On 09/13/2013 11:11 AM, Andrew MacLeod wrote:
On 09/13/2013 03:54 AM, Richard Biener wrote:
On Thu, Sep 12, 2013 at 11:09 PM, Andrew MacLeod
<amacl...@redhat.com> wrote:
There are 2 parts of tre-ssa-ter.c to address.
is_replaceable_p() is also used in expr.c, It has a flag to indicate
where
its being called from, and we do different checks for each one.
There is a
wrapper function stmt_is_replaceable_p() in tree-ssa-ter.c which
hides the
setting of the flag to expr.c. Most of the function is common, so I
extracted out the common part, and put it in tree-ssa.c.
I then moved stmt_is_replaceable() to expr.c, has it call the common
routine
and then added the extra bit it needs there. Similarly
tree-ssa-ter.c gets
ter_is_replaceable_p() which calls the common part, and then does
its own
special checking. This removes that general export and messiness from
tree-ssa-ter.c
I think I got the logic of the function right, but you might want to
double
check... It was giving me a headache when I split it :-)
Unfortunately, tree-ssa-ter.c also has 2 functions
(find_replaceable_exprs() and dump_replaceable_exprs()) which are
exported
and utilized by tree-outof-ssa.c (the file is a part of the out-of-ssa
module). So I moved the prototypes from tree-ssa-live.h into a newly
created tree-ssa-ter.h file, and included it directly from
tree-outof-ssa.c, the only consumer.
I also could have just left the is_replaceable_p() function as is,
put the
prototype and the 'stmt_is_replaceable_p()' wrapper function in
tree-ssa-ter.h, and then included that from expr.c... but it just
seems
like an odd thing to include directly there.... but that is an
option...
eventually we mighty want to look at splitting expr.c.. it seems a bit
multi-personality with some pure RTL, some tree/rtl and some
ssa... even
though they all serve the same ultimate function, it is 11,000+
lines long
now :-) . A task for another day.
is_replaceable_p and friends is purely specific to the area of RTL
expansion,
so putting it in tree-ssa.[ch] is definitely wrong. It doesn't make
sense to
use it anywhere else.
The main driver of the RTL expansion process is in cfgexpand.c (the
expand
pass itself) in gimple_expand_cfg. We have one header file related to
the RTL expansion process and is_replaceable_p would simply fit in
ssaexpand.h (which doesn't have a .c file, so leaving the stuff in
the .c files
where they are now is ok).
So - I fear you have to re-do this patch (in a much simpler way).
I actually figured as much :-) I had actually done that split before
I remembered there were other exports, and considered undoing that
part, but figured since I had done it I'd get opinion :-)
Or are you suggesting we also bail on tree-ssa-ter.h and put those
prototypes in ssaexpand.h?
If we want to make this fully consistent (.h's match .c exports) , I
could put is_replaceable_p() into a new ssaexpand.c, move the 3
tree-outof-ssa prototypes in ssaexpand.h into tree-outof-ssa.h, and
have ssaexpand.h include tree-ssa-ter.h and tree-outof-ssa.h. That
would then be clean. and consistent.
actually, we could just make is_replaceable_p() static inline in
ssaexpand.h... thats not unreasonable either, but we'll probably find
functions which belong in ssaexpand.c sooner or later.
No worries, I figured these first few patches would be slower and more
painful until a reasonable formula was determined :-)
Andrew
OK, a slightly different take..
I realized that I should be adding tree-outof-ssa.h to handle the 3
exports from tree-outof-ssa.c that are in ssaexpand.h... In fact, by
far the most sensible thing to do is to simply rename tree-outof-ssa.c
to ssaexpand.c. This actually resolves a number of warts... And
is_replaceable_p() very naturally fits in ssaexpand.c now...
what do you think of this option? :-) and svn rename preserves all the
tree-outof-ssa.c history...
Andrew
* tree-ssa-live.h (find_replaceable_exprs, dump_replaceable_exprs): Move
prototypes to...
* tree-ssa-ter.h: New. Move prototypes here.
* tree-flow.h (stmt_is_replaceable_p): Move prototype to...
* ssaexpand.h: Here. Include tree-ssa-ter.h
* expr.c (stmt_is_replaceable_p): Relocate from tree-ssa-ter.c. Use
newly refactored ssa_is_replaceable_p.
* tree-ssa-ter.c (is_replaceable_p, stmt_is_replaceable_p): Delete.
(ter_is_replaceable_p): Use new refactored ssa_is_replaceable_p.
(process_replaceable): Use ter_is_replaceable_p.
(find_replaceable_in_bb): Use ter_is_replaceable_p.
* Makefile.in: Update Dependencies and object files..
* ssaexpand.c: Renamed from tree-outof-ssa.c.
(ssa_is_replaceable_p): Import common bits of is_replaceable_p.
* tree-outof-ssa.c: Delete.
Index: tree-ssa-live.h
===================================================================
--- tree-ssa-live.h (revision 202567)
+++ tree-ssa-live.h (working copy)
@@ -325,10 +325,4 @@
/* From tree-ssa-coalesce.c */
extern var_map coalesce_ssa_name (void);
-
-/* From tree-ssa-ter.c */
-extern bitmap find_replaceable_exprs (var_map);
-extern void dump_replaceable_exprs (FILE *, bitmap);
-
-
#endif /* _TREE_SSA_LIVE_H */
Index: tree-ssa-ter.h
===================================================================
--- tree-ssa-ter.h (revision 0)
+++ tree-ssa-ter.h (working copy)
@@ -0,0 +1,26 @@
+/* Header file for tree-ssa-ter.c exports.
+ Copyright (C) 2013 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 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 COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#ifndef GCC_TREE_SSA_TER_H
+#define GCC_TREE_SSA_TER_H
+
+extern bitmap find_replaceable_exprs (var_map);
+extern void dump_replaceable_exprs (FILE *, bitmap);
+
+#endif /* GCC_TREE_SSA_TER_H */
Index: tree-flow.h
===================================================================
--- tree-flow.h (revision 202567)
+++ tree-flow.h (working copy)
@@ -686,9 +686,6 @@
/* In ipa-pure-const.c */
void warn_function_noreturn (tree);
-/* In tree-ssa-ter.c */
-bool stmt_is_replaceable_p (gimple);
-
/* In tree-parloops.c */
bool parallelized_function_p (tree);
Index: ssaexpand.h
===================================================================
--- ssaexpand.h (revision 202567)
+++ ssaexpand.h (working copy)
@@ -22,6 +22,7 @@
#define _SSAEXPAND_H 1
#include "tree-ssa-live.h"
+#include "tree-ssa-ter.h"
/* This structure (of which only a singleton SA exists) is used to
pass around information between the outof-SSA functions, cfgexpand
@@ -71,9 +72,9 @@
return NULL;
}
-/* In tree-outof-ssa.c. */
-void finish_out_of_ssa (struct ssaexpand *sa);
-unsigned int rewrite_out_of_ssa (struct ssaexpand *sa);
-void expand_phi_nodes (struct ssaexpand *sa);
+extern bool ssa_is_replaceable_p (gimple stmt);
+extern void finish_out_of_ssa (struct ssaexpand *sa);
+extern unsigned int rewrite_out_of_ssa (struct ssaexpand *sa);
+extern void expand_phi_nodes (struct ssaexpand *sa);
#endif
Index: expr.c
===================================================================
--- expr.c (revision 202567)
+++ expr.c (working copy)
@@ -9176,6 +9176,24 @@
}
#undef REDUCE_BIT_FIELD
+
+/* Return TRUE if expression STMT is suitable for replacement.
