+2009-06-07 Paolo Bonzini <bonzini@gnu.org>
+
+ PR rtl-optimization/26854
+ * timevar.def: Remove TV_DF_RU, add TV_DF_MD.
+ * df-problems.c (df_rd_add_problem): Fix comment.
+ (df_md_set_bb_info, df_md_free_bb_info, df_md_alloc,
+ df_md_simulate_artificial_defs_at_top,
+ df_md_simulate_one_insn, df_md_bb_local_compute_process_def,
+ df_md_bb_local_compute, df_md_local_compute, df_md_reset,
+ df_md_transfer_function, df_md_init, df_md_confluence_0,
+ df_md_confluence_n, df_md_free, df_md_top_dump, df_md_bottom_dump,
+ problem_MD, df_md_add_problem): New.
+ * df.h (DF_MD, DF_MD_BB_INFO, struct df_md_bb_info, df_md,
+ df_md_get_bb_info): New.
+ DF_LAST_PROBLEM_PLUS1): Adjust.
+
+ * Makefile.in (fwprop.o): Include domwalk.h.
+ * fwprop.c: Include domwalk.h.
+ (reg_defs, reg_defs_stack): New.
+ (bitmap_only_bit_between): Remove.
+ (process_defs): New.
+ (process_uses): Use reg_defs and local_md instead of
+ bitmap_only_bit_between and local_rd.
+ (single_def_use_enter_block): New, from build_single_def_use_links.
+ (single_def_use_leave_block): New.
+ (build_single_def_use_links): Remove code moved to
+ single_def_use_enter_block, invoke domwalk.
+ (use_killed_between): Adjust comment.
+
2009-06-27 Paolo Bonzini <bonzini@gnu.org>
* bitmap.h (bitmap_ior_and_into): New.
fwprop.o : fwprop.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
$(TOPLEV_H) insn-config.h $(RECOG_H) $(FLAGS_H) $(OBSTACK_H) $(BASIC_BLOCK_H) \
output.h $(DF_H) alloc-pool.h $(TIMEVAR_H) $(TREE_PASS_H) $(TARGET_H) \
- $(TM_P_H) $(CFGLOOP_H) $(EMIT_RTL_H)
+ $(TM_P_H) $(CFGLOOP_H) $(EMIT_RTL_H) domwalk.h
web.o : web.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(RTL_H) \
hard-reg-set.h $(FLAGS_H) $(BASIC_BLOCK_H) $(FUNCTION_H) output.h $(TOPLEV_H) \
$(DF_H) $(OBSTACK_H) $(TIMEVAR_H) $(TREE_PASS_H)
-/* Create a new DATAFLOW instance and add it to an existing instance
- of DF. The returned structure is what is used to get at the
- solution. */
+/* Create a new RD instance and add it to the existing instance
+ of DF. */
void
df_rd_add_problem (void)
bitmap_clear_bit (live, DF_REF_REGNO (def));
}
}
+
+
+\f
+/*----------------------------------------------------------------------------
+ MULTIPLE DEFINITIONS
+
+ Find the locations in the function reached by multiple definition sites
+ for a pseudo. In and out bitvectors are built for each basic
+ block.
+
+ The gen and kill sets for the problem are obvious. Together they
+ include all defined registers in a basic block; the gen set includes
+ registers where a partial or conditional or may-clobber definition is
+ last in the BB, while the kill set includes registers with a complete
+ definition coming last. However, the computation of the dataflow
+ itself is interesting.
+
+ The idea behind it comes from SSA form's iterated dominance frontier
+ criterion for inserting PHI functions. Just like in that case, we can use
+ the dominance frontier to find places where multiple definitions meet;
+ a register X defined in a basic block BB1 has multiple definitions in
+ basic blocks in BB1's dominance frontier.
+
+ So, the in-set of a basic block BB2 is not just the union of the
+ out-sets of BB2's predecessors, but includes some more bits that come
+ from the basic blocks of whose dominance frontier BB2 is part (BB1 in
+ the previous paragraph). I called this set the init-set of BB2.
+
+ (Note: I actually use the kill-set only to build the init-set.
+ gen bits are anyway propagated from BB1 to BB2 by dataflow).
