : SET_SRC (use_set);
- rtx new = simplify_replace_rtx (old, src, x);
- if (old != new)
- set_unique_reg_note (use_insn, REG_EQUAL, copy_rtx (new));
+ rtx old_rtx = note ? XEXP (note, 0) : SET_SRC (use_set);
+ rtx new_rtx = simplify_replace_rtx (old_rtx, src, x);
+ if (old_rtx != new_rtx)
+ set_unique_reg_note (use_insn, REG_EQUAL, copy_rtx (new_rtx));
}
return false;
}
+ if (asm_use >= 0)
+ return forward_propagate_asm (use, def_insn, def_set, reg);
+
/* Else try simplifying. */
if (DF_REF_TYPE (use) == DF_REF_REG_MEM_STORE)
else
mode = GET_MODE (*loc);
- new = propagate_rtx (*loc, mode, reg, src);
+ new_rtx = propagate_rtx (*loc, mode, reg, src,
+ optimize_bb_for_speed_p (BLOCK_FOR_INSN (use_insn)));
- if (!new)
+ if (!new_rtx)
return false;
- return try_fwprop_subst (use, loc, new, def_insn, set_reg_equal);
+ return try_fwprop_subst (use, loc, new_rtx, def_insn, set_reg_equal);
}
definition, try to forward propagate it into that insn. */
static void
-forward_propagate_into (struct df_ref *use)
+forward_propagate_into (df_ref use)
{
- struct df_link *defs;
- struct df_ref *def;
+ df_ref def;
rtx def_insn, def_set, use_insn;
rtx parent;
return;
/* Only consider uses that have a single definition. */
- defs = DF_REF_CHAIN (use);
- if (!defs || defs->next)
+ def = get_def_for_use (use);
+ if (!def)
return;
-
- def = defs->ref;
if (DF_REF_FLAGS (def) & DF_REF_READ_WRITE)
return;
if (DF_REF_IS_ARTIFICIAL (def))
else
parent = PATTERN (use_insn);
- if (!loc_mentioned_in_p (DF_REF_LOC (use), parent))
+ if (!reg_mentioned_p (DF_REF_REG (use), parent))
return;
def_insn = DF_REF_INSN (def);
insns (sadly) if we are not working in cfglayout mode. */
loop_optimizer_init (0);
- /* Now set up the dataflow problem (we only want use-def chains) and
- put the dataflow solver to work. */
- df_set_flags (DF_EQ_NOTES);
- df_chain_add_problem (DF_UD_CHAIN);
- df_analyze ();
- df_maybe_reorganize_use_refs (DF_REF_ORDER_BY_INSN_WITH_NOTES);
+ build_single_def_use_links ();
df_set_flags (DF_DEFER_INSN_RESCAN);
}
{
loop_optimizer_finalize ();
+ VEC_free (df_ref, heap, use_def_ref);
free_dominance_info (CDI_DOMINATORS);
cleanup_cfg (0);
delete_trivially_dead_insns (get_insns (), max_reg_num ());
fprintf (dump_file,
"\nNumber of successful forward propagations: %d\n\n",
num_changes);
+ df_remove_problem (df_chain);
}
for (i = 0; i < DF_USES_TABLE_SIZE (); i++)
{
- struct df_ref *use = DF_USES_GET (i);
+ df_ref use = DF_USES_GET (i);
if (use)
if (DF_REF_TYPE (use) == DF_REF_REG_USE
- || DF_REF_BB (use)->loop_father == NULL)
+ || DF_REF_BB (use)->loop_father == NULL
+ /* The outer most loop is not really a loop. */
+ || loop_outer (DF_REF_BB (use)->loop_father) == NULL)
forward_propagate_into (use);
}
return 0;
}
-struct tree_opt_pass pass_rtl_fwprop =
+struct rtl_opt_pass pass_rtl_fwprop =
{
+ {
+ RTL_PASS,
"fwprop1", /* name */
gate_fwprop, /* gate */
fwprop, /* execute */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_df_finish |
- TODO_dump_func, /* todo_flags_finish */
- 0 /* letter */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_dump_func /* todo_flags_finish */
+ }
};
static unsigned int
/* Go through all the uses. update_df will create new ones at the
end, and we'll go through them as well. */
- df_set_flags (DF_DEFER_INSN_RESCAN);
-
for (i = 0; i < DF_USES_TABLE_SIZE (); i++)
{
- struct df_ref *use = DF_USES_GET (i);
+ df_ref use = DF_USES_GET (i);
if (use)
if (DF_REF_TYPE (use) != DF_REF_REG_USE
- && DF_REF_BB (use)->loop_father != NULL)
+ && DF_REF_BB (use)->loop_father != NULL
+ /* The outer most loop is not really a loop. */
+ && loop_outer (DF_REF_BB (use)->loop_father) != NULL)
forward_propagate_into (use);
}
return 0;
}
-struct tree_opt_pass pass_rtl_fwprop_addr =
+struct rtl_opt_pass pass_rtl_fwprop_addr =
{
+ {
+ RTL_PASS,
"fwprop2", /* name */
gate_fwprop, /* gate */
fwprop_addr, /* execute */
0, /* properties_provided */
0, /* properties_destroyed */
0, /* todo_flags_start */
- TODO_df_finish |
- TODO_dump_func, /* todo_flags_finish */
- 0 /* letter */
+ TODO_df_finish | TODO_verify_rtl_sharing |
+ TODO_dump_func /* todo_flags_finish */
+ }
};
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