+ Never consider memory loads as replaceable, because those don't ever lead
+ into constant expressions. */
+
+static bool
+stmt_is_replaceable_p (gimple stmt)
+{
+ if (ssa_is_replaceable_p (stmt))
+ {
+ /* Don't move around loads. */
+ if (!gimple_assign_single_p (stmt)
+ || is_gimple_val (gimple_assign_rhs1 (stmt)))
+ return true;
+ }
+ return false;
+}
+
rtx
expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode,
enum expand_modifier modifier, rtx *alt_rtl)
Index: tree-ssa-ter.c
===================================================================
--- tree-ssa-ter.c (revision 202567)
+++ tree-ssa-ter.c (working copy)
@@ -28,7 +28,7 @@
#include "bitmap.h"
#include "tree-ssa.h"
#include "dumpfile.h"
-#include "tree-ssa-live.h"
+#include "ssaexpand.h"
#include "flags.h"
@@ -46,7 +46,7 @@
information is tracked.
Variables which only have one use, and whose defining stmt is considered
- a replaceable expression (see is_replaceable_p) are tracked to see whether
+ a replaceable expression (see ssa_is_replaceable_p) are tracked to see whether
they can be replaced at their use location.
n_12 = C * 10
@@ -359,111 +359,6 @@
}
-/* Return TRUE if expression STMT is suitable for replacement.
- TER is true if is_replaceable_p is called from within TER, false
- when used from within stmt_is_replaceable_p, i.e. EXPAND_INITIALIZER
- expansion. The differences are that with !TER some tests are skipped
- to make it more aggressive (doesn't require the same bb, or for -O0
- same locus and same BLOCK), on the other side never considers memory
- loads as replaceable, because those don't ever lead into constant
- expressions. */
-
-static inline bool
-is_replaceable_p (gimple stmt, bool ter)
-{
- use_operand_p use_p;
- tree def;
- gimple use_stmt;
- location_t locus1, locus2;
- tree block1, block2;
-
- /* Only consider modify stmts. */
- if (!is_gimple_assign (stmt))
- return false;
-
- /* If the statement may throw an exception, it cannot be replaced. */
- if (stmt_could_throw_p (stmt))
- return false;
-
- /* Punt if there is more than 1 def. */
- def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
- if (!def)
- return false;
-
- /* Only consider definitions which have a single use. */
- if (!single_imm_use (def, &use_p, &use_stmt))
- return false;
-
- /* If the use isn't in this block, it wont be replaced either. */
- if (ter && gimple_bb (use_stmt) != gimple_bb (stmt))
- return false;
-
- locus1 = gimple_location (stmt);
- block1 = LOCATION_BLOCK (locus1);
- locus1 = LOCATION_LOCUS (locus1);
-
- if (gimple_code (use_stmt) == GIMPLE_PHI)
- locus2 = gimple_phi_arg_location (use_stmt, PHI_ARG_INDEX_FROM_USE (use_p));
- else
- locus2 = gimple_location (use_stmt);
- block2 = LOCATION_BLOCK (locus2);
- locus2 = LOCATION_LOCUS (locus2);
-
- if ((!optimize || optimize_debug)
- && ter
- && ((locus1 != UNKNOWN_LOCATION
- && locus1 != locus2)
- || (block1 != NULL_TREE
- && block1 != block2)))
- return false;
-
- /* Used in this block, but at the TOP of the block, not the end. */
- if (gimple_code (use_stmt) == GIMPLE_PHI)
- return false;
-
- /* There must be no VDEFs. */
- if (gimple_vdef (stmt))
- return false;
-
- /* Without alias info we can't move around loads. */
- if ((!optimize || !ter)
- && gimple_assign_single_p (stmt)
- && !is_gimple_val (gimple_assign_rhs1 (stmt)))
- return false;
-
- /* Float expressions must go through memory if float-store is on. */
- if (flag_float_store
- && FLOAT_TYPE_P (gimple_expr_type (stmt)))
- return false;
-
- /* An assignment with a register variable on the RHS is not
- replaceable. */
- if (gimple_assign_rhs_code (stmt) == VAR_DECL
- && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt)))
- return false;
-
- /* No function calls can be replaced. */
- if (is_gimple_call (stmt))
- return false;
-
- /* Leave any stmt with volatile operands alone as well. */
- if (gimple_has_volatile_ops (stmt))
- return false;
-
- return true;
-}
-
-
-/* Variant of is_replaceable_p test for use in EXPAND_INITIALIZER
- expansion. */
-
-bool
-stmt_is_replaceable_p (gimple stmt)
-{
- return is_replaceable_p (stmt, false);
-}
-
-
/* This function will remove the expression for VERSION from replacement
consideration in table TAB. If FREE_EXPR is true, then remove the
expression from consideration as well by freeing the decl uid bitmap. */
@@ -487,6 +382,62 @@
}
+/* Return TRUE if expression STMT is suitable for replacement.