+
+ For example, if you have
+
+ BB1 : r10 = 0
+ r11 = 0
+ if <...> goto BB2 else goto BB3;
+
+ BB2 : r10 = 1
+ r12 = 1
+ goto BB3;
+
+ BB3 :
+
+ you have BB3 in BB2's dominance frontier but not in BB1's, so that the
+ init-set of BB3 includes r10 and r12, but not r11. Note that we do
+ not need to iterate the dominance frontier, because we do not insert
+ anything like PHI functions there! Instead, dataflow will take care of
+ propagating the information to BB3's successors.
+ ---------------------------------------------------------------------------*/
+
+/* Set basic block info. */
+
+static void
+df_md_set_bb_info (unsigned int index,
+ struct df_md_bb_info *bb_info)
+{
+ gcc_assert (df_md);
+ gcc_assert (index < df_md->block_info_size);
+ df_md->block_info[index] = bb_info;
+}
+
+
+static void
+df_md_free_bb_info (basic_block bb ATTRIBUTE_UNUSED,
+ void *vbb_info)
+{
+ struct df_md_bb_info *bb_info = (struct df_md_bb_info *) vbb_info;
+ if (bb_info)
+ {
+ BITMAP_FREE (bb_info->kill);
+ BITMAP_FREE (bb_info->gen);
+ BITMAP_FREE (bb_info->init);
+ BITMAP_FREE (bb_info->in);
+ BITMAP_FREE (bb_info->out);
+ pool_free (df_md->block_pool, bb_info);
+ }
+}
+
+
+/* Allocate or reset bitmaps for DF_MD. The solution bits are
+ not touched unless the block is new. */
+
+static void
+df_md_alloc (bitmap all_blocks)
+{
+ unsigned int bb_index;
+ bitmap_iterator bi;
+
+ if (!df_md->block_pool)
+ df_md->block_pool = create_alloc_pool ("df_md_block pool",
+ sizeof (struct df_md_bb_info), 50);
+
+ df_grow_bb_info (df_md);
+
+ EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+ {
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+ if (bb_info)
+ {
+ bitmap_clear (bb_info->init);
+ bitmap_clear (bb_info->gen);
+ bitmap_clear (bb_info->kill);
+ bitmap_clear (bb_info->in);
+ bitmap_clear (bb_info->out);
+ }
+ else
+ {
+ bb_info = (struct df_md_bb_info *) pool_alloc (df_md->block_pool);
+ df_md_set_bb_info (bb_index, bb_info);
+ bb_info->init = BITMAP_ALLOC (NULL);
+ bb_info->gen = BITMAP_ALLOC (NULL);
+ bb_info->kill = BITMAP_ALLOC (NULL);
+ bb_info->in = BITMAP_ALLOC (NULL);
+ bb_info->out = BITMAP_ALLOC (NULL);
+ }
+ }
+
+ df_md->optional_p = true;
+}
+
+/* Add the effect of the top artificial defs of BB to the multiple definitions
+ bitmap LOCAL_MD. */
+
+void
+df_md_simulate_artificial_defs_at_top (basic_block bb, bitmap local_md)
+{
+ int bb_index = bb->index;
+ df_ref *def_rec;
+ for (def_rec = df_get_artificial_defs (bb_index); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ if (DF_REF_FLAGS (def) & DF_REF_AT_TOP)
+ {
+ unsigned int dregno = DF_REF_REGNO (def);
+ if (DF_REF_FLAGS (def)
+ & (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))
+ bitmap_set_bit (local_md, dregno);
+ else
+ bitmap_clear_bit (local_md, dregno);
+ }
+ }
+}
+
+
+/* Add the effect of the defs of INSN to the reaching definitions bitmap
+ LOCAL_MD. */
+
+void
+df_md_simulate_one_insn (basic_block bb ATTRIBUTE_UNUSED, rtx insn,
+ bitmap local_md)
+{
+ unsigned uid = INSN_UID (insn);
+ df_ref *def_rec;
+
+ for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
+ {
+ df_ref def = *def_rec;
+ unsigned int dregno = DF_REF_REGNO (def);
+ if ((!(df->changeable_flags & DF_NO_HARD_REGS))
+ || (dregno >= FIRST_PSEUDO_REGISTER))
+ {
+ if (DF_REF_FLAGS (def)
+ & (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))
+ bitmap_set_bit (local_md, DF_REF_ID (def));
+ else
+ bitmap_clear_bit (local_md, DF_REF_ID (def));
+ }
+ }
+}
+
+static void
+df_md_bb_local_compute_process_def (struct df_md_bb_info *bb_info,
+ df_ref *def_rec,
+ int top_flag)