+ In addition to ssa_is_replaceable_p, require the same bb, and for -O0
+ same locus and same BLOCK), Considers memory loads as replaceable if aliasing
+ is available. */
+
+static inline bool
+ter_is_replaceable_p (gimple stmt)
+{
+
+ if (ssa_is_replaceable_p (stmt))
+ {
+ use_operand_p use_p;
+ tree def;
+ gimple use_stmt;
+ location_t locus1, locus2;
+ tree block1, block2;
+
+ /* Only consider definitions which have a single use. ssa_is_replaceable_p
+ already performed this check, but the use stmt pointer is required for
+ further checks. */
+ def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
+ if (!single_imm_use (def, &use_p, &use_stmt))
+ return false;
+
+ /* If the use isn't in this block, it wont be replaced either. */
+ if (gimple_bb (use_stmt) != gimple_bb (stmt))
+ return false;
+
+ locus1 = gimple_location (stmt);
+ block1 = LOCATION_BLOCK (locus1);
+ locus1 = LOCATION_LOCUS (locus1);
+
+ if (gimple_code (use_stmt) == GIMPLE_PHI)
+ locus2 = gimple_phi_arg_location (use_stmt,
+ PHI_ARG_INDEX_FROM_USE (use_p));
+ else
+ locus2 = gimple_location (use_stmt);
+ block2 = LOCATION_BLOCK (locus2);
+ locus2 = LOCATION_LOCUS (locus2);
+
+ if ((!optimize || optimize_debug)
+ && ((locus1 != UNKNOWN_LOCATION && locus1 != locus2)
+ || (block1 != NULL_TREE && block1 != block2)))
+ return false;
+
+ /* Without alias info we can't move around loads. */
+ if (!optimize && gimple_assign_single_p (stmt)
+ && !is_gimple_val (gimple_assign_rhs1 (stmt)))
+ return false;
+
+ return true;
+ }
+ return false;
+}
+
+
/* Create an expression entry for a replaceable expression. */
static void
@@ -497,7 +448,7 @@
ssa_op_iter iter;
bitmap def_vars, use_vars;
- gcc_checking_assert (is_replaceable_p (stmt, true));
+ gcc_checking_assert (ter_is_replaceable_p (stmt));
def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
version = SSA_NAME_VERSION (def);
@@ -612,7 +563,7 @@
if (is_gimple_debug (stmt))
continue;
- stmt_replaceable = is_replaceable_p (stmt, true);
+ stmt_replaceable = ter_is_replaceable_p (stmt);
/* Determine if this stmt finishes an existing expression. */
FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)
Index: Makefile.in
===================================================================
--- Makefile.in (revision 202567)
+++ Makefile.in (working copy)
@@ -950,7 +950,7 @@
TREE_SSA_H = tree-ssa.h $(TREE_FLOW_H)
TREE_HASHER_H = tree-hasher.h $(HASH_TABLE_H) $(TREE_FLOW_H)
TREE_SSA_LIVE_H = tree-ssa-live.h $(PARTITION_H)
-SSAEXPAND_H = ssaexpand.h $(TREE_SSA_LIVE_H)
+SSAEXPAND_H = ssaexpand.h $(TREE_SSA_LIVE_H) tree-ssa-ter.h
PRETTY_PRINT_H = pretty-print.h $(INPUT_H) $(OBSTACK_H)
TREE_PRETTY_PRINT_H = tree-pretty-print.h $(PRETTY_PRINT_H)
GIMPLE_PRETTY_PRINT_H = gimple-pretty-print.h $(TREE_PRETTY_PRINT_H)
@@ -1370,6 +1370,7 @@
simplify-rtx.o \
sparseset.o \
sreal.o \
+ ssaexpand.o \
stack-ptr-mod.o \
statistics.o \
stmt.o \
@@ -1408,7 +1409,6 @@
tree-nrv.o \
tree-object-size.o \
tree-optimize.o \
- tree-outof-ssa.o \
tree-parloops.o \
tree-phinodes.o \
tree-predcom.o \
@@ -2309,16 +2309,15 @@
$(GIMPLE_H) $(TREE_INLINE_H) $(GIMPLE_PRETTY_PRINT_H)
tree-ssa-ter.o : tree-ssa-ter.c $(TREE_SSA_H) $(CONFIG_H) $(SYSTEM_H) \
$(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h $(DUMPFILE_H) \
- $(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) \
- $(GIMPLE_PRETTY_PRINT_H)
+ $(SSAEXPAND_H) $(BITMAP_H) $(FLAGS_H) $(GIMPLE_PRETTY_PRINT_H)
tree-ssa-coalesce.o : tree-ssa-coalesce.c $(TREE_SSA_H) $(CONFIG_H) \
$(SYSTEM_H) $(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h $(DUMPFILE_H) \
$(TREE_SSA_LIVE_H) $(BITMAP_H) $(FLAGS_H) $(HASH_TABLE_H) \
$(TREE_PRETTY_PRINT_H)
-tree-outof-ssa.o : tree-outof-ssa.c $(TREE_SSA_H) $(CONFIG_H) $(SYSTEM_H) \
+ssaexpand.o : ssaexpand.c $(TREE_SSA_H) $(CONFIG_H) $(SYSTEM_H) \
$(TREE_H) $(DIAGNOSTIC_H) $(TM_H) coretypes.h $(DUMPFILE_H) \
$(TREE_SSA_LIVE_H) $(BASIC_BLOCK_H) $(BITMAP_H) $(GGC_H) \
- $(EXPR_H) $(SSAEXPAND_H) $(GIMPLE_PRETTY_PRINT_H)
+ $(EXPR_H) $(SSAEXPAND_H) $(GIMPLE_PRETTY_PRINT_H)
tree-ssa-dse.o : tree-ssa-dse.c $(CONFIG_H) $(SYSTEM_H) coretypes.h \
$(TM_H) $(GGC_H) $(TREE_H) $(TM_P_H) $(BASIC_BLOCK_H) \
$(TREE_SSA_H) $(TREE_PASS_H) domwalk.h $(FLAGS_H) \
Index: ssaexpand.c
===================================================================
--- ssaexpand.c (working copy)
+++ ssaexpand.c (working copy)
@@ -37,7 +37,63 @@
#include "expr.h"
+/* Return TRUE if expression STMT is suitable for replacement. */
+bool
+ssa_is_replaceable_p (gimple stmt)
+{
+ use_operand_p use_p;
+ tree def;
+ gimple use_stmt;
+
+ /* Only consider modify stmts. */
+ if (!is_gimple_assign (stmt))
+ return false;
+
+ /* If the statement may throw an exception, it cannot be replaced. */
+ if (stmt_could_throw_p (stmt))
+ return false;
+
+ /* Punt if there is more than 1 def. */
+ def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF);
+ if (!def)
+ return false;
+
+ /* Only consider definitions which have a single use. */
+ if (!single_imm_use (def, &use_p, &use_stmt))
+ return false;
+
+ /* Used in this block, but at the TOP of the block, not the end. */
+ if (gimple_code (use_stmt) == GIMPLE_PHI)
+ return false;
+
+ /* There must be no VDEFs. */
+ if (gimple_vdef (stmt))
+ return false;
+
+ /* Float expressions must go through memory if float-store is on. */
+ if (flag_float_store
+ && FLOAT_TYPE_P (gimple_expr_type (stmt)))
+ return false;
+
+ /* An assignment with a register variable on the RHS is not
+ replaceable. */
+ if (gimple_assign_rhs_code (stmt) == VAR_DECL
+ && DECL_HARD_REGISTER (gimple_assign_rhs1 (stmt)))
+ return false;
+
+ /* No function calls can be replaced. */
+ if (is_gimple_call (stmt))
+ return false;
+
+ /* Leave any stmt with volatile operands alone as well. */
+ if (gimple_has_volatile_ops (stmt))
+ return false;
+
+ return true;
+}
+
+
/* Used to hold all the components required to do SSA PHI elimination.
The node and pred/succ list is a simple linear list of nodes and
edges represented as pairs of nodes.
Index: tree-outof-ssa.c
===================================================================
--- tree-outof-ssa.c (revision 202567)
+++ tree-outof-ssa.c (working copy)
@@ -1,1139 +0,0 @@
-/* Convert a program in SSA form into Normal form.
- Copyright (C) 2004-2013 Free Software Foundation, Inc.
- Contributed by Andrew Macleod <amacl...@redhat.com>
-
-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 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 COPYING3. If not see
-<http://www.gnu.org/licenses/>. */
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "tm.h"
-#include "tree.h"
-#include "ggc.h"
-#include "basic-block.h"
-#include "gimple-pretty-print.h"
-#include "bitmap.h"
-#include "tree-ssa.h"
-#include "dumpfile.h"
-#include "diagnostic-core.h"
-#include "ssaexpand.h"
-
-/* FIXME: A lot of code here deals with expanding to RTL. All that code
- should be in cfgexpand.c. */
-#include "expr.h"
-
-
-
-/* Used to hold all the components required to do SSA PHI elimination.
- The node and pred/succ list is a simple linear list of nodes and
- edges represented as pairs of nodes.
-
- The predecessor and successor list: Nodes are entered in pairs, where
- [0] ->PRED, [1]->SUCC. All the even indexes in the array represent
- predecessors, all the odd elements are successors.
-
- Rationale:
- When implemented as bitmaps, very large programs SSA->Normal times were
- being dominated by clearing the interference graph.
-
- Typically this list of edges is extremely small since it only includes
- PHI results and uses from a single edge which have not coalesced with
- each other. This means that no virtual PHI nodes are included, and
- empirical evidence suggests that the number of edges rarely exceed
- 3, and in a bootstrap of GCC, the maximum size encountered was 7.
- This also limits the number of possible nodes that are involved to
- rarely more than 6, and in the bootstrap of gcc, the maximum number
- of nodes encountered was 12. */
-
-typedef struct _elim_graph {
- /* Size of the elimination vectors. */
- int size;
-
- /* List of nodes in the elimination graph. */
- vec<int> nodes;
-
- /* The predecessor and successor edge list. */
- vec<int> edge_list;
-
- /* Source locus on each edge */
- vec<source_location> edge_locus;
-
- /* Visited vector. */
- sbitmap visited;
-
- /* Stack for visited nodes. */
- vec<int> stack;
-
- /* The variable partition map. */
- var_map map;
-
- /* Edge being eliminated by this graph. */
- edge e;
-
- /* List of constant copies to emit. These are pushed on in pairs. */
- vec<int> const_dests;
- vec<tree> const_copies;
-
- /* Source locations for any constant copies. */
- vec<source_location> copy_locus;
-} *elim_graph;
-
-
-/* For an edge E find out a good source location to associate with
- instructions inserted on edge E. If E has an implicit goto set,
- use its location. Otherwise search instructions in predecessors
- of E for a location, and use that one. That makes sense because
- we insert on edges for PHI nodes, and effects of PHIs happen on
- the end of the predecessor conceptually. */
-
-static void
-set_location_for_edge (edge e)
-{
- if (e->goto_locus)
- {
- set_curr_insn_location (e->goto_locus);
- }
- else
- {
- basic_block bb = e->src;
- gimple_stmt_iterator gsi;
-
- do
- {
- for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi_prev (&gsi))
- {
- gimple stmt = gsi_stmt (gsi);
- if (is_gimple_debug (stmt))
- continue;
- if (gimple_has_location (stmt) || gimple_block (stmt))
- {
- set_curr_insn_location (gimple_location (stmt));
- return;
- }
- }
- /* Nothing found in this basic block. Make a half-assed attempt
- to continue with another block. */
- if (single_pred_p (bb))
- bb = single_pred (bb);
- else
- bb = e->src;
- }
- while (bb != e->src);
- }
-}
-
-/* Emit insns to copy SRC into DEST converting SRC if necessary. As
- SRC/DEST might be BLKmode memory locations SIZEEXP is a tree from
- which we deduce the size to copy in that case. */
-
-static inline rtx
-emit_partition_copy (rtx dest, rtx src, int unsignedsrcp, tree sizeexp)
-{
- rtx seq;
-
- start_sequence ();
-
- if (GET_MODE (src) != VOIDmode && GET_MODE (src) != GET_MODE (dest))
- src = convert_to_mode (GET_MODE (dest), src, unsignedsrcp);
- if (GET_MODE (src) == BLKmode)
- {
- gcc_assert (GET_MODE (dest) == BLKmode);
- emit_block_move (dest, src, expr_size (sizeexp), BLOCK_OP_NORMAL);
- }
- else
- emit_move_insn (dest, src);
-
- seq = get_insns ();
- end_sequence ();
-
- return seq;
-}
-
-/* Insert a copy instruction from partition SRC to DEST onto edge E. */
-
-static void
-insert_partition_copy_on_edge (edge e, int dest, int src, source_location locus)
-{
- tree var;
- rtx seq;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file,
- "Inserting a partition copy on edge BB%d->BB%d :"
- "PART.%d = PART.%d",
- e->src->index,
- e->dest->index, dest, src);
- fprintf (dump_file, "\n");
- }
-
- gcc_assert (SA.partition_to_pseudo[dest]);
- gcc_assert (SA.partition_to_pseudo[src]);
-
- set_location_for_edge (e);
- /* If a locus is provided, override the default. */
- if (locus)
- set_curr_insn_location (locus);
-
- var = partition_to_var (SA.map, src);
- seq = emit_partition_copy (SA.partition_to_pseudo[dest],
- SA.partition_to_pseudo[src],