+{
+ df_ref def;
+ bitmap_clear (seen_in_insn);
+
+ while ((def = *def_rec++) != NULL)
+ {
+ unsigned int dregno = DF_REF_REGNO (def);
+ if (((!(df->changeable_flags & DF_NO_HARD_REGS))
+ || (dregno >= FIRST_PSEUDO_REGISTER))
+ && top_flag == (DF_REF_FLAGS (def) & DF_REF_AT_TOP))
+ {
+ if (!bitmap_bit_p (seen_in_insn, dregno))
+ {
+ if (DF_REF_FLAGS (def)
+ & (DF_REF_PARTIAL | DF_REF_CONDITIONAL | DF_REF_MAY_CLOBBER))
+ {
+ bitmap_set_bit (bb_info->gen, dregno);
+ bitmap_clear_bit (bb_info->kill, dregno);
+ }
+ else
+ {
+ /* When we find a clobber and a regular def,
+ make sure the regular def wins. */
+ bitmap_set_bit (seen_in_insn, dregno);
+ bitmap_set_bit (bb_info->kill, dregno);
+ bitmap_clear_bit (bb_info->gen, dregno);
+ }
+ }
+ }
+ }
+}
+
+
+/* Compute local multiple def info for basic block BB. */
+
+static void
+df_md_bb_local_compute (unsigned int bb_index)
+{
+ basic_block bb = BASIC_BLOCK (bb_index);
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+ rtx insn;
+
+ /* Artificials are only hard regs. */
+ if (!(df->changeable_flags & DF_NO_HARD_REGS))
+ df_md_bb_local_compute_process_def (bb_info,
+ df_get_artificial_defs (bb_index),
+ DF_REF_AT_TOP);
+
+ FOR_BB_INSNS (bb, insn)
+ {
+ unsigned int uid = INSN_UID (insn);
+ if (!INSN_P (insn))
+ continue;
+
+ df_md_bb_local_compute_process_def (bb_info, DF_INSN_UID_DEFS (uid), 0);
+ }
+
+ if (!(df->changeable_flags & DF_NO_HARD_REGS))
+ df_md_bb_local_compute_process_def (bb_info,
+ df_get_artificial_defs (bb_index),
+ 0);
+}
+
+/* Compute local reaching def info for each basic block within BLOCKS. */
+
+static void
+df_md_local_compute (bitmap all_blocks)
+{
+ unsigned int bb_index, df_bb_index;
+ bitmap_iterator bi1, bi2;
+ basic_block bb;
+ bitmap *frontiers;
+
+ df_set_seen ();
+
+ EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi1)
+ {
+ df_md_bb_local_compute (bb_index);
+ }
+
+ df_unset_seen ();
+
+ frontiers = XNEWVEC (bitmap, last_basic_block);
+ FOR_ALL_BB (bb)
+ frontiers[bb->index] = BITMAP_ALLOC (NULL);
+
+ compute_dominance_frontiers (frontiers);
+
+ /* Add each basic block's kills to the nodes in the frontier of the BB. */
+ EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi1)
+ {
+ bitmap kill = df_md_get_bb_info (bb_index)->kill;
+ EXECUTE_IF_SET_IN_BITMAP (frontiers[bb_index], 0, df_bb_index, bi2)
+ {
+ if (bitmap_bit_p (all_blocks, df_bb_index))
+ bitmap_ior_into (df_md_get_bb_info (df_bb_index)->init, kill);
+ }
+ }
+
+ FOR_ALL_BB (bb)
+ BITMAP_FREE (frontiers[bb->index]);
+ free (frontiers);
+}
+
+
+/* Reset the global solution for recalculation. */
+
+static void
+df_md_reset (bitmap all_blocks)
+{
+ unsigned int bb_index;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+ {
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+ gcc_assert (bb_info);
+ bitmap_clear (bb_info->in);
+ bitmap_clear (bb_info->out);
+ }
+}
+
+static bool
+df_md_transfer_function (int bb_index)
+{
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+ bitmap in = bb_info->in;
+ bitmap out = bb_info->out;
+ bitmap gen = bb_info->gen;
+ bitmap kill = bb_info->kill;
+
+ return bitmap_ior_and_compl (out, gen, in, kill);
+}
+
+/* Initialize the solution bit vectors for problem. */
+
+static void
+df_md_init (bitmap all_blocks)
+{
+ unsigned int bb_index;
+ bitmap_iterator bi;
+
+ EXECUTE_IF_SET_IN_BITMAP (all_blocks, 0, bb_index, bi)
+ {
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb_index);
+
+ bitmap_copy (bb_info->in, bb_info->init);
+ df_md_transfer_function (bb_index);
+ }
+}
+
+static void
+df_md_confluence_0 (basic_block bb)
+{