- TYPE_UNSIGNED (TREE_TYPE (var)),
- var);
-
- insert_insn_on_edge (seq, e);
-}
-
-/* Insert a copy instruction from expression SRC to partition DEST
- onto edge E. */
-
-static void
-insert_value_copy_on_edge (edge e, int dest, tree src, source_location locus)
-{
- rtx seq, x;
- enum machine_mode dest_mode, src_mode;
- int unsignedp;
- tree var;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file,
- "Inserting a value copy on edge BB%d->BB%d : PART.%d = ",
- e->src->index,
- e->dest->index, dest);
- print_generic_expr (dump_file, src, TDF_SLIM);
- fprintf (dump_file, "\n");
- }
-
- gcc_assert (SA.partition_to_pseudo[dest]);
-
- set_location_for_edge (e);
- /* If a locus is provided, override the default. */
- if (locus)
- set_curr_insn_location (locus);
-
- start_sequence ();
-
- var = SSA_NAME_VAR (partition_to_var (SA.map, dest));
- src_mode = TYPE_MODE (TREE_TYPE (src));
- dest_mode = GET_MODE (SA.partition_to_pseudo[dest]);
- gcc_assert (src_mode == TYPE_MODE (TREE_TYPE (var)));
- gcc_assert (!REG_P (SA.partition_to_pseudo[dest])
- || dest_mode == promote_decl_mode (var, &unsignedp));
-
- if (src_mode != dest_mode)
- {
- x = expand_expr (src, NULL, src_mode, EXPAND_NORMAL);
- x = convert_modes (dest_mode, src_mode, x, unsignedp);
- }
- else if (src_mode == BLKmode)
- {
- x = SA.partition_to_pseudo[dest];
- store_expr (src, x, 0, false);
- }
- else
- x = expand_expr (src, SA.partition_to_pseudo[dest],
- dest_mode, EXPAND_NORMAL);
-
- if (x != SA.partition_to_pseudo[dest])
- emit_move_insn (SA.partition_to_pseudo[dest], x);
- seq = get_insns ();
- end_sequence ();
-
- insert_insn_on_edge (seq, e);
-}
-
-/* Insert a copy instruction from RTL expression SRC to partition DEST
- onto edge E. */
-
-static void
-insert_rtx_to_part_on_edge (edge e, int dest, rtx src, int unsignedsrcp,
- source_location locus)
-{
- rtx seq;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file,
- "Inserting a temp copy on edge BB%d->BB%d : PART.%d = ",
- e->src->index,
- e->dest->index, dest);
- print_simple_rtl (dump_file, src);
- fprintf (dump_file, "\n");
- }
-
- gcc_assert (SA.partition_to_pseudo[dest]);
-
- set_location_for_edge (e);
- /* If a locus is provided, override the default. */
- if (locus)
- set_curr_insn_location (locus);
-
- /* We give the destination as sizeexp in case src/dest are BLKmode
- mems. Usually we give the source. As we result from SSA names
- the left and right size should be the same (and no WITH_SIZE_EXPR
- involved), so it doesn't matter. */
- seq = emit_partition_copy (SA.partition_to_pseudo[dest],
- src, unsignedsrcp,
- partition_to_var (SA.map, dest));
-
- insert_insn_on_edge (seq, e);
-}
-
-/* Insert a copy instruction from partition SRC to RTL lvalue DEST
- onto edge E. */
-
-static void
-insert_part_to_rtx_on_edge (edge e, rtx dest, int src, source_location locus)
-{
- tree var;
- rtx seq;
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file,
- "Inserting a temp copy on edge BB%d->BB%d : ",
- e->src->index,
- e->dest->index);
- print_simple_rtl (dump_file, dest);
- fprintf (dump_file, "= PART.%d\n", src);
- }
-
- gcc_assert (SA.partition_to_pseudo[src]);
-
- set_location_for_edge (e);
- /* If a locus is provided, override the default. */
- if (locus)
- set_curr_insn_location (locus);
-
- var = partition_to_var (SA.map, src);
- seq = emit_partition_copy (dest,
- SA.partition_to_pseudo[src],
- TYPE_UNSIGNED (TREE_TYPE (var)),
- var);
-
- insert_insn_on_edge (seq, e);
-}
-
-
-/* Create an elimination graph with SIZE nodes and associated data
- structures. */
-
-static elim_graph
-new_elim_graph (int size)
-{
- elim_graph g = (elim_graph) xmalloc (sizeof (struct _elim_graph));
-
- g->nodes.create (30);
- g->const_dests.create (20);
- g->const_copies.create (20);
- g->copy_locus.create (10);
- g->edge_list.create (20);
- g->edge_locus.create (10);
- g->stack.create (30);
-
- g->visited = sbitmap_alloc (size);
-
- return g;
-}
-
-
-/* Empty elimination graph G. */
-
-static inline void
-clear_elim_graph (elim_graph g)
-{
- g->nodes.truncate (0);
- g->edge_list.truncate (0);
- g->edge_locus.truncate (0);
-}
-
-
-/* Delete elimination graph G. */
-
-static inline void
-delete_elim_graph (elim_graph g)
-{
- sbitmap_free (g->visited);
- g->stack.release ();
- g->edge_list.release ();
- g->const_copies.release ();
- g->const_dests.release ();
- g->nodes.release ();
- g->copy_locus.release ();
- g->edge_locus.release ();
-
- free (g);
-}
-
-
-/* Return the number of nodes in graph G. */
-
-static inline int
-elim_graph_size (elim_graph g)
-{
- return g->nodes.length ();
-}
-
-
-/* Add NODE to graph G, if it doesn't exist already. */
-
-static inline void
-elim_graph_add_node (elim_graph g, int node)
-{
- int x;
- int t;
-
- FOR_EACH_VEC_ELT (g->nodes, x, t)
- if (t == node)
- return;
- g->nodes.safe_push (node);
-}
-
-
-/* Add the edge PRED->SUCC to graph G. */
-
-static inline void
-elim_graph_add_edge (elim_graph g, int pred, int succ, source_location locus)
-{
- g->edge_list.safe_push (pred);
- g->edge_list.safe_push (succ);
- g->edge_locus.safe_push (locus);
-}
-
-
-/* Remove an edge from graph G for which NODE is the predecessor, and
- return the successor node. -1 is returned if there is no such edge. */
-
-static inline int
-elim_graph_remove_succ_edge (elim_graph g, int node, source_location *locus)
-{
- int y;
- unsigned x;
- for (x = 0; x < g->edge_list.length (); x += 2)
- if (g->edge_list[x] == node)
- {
- g->edge_list[x] = -1;
- y = g->edge_list[x + 1];
- g->edge_list[x + 1] = -1;
- *locus = g->edge_locus[x / 2];
- g->edge_locus[x / 2] = UNKNOWN_LOCATION;
- return y;
- }
- *locus = UNKNOWN_LOCATION;
- return -1;
-}
-
-
-/* Find all the nodes in GRAPH which are successors to NODE in the
- edge list. VAR will hold the partition number found. CODE is the
- code fragment executed for every node found. */
-
-#define FOR_EACH_ELIM_GRAPH_SUCC(GRAPH, NODE, VAR, LOCUS, CODE) \
-do { \
- unsigned x_; \
- int y_; \
- for (x_ = 0; x_ < (GRAPH)->edge_list.length (); x_ += 2) \
- { \
- y_ = (GRAPH)->edge_list[x_]; \
- if (y_ != (NODE)) \
- continue; \
- (void) ((VAR) = (GRAPH)->edge_list[x_ + 1]); \
- (void) ((LOCUS) = (GRAPH)->edge_locus[x_ / 2]); \
- CODE; \
- } \
-} while (0)
-
-
-/* Find all the nodes which are predecessors of NODE in the edge list for
- GRAPH. VAR will hold the partition number found. CODE is the
- code fragment executed for every node found. */
-
-#define FOR_EACH_ELIM_GRAPH_PRED(GRAPH, NODE, VAR, LOCUS, CODE) \
-do { \
- unsigned x_; \
- int y_; \
- for (x_ = 0; x_ < (GRAPH)->edge_list.length (); x_ += 2) \
- { \
- y_ = (GRAPH)->edge_list[x_ + 1]; \
- if (y_ != (NODE)) \
- continue; \
- (void) ((VAR) = (GRAPH)->edge_list[x_]); \
- (void) ((LOCUS) = (GRAPH)->edge_locus[x_ / 2]); \
- CODE; \
- } \
-} while (0)
-
-
-/* Add T to elimination graph G. */
-
-static inline void
-eliminate_name (elim_graph g, int T)
-{
- elim_graph_add_node (g, T);
-}
-
-
-/* Build elimination graph G for basic block BB on incoming PHI edge
- G->e. */
-
-static void
-eliminate_build (elim_graph g)
-{
- tree Ti;
- int p0, pi;
- gimple_stmt_iterator gsi;
-
- clear_elim_graph (g);
-
- for (gsi = gsi_start_phis (g->e->dest); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple phi = gsi_stmt (gsi);
- source_location locus;
-
- p0 = var_to_partition (g->map, gimple_phi_result (phi));
- /* Ignore results which are not in partitions. */
- if (p0 == NO_PARTITION)
- continue;
-
- Ti = PHI_ARG_DEF (phi, g->e->dest_idx);
- locus = gimple_phi_arg_location_from_edge (phi, g->e);
-
- /* If this argument is a constant, or a SSA_NAME which is being
- left in SSA form, just queue a copy to be emitted on this
- edge. */
- if (!phi_ssa_name_p (Ti)
- || (TREE_CODE (Ti) == SSA_NAME
- && var_to_partition (g->map, Ti) == NO_PARTITION))
- {
- /* Save constant copies until all other copies have been emitted
- on this edge. */
- g->const_dests.safe_push (p0);
- g->const_copies.safe_push (Ti);
- g->copy_locus.safe_push (locus);
- }
- else
- {
- pi = var_to_partition (g->map, Ti);
- if (p0 != pi)
- {
- eliminate_name (g, p0);
- eliminate_name (g, pi);
- elim_graph_add_edge (g, p0, pi, locus);
- }
- }
- }
-}
-
-
-/* Push successors of T onto the elimination stack for G. */
-
-static void
-elim_forward (elim_graph g, int T)
-{
- int S;
- source_location locus;
-
- bitmap_set_bit (g->visited, T);
- FOR_EACH_ELIM_GRAPH_SUCC (g, T, S, locus,
- {
- if (!bitmap_bit_p (g->visited, S))
- elim_forward (g, S);
- });
- g->stack.safe_push (T);
-}
-
-
-/* Return 1 if there unvisited predecessors of T in graph G. */
-
-static int
-elim_unvisited_predecessor (elim_graph g, int T)
-{
- int P;
- source_location locus;
-
- FOR_EACH_ELIM_GRAPH_PRED (g, T, P, locus,
- {
- if (!bitmap_bit_p (g->visited, P))
- return 1;
- });
- return 0;
-}
-
-/* Process predecessors first, and insert a copy. */
-
-static void
-elim_backward (elim_graph g, int T)
-{
- int P;
- source_location locus;
-
- bitmap_set_bit (g->visited, T);
- FOR_EACH_ELIM_GRAPH_PRED (g, T, P, locus,
- {
- if (!bitmap_bit_p (g->visited, P))
- {
- elim_backward (g, P);
- insert_partition_copy_on_edge (g->e, P, T, locus);
- }
- });
-}
-
-/* Allocate a new pseudo register usable for storing values sitting
- in NAME (a decl or SSA name), i.e. with matching mode and attributes. */
-
-static rtx
-get_temp_reg (tree name)
-{
- tree var = TREE_CODE (name) == SSA_NAME ? SSA_NAME_VAR (name) : name;
- tree type = TREE_TYPE (var);
- int unsignedp;
- enum machine_mode reg_mode = promote_decl_mode (var, &unsignedp);
- rtx x = gen_reg_rtx (reg_mode);
- if (POINTER_TYPE_P (type))
- mark_reg_pointer (x, TYPE_ALIGN (TREE_TYPE (TREE_TYPE (var))));
- return x;
-}
-
-/* Insert required copies for T in graph G. Check for a strongly connected
- region, and create a temporary to break the cycle if one is found. */
-
-static void
-elim_create (elim_graph g, int T)
-{
- int P, S;
- source_location locus;
-
- if (elim_unvisited_predecessor (g, T))
- {
- tree var = partition_to_var (g->map, T);
- rtx U = get_temp_reg (var);
- int unsignedsrcp = TYPE_UNSIGNED (TREE_TYPE (var));
-
- insert_part_to_rtx_on_edge (g->e, U, T, UNKNOWN_LOCATION);
- FOR_EACH_ELIM_GRAPH_PRED (g, T, P, locus,
- {
- if (!bitmap_bit_p (g->visited, P))
- {
- elim_backward (g, P);
- insert_rtx_to_part_on_edge (g->e, P, U, unsignedsrcp, locus);
- }
- });
- }
- else
- {
- S = elim_graph_remove_succ_edge (g, T, &locus);
- if (S != -1)
- {
- bitmap_set_bit (g->visited, T);
- insert_partition_copy_on_edge (g->e, T, S, locus);
- }
- }
-}
-
-
-/* Eliminate all the phi nodes on edge E in graph G. */
-
-static void
-eliminate_phi (edge e, elim_graph g)
-{
- int x;
-
- gcc_assert (g->const_copies.length () == 0);