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+ bitmap_copy (bb_info->in, bb_info->init);
+}
+
+/* In of target gets or of out of source. */
+
+static void
+df_md_confluence_n (edge e)
+{
+ bitmap op1 = df_md_get_bb_info (e->dest->index)->in;
+ bitmap op2 = df_md_get_bb_info (e->src->index)->out;
+
+ if (e->flags & EDGE_FAKE)
+ return;
+
+ if (e->flags & EDGE_EH)
+ bitmap_ior_and_compl_into (op1, op2, regs_invalidated_by_call_regset);
+ else
+ bitmap_ior_into (op1, op2);
+}
+
+/* Free all storage associated with the problem. */
+
+static void
+df_md_free (void)
+{
+ unsigned int i;
+ for (i = 0; i < df_md->block_info_size; i++)
+ {
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (i);
+ if (bb_info)
+ {
+ BITMAP_FREE (bb_info->kill);
+ BITMAP_FREE (bb_info->gen);
+ BITMAP_FREE (bb_info->init);
+ BITMAP_FREE (bb_info->in);
+ BITMAP_FREE (bb_info->out);
+ }
+ }
+
+ free_alloc_pool (df_md->block_pool);
+
+ df_md->block_info_size = 0;
+ free (df_md->block_info);
+ free (df_md);
+}
+
+
+/* Debugging info at top of bb. */
+
+static void
+df_md_top_dump (basic_block bb, FILE *file)
+{
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+ if (!bb_info || !bb_info->in)
+ return;
+
+ fprintf (file, ";; md in \t");
+ df_print_regset (file, bb_info->in);
+ fprintf (file, ";; md init \t");
+ df_print_regset (file, bb_info->init);
+ fprintf (file, ";; md gen \t");
+ df_print_regset (file, bb_info->gen);
+ fprintf (file, ";; md kill \t");
+ df_print_regset (file, bb_info->kill);
+}
+
+/* Debugging info at bottom of bb. */
+
+static void
+df_md_bottom_dump (basic_block bb, FILE *file)
+{
+ struct df_md_bb_info *bb_info = df_md_get_bb_info (bb->index);
+ if (!bb_info || !bb_info->out)
+ return;
+
+ fprintf (file, ";; md out \t");
+ df_print_regset (file, bb_info->out);
+}
+
+static struct df_problem problem_MD =
+{
+ DF_MD, /* Problem id. */
+ DF_FORWARD, /* Direction. */
+ df_md_alloc, /* Allocate the problem specific data. */
+ df_md_reset, /* Reset global information. */
+ df_md_free_bb_info, /* Free basic block info. */
+ df_md_local_compute, /* Local compute function. */
+ df_md_init, /* Init the solution specific data. */
+ df_worklist_dataflow, /* Worklist solver. */
+ df_md_confluence_0, /* Confluence operator 0. */
+ df_md_confluence_n, /* Confluence operator n. */
+ df_md_transfer_function, /* Transfer function. */
+ NULL, /* Finalize function. */
+ df_md_free, /* Free all of the problem information. */
+ df_md_free, /* Remove this problem from the stack of dataflow problems. */
+ NULL, /* Debugging. */
+ df_md_top_dump, /* Debugging start block. */
+ df_md_bottom_dump, /* Debugging end block. */
+ NULL, /* Incremental solution verify start. */
+ NULL, /* Incremental solution verify end. */
+ NULL, /* Dependent problem. */
+ TV_DF_MD, /* Timing variable. */
+ false /* Reset blocks on dropping out of blocks_to_analyze. */
+};
+
+/* Create a new MD instance and add it to the existing instance
+ of DF. */
+
+void
+df_md_add_problem (void)
+{
+ df_add_problem (&problem_MD);
+}
+
+
+
#define DF_CHAIN 4 /* Def-Use and/or Use-Def Chains. */
#define DF_BYTE_LR 5 /* Subreg tracking lr. */
#define DF_NOTE 6 /* REG_DEF and REG_UNUSED notes. */
+#define DF_MD 7 /* Multiple Definitions. */
-#define DF_LAST_PROBLEM_PLUS1 (DF_NOTE + 1)
+#define DF_LAST_PROBLEM_PLUS1 (DF_MD + 1)
/* Dataflow direction. */
enum df_flow_dir
#define DF_LR_BB_INFO(BB) (df_lr_get_bb_info((BB)->index))
#define DF_LIVE_BB_INFO(BB) (df_live_get_bb_info((BB)->index))
#define DF_BYTE_LR_BB_INFO(BB) (df_byte_lr_get_bb_info((BB)->index))