- gcc_assert (g->copy_locus.length () == 0);
-
- /* Abnormal edges already have everything coalesced. */
- if (e->flags & EDGE_ABNORMAL)
- return;
-
- g->e = e;
-
- eliminate_build (g);
-
- if (elim_graph_size (g) != 0)
- {
- int part;
-
- bitmap_clear (g->visited);
- g->stack.truncate (0);
-
- FOR_EACH_VEC_ELT (g->nodes, x, part)
- {
- if (!bitmap_bit_p (g->visited, part))
- elim_forward (g, part);
- }
-
- bitmap_clear (g->visited);
- while (g->stack.length () > 0)
- {
- x = g->stack.pop ();
- if (!bitmap_bit_p (g->visited, x))
- elim_create (g, x);
- }
- }
-
- /* If there are any pending constant copies, issue them now. */
- while (g->const_copies.length () > 0)
- {
- int dest;
- tree src;
- source_location locus;
-
- src = g->const_copies.pop ();
- dest = g->const_dests.pop ();
- locus = g->copy_locus.pop ();
- insert_value_copy_on_edge (e, dest, src, locus);
- }
-}
-
-
-/* Remove each argument from PHI. If an arg was the last use of an SSA_NAME,
- check to see if this allows another PHI node to be removed. */
-
-static void
-remove_gimple_phi_args (gimple phi)
-{
- use_operand_p arg_p;
- ssa_op_iter iter;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "Removing Dead PHI definition: ");
- print_gimple_stmt (dump_file, phi, 0, TDF_SLIM);
- }
-
- FOR_EACH_PHI_ARG (arg_p, phi, iter, SSA_OP_USE)
- {
- tree arg = USE_FROM_PTR (arg_p);
- if (TREE_CODE (arg) == SSA_NAME)
- {
- /* Remove the reference to the existing argument. */
- SET_USE (arg_p, NULL_TREE);
- if (has_zero_uses (arg))
- {
- gimple stmt;
- gimple_stmt_iterator gsi;
-
- stmt = SSA_NAME_DEF_STMT (arg);
-
- /* Also remove the def if it is a PHI node. */
- if (gimple_code (stmt) == GIMPLE_PHI)
- {
- remove_gimple_phi_args (stmt);
- gsi = gsi_for_stmt (stmt);
- remove_phi_node (&gsi, true);
- }
-
- }
- }
- }
-}
-
-/* Remove any PHI node which is a virtual PHI, or a PHI with no uses. */
-
-static void
-eliminate_useless_phis (void)
-{
- basic_block bb;
- gimple_stmt_iterator gsi;
- tree result;
-
- FOR_EACH_BB (bb)
- {
- for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
- {
- gimple phi = gsi_stmt (gsi);
- result = gimple_phi_result (phi);
- if (virtual_operand_p (result))
- {
-#ifdef ENABLE_CHECKING
- size_t i;
- /* There should be no arguments which are not virtual, or the
- results will be incorrect. */
- for (i = 0; i < gimple_phi_num_args (phi); i++)
- {
- tree arg = PHI_ARG_DEF (phi, i);
- if (TREE_CODE (arg) == SSA_NAME
- && !virtual_operand_p (arg))
- {
- fprintf (stderr, "Argument of PHI is not virtual (");
- print_generic_expr (stderr, arg, TDF_SLIM);
- fprintf (stderr, "), but the result is :");
- print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
- internal_error ("SSA corruption");
- }
- }
-#endif
- remove_phi_node (&gsi, true);
- }
- else
- {
- /* Also remove real PHIs with no uses. */
- if (has_zero_uses (result))
- {
- remove_gimple_phi_args (phi);
- remove_phi_node (&gsi, true);
- }
- else
- gsi_next (&gsi);
- }
- }
- }
-}
-
-
-/* This function will rewrite the current program using the variable mapping
- found in MAP. If the replacement vector VALUES is provided, any
- occurrences of partitions with non-null entries in the vector will be
- replaced with the expression in the vector instead of its mapped
- variable. */
-
-static void
-rewrite_trees (var_map map ATTRIBUTE_UNUSED)
-{
-#ifdef ENABLE_CHECKING
- basic_block bb;
- /* Search for PHIs where the destination has no partition, but one
- or more arguments has a partition. This should not happen and can
- create incorrect code. */
- FOR_EACH_BB (bb)
- {
- gimple_stmt_iterator gsi;
- for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple phi = gsi_stmt (gsi);
- tree T0 = var_to_partition_to_var (map, gimple_phi_result (phi));
- if (T0 == NULL_TREE)
- {
- size_t i;
- for (i = 0; i < gimple_phi_num_args (phi); i++)
- {
- tree arg = PHI_ARG_DEF (phi, i);
-
- if (TREE_CODE (arg) == SSA_NAME
- && var_to_partition (map, arg) != NO_PARTITION)
- {
- fprintf (stderr, "Argument of PHI is in a partition :(");
- print_generic_expr (stderr, arg, TDF_SLIM);
- fprintf (stderr, "), but the result is not :");
- print_gimple_stmt (stderr, phi, 0, TDF_SLIM);
- internal_error ("SSA corruption");
- }
- }
- }
- }
- }
-#endif
-}
-
-/* Given the out-of-ssa info object SA (with prepared partitions)
- eliminate all phi nodes in all basic blocks. Afterwards no
- basic block will have phi nodes anymore and there are possibly
- some RTL instructions inserted on edges. */
-
-void
-expand_phi_nodes (struct ssaexpand *sa)
-{
- basic_block bb;
- elim_graph g = new_elim_graph (sa->map->num_partitions);
- g->map = sa->map;
-
- FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR->next_bb, EXIT_BLOCK_PTR, next_bb)
- if (!gimple_seq_empty_p (phi_nodes (bb)))
- {
- edge e;
- edge_iterator ei;
- FOR_EACH_EDGE (e, ei, bb->preds)
- eliminate_phi (e, g);
- set_phi_nodes (bb, NULL);
- /* We can't redirect EH edges in RTL land, so we need to do this
- here. Redirection happens only when splitting is necessary,
- which it is only for critical edges, normally. For EH edges
- it might also be necessary when the successor has more than
- one predecessor. In that case the edge is either required to
- be fallthru (which EH edges aren't), or the predecessor needs
- to end with a jump (which again, isn't the case with EH edges).
- Hence, split all EH edges on which we inserted instructions
- and whose successor has multiple predecessors. */
- for (ei = ei_start (bb->preds); (e = ei_safe_edge (ei)); )
- {
- if (e->insns.r && (e->flags & EDGE_EH)
- && !single_pred_p (e->dest))
- {
- rtx insns = e->insns.r;
- basic_block bb;
- e->insns.r = NULL_RTX;
- bb = split_edge (e);
- single_pred_edge (bb)->insns.r = insns;
- }
- else
- ei_next (&ei);
- }
- }
-
- delete_elim_graph (g);
-}
-
-
-/* Remove the ssa-names in the current function and translate them into normal
- compiler variables. PERFORM_TER is true if Temporary Expression Replacement
- should also be used. */
-
-static void
-remove_ssa_form (bool perform_ter, struct ssaexpand *sa)
-{
- bitmap values = NULL;
- var_map map;
- unsigned i;
-
- map = coalesce_ssa_name ();
-
- /* Return to viewing the variable list as just all reference variables after
- coalescing has been performed. */
- partition_view_normal (map, false);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, "After Coalescing:\n");
- dump_var_map (dump_file, map);
- }
-
- if (perform_ter)
- {
- values = find_replaceable_exprs (map);
- if (values && dump_file && (dump_flags & TDF_DETAILS))
- dump_replaceable_exprs (dump_file, values);
- }
-
- rewrite_trees (map);
-
- sa->map = map;
- sa->values = values;
- sa->partition_has_default_def = BITMAP_ALLOC (NULL);
- for (i = 1; i < num_ssa_names; i++)
- {
- tree t = ssa_name (i);
- if (t && SSA_NAME_IS_DEFAULT_DEF (t))
- {
- int p = var_to_partition (map, t);
- if (p != NO_PARTITION)
- bitmap_set_bit (sa->partition_has_default_def, p);
- }
- }
-}
-
-
-/* If not already done so for basic block BB, assign increasing uids
- to each of its instructions. */
-
-static void
-maybe_renumber_stmts_bb (basic_block bb)
-{
- unsigned i = 0;
- gimple_stmt_iterator gsi;
-
- if (!bb->aux)
- return;
- bb->aux = NULL;
- for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple stmt = gsi_stmt (gsi);
- gimple_set_uid (stmt, i);
- i++;
- }
-}
-
-
-/* Return true if we can determine that the SSA_NAMEs RESULT (a result
- of a PHI node) and ARG (one of its arguments) conflict. Return false
- otherwise, also when we simply aren't sure. */
-
-static bool
-trivially_conflicts_p (basic_block bb, tree result, tree arg)
-{
- use_operand_p use;
- imm_use_iterator imm_iter;
- gimple defa = SSA_NAME_DEF_STMT (arg);
-
- /* If ARG isn't defined in the same block it's too complicated for
- our little mind. */
- if (gimple_bb (defa) != bb)
- return false;
-
- FOR_EACH_IMM_USE_FAST (use, imm_iter, result)
- {
- gimple use_stmt = USE_STMT (use);
- if (is_gimple_debug (use_stmt))
- continue;
- /* Now, if there's a use of RESULT that lies outside this basic block,
- then there surely is a conflict with ARG. */
- if (gimple_bb (use_stmt) != bb)
- return true;
- if (gimple_code (use_stmt) == GIMPLE_PHI)
- continue;
- /* The use now is in a real stmt of BB, so if ARG was defined
- in a PHI node (like RESULT) both conflict. */
- if (gimple_code (defa) == GIMPLE_PHI)
- return true;
- maybe_renumber_stmts_bb (bb);
- /* If the use of RESULT occurs after the definition of ARG,
- the two conflict too. */
- if (gimple_uid (defa) < gimple_uid (use_stmt))
- return true;
- }
-
- return false;
-}
-
-
-/* Search every PHI node for arguments associated with backedges which
- we can trivially determine will need a copy (the argument is either
- not an SSA_NAME or the argument has a different underlying variable
- than the PHI result).
-
- Insert a copy from the PHI argument to a new destination at the
- end of the block with the backedge to the top of the loop. Update
- the PHI argument to reference this new destination. */
-
-static void
-insert_backedge_copies (void)
-{
- basic_block bb;
- gimple_stmt_iterator gsi;
-
- mark_dfs_back_edges ();
-
- FOR_EACH_BB (bb)
- {
- /* Mark block as possibly needing calculation of UIDs. */
- bb->aux = &bb->aux;
-
- for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
- {
- gimple phi = gsi_stmt (gsi);
- tree result = gimple_phi_result (phi);
- size_t i;
-
- if (virtual_operand_p (result))
- continue;
-
- for (i = 0; i < gimple_phi_num_args (phi); i++)
- {
- tree arg = gimple_phi_arg_def (phi, i);
- edge e = gimple_phi_arg_edge (phi, i);
-
- /* If the argument is not an SSA_NAME, then we will need a
- constant initialization. If the argument is an SSA_NAME with
- a different underlying variable then a copy statement will be
- needed. */
- if ((e->flags & EDGE_DFS_BACK)
- && (TREE_CODE (arg) != SSA_NAME
- || SSA_NAME_VAR (arg) != SSA_NAME_VAR (result)
- || trivially_conflicts_p (bb, result, arg)))
- {
- tree name;
- gimple stmt, last = NULL;
- gimple_stmt_iterator gsi2;
-
- gsi2 = gsi_last_bb (gimple_phi_arg_edge (phi, i)->src);
- if (!gsi_end_p (gsi2))
- last = gsi_stmt (gsi2);
-
- /* In theory the only way we ought to get back to the
- start of a loop should be with a COND_EXPR or GOTO_EXPR.
- However, better safe than sorry.
- If the block ends with a control statement or
- something that might throw, then we have to
- insert this assignment before the last
- statement. Else insert it after the last statement. */
- if (last && stmt_ends_bb_p (last))
- {
- /* If the last statement in the block is the definition
- site of the PHI argument, then we can't insert
- anything after it. */
- if (TREE_CODE (arg) == SSA_NAME
- && SSA_NAME_DEF_STMT (arg) == last)
- continue;
- }
-
- /* Create a new instance of the underlying variable of the
- PHI result. */
- name = copy_ssa_name (result, NULL);
- stmt = gimple_build_assign (name,
- gimple_phi_arg_def (phi, i));
-
- /* copy location if present. */
- if (gimple_phi_arg_has_location (phi, i))
- gimple_set_location (stmt,
- gimple_phi_arg_location (phi, i));
-
- /* Insert the new statement into the block and update
- the PHI node. */
- if (last && stmt_ends_bb_p (last))
- gsi_insert_before (&gsi2, stmt, GSI_NEW_STMT);
- else
- gsi_insert_after (&gsi2, stmt, GSI_NEW_STMT);
- SET_PHI_ARG_DEF (phi, i, name);
- }
- }
- }
-
- /* Unmark this block again. */
- bb->aux = NULL;
- }
-}
-
-/* Free all memory associated with going out of SSA form. SA is
- the outof-SSA info object. */
-
-void
-finish_out_of_ssa (struct ssaexpand *sa)
-{
- free (sa->partition_to_pseudo);
- if (sa->values)
- BITMAP_FREE (sa->values);
- delete_var_map (sa->map);
- BITMAP_FREE (sa->partition_has_default_def);
- memset (sa, 0, sizeof *sa);
-}
-
-/* Take the current function out of SSA form, translating PHIs as described in
- R. Morgan, ``Building an Optimizing Compiler'',
- Butterworth-Heinemann, Boston, MA, 1998. pp 176-186. */
-
-unsigned int
-rewrite_out_of_ssa (struct ssaexpand *sa)
-{
- /* If elimination of a PHI requires inserting a copy on a backedge,
- then we will have to split the backedge which has numerous
- undesirable performance effects.
-
- A significant number of such cases can be handled here by inserting
- copies into the loop itself. */
- insert_backedge_copies ();
-
-
- /* Eliminate PHIs which are of no use, such as virtual or dead phis. */
- eliminate_useless_phis ();
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
-
- remove_ssa_form (flag_tree_ter, sa);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- gimple_dump_cfg (dump_file, dump_flags & ~TDF_DETAILS);
-
- return 0;
-}