+#define DF_MD_BB_INFO(BB) (df_md_get_bb_info((BB)->index))
/* Most transformations that wish to use live register analysis will
use these macros. This info is the and of the lr and live sets. */
};
+/* Multiple reaching definitions. All bitmaps are referenced by the
+ register number. */
+
+struct df_md_bb_info
+{
+ /* Local sets to describe the basic blocks. */
+ bitmap gen; /* Partial/conditional definitions live at BB out. */
+ bitmap kill; /* Other definitions that are live at BB out. */
+ bitmap init; /* Definitions coming from dominance frontier edges. */
+
+ /* The results of the dataflow problem. */
+ bitmap in; /* Just before the block itself. */
+ bitmap out; /* At the bottom of the block. */
+};
+
+
/* Live registers, a backwards dataflow problem. All bitmaps are
referenced by the register number. */
#define df_chain (df->problems_by_index[DF_CHAIN])
#define df_byte_lr (df->problems_by_index[DF_BYTE_LR])
#define df_note (df->problems_by_index[DF_NOTE])
+#define df_md (df->problems_by_index[DF_MD])
/* This symbol turns on checking that each modification of the cfg has
been identified to the appropriate df routines. It is not part of
extern void df_byte_lr_simulate_artificial_refs_at_top (basic_block, bitmap);
extern void df_byte_lr_simulate_artificial_refs_at_end (basic_block, bitmap);
extern void df_note_add_problem (void);
+extern void df_md_add_problem (void);
+extern void df_md_simulate_artificial_defs_at_top (basic_block, bitmap);
+extern void df_md_simulate_one_insn (basic_block, rtx, bitmap);
extern void df_simulate_find_defs (rtx, bitmap);
extern void df_simulate_defs (rtx, bitmap);
extern void df_simulate_uses (rtx, bitmap);
return NULL;
}
+static inline struct df_md_bb_info *
+df_md_get_bb_info (unsigned int index)
+{
+ if (index < df_md->block_info_size)
+ return (struct df_md_bb_info *) df_md->block_info[index];
+ else
+ return NULL;
+}
+
static inline struct df_live_bb_info *
df_live_get_bb_info (unsigned int index)
{
#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
}
-/* Return the only bit between FIRST and LAST that is set in B,
- or -1 if there are zero or more than one such bits. */
+/* 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 inline int
-bitmap_only_bit_between (const_bitmap b, unsigned first, unsigned last)
+static void
+process_defs (bitmap local_md, df_ref *def_rec, int top_flag)
{
- bitmap_iterator bi;
- unsigned bit, bit2;
+ 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 (last < first)
- return -1;
+ if ((DF_REF_FLAGS (def) & DF_REF_AT_TOP) != top_flag)
+ continue;
- bmp_iter_set_init (&bi, b, first, &bit);
- if (bmp_iter_set (&bi, &bit) && bit <= last)
- {
- bit2 = bit;
- bmp_iter_next (&bi, &bit2);
- if (!bmp_iter_set (&bi, &bit2) || bit2 > last)
- return bit;
+ 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);
+ }
}
- return -1;
}
/* Fill the use_def_ref vector with values for the uses in USE_REC,
- taking reaching definitions info from LOCAL_RD. TOP_FLAG says
- which artificials uses should be used, when USE_REC is an
- artificial use vector. */
+ 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_rd, df_ref *use_rec, int top_flag)
+process_uses (bitmap local_md, df_ref *use_rec, int top_flag)
{
df_ref use;
while ((use = *use_rec++) != NULL)
- if (top_flag == (DF_REF_FLAGS (use) & DF_REF_AT_TOP))
+ if ((DF_REF_FLAGS (use) & DF_REF_AT_TOP) == top_flag)
{
- unsigned int uregno = DF_REF_REGNO (use);
- unsigned int first = DF_DEFS_BEGIN (uregno);
- unsigned int last = first + DF_DEFS_COUNT (uregno) - 1;
- int defno = bitmap_only_bit_between (local_rd, first, last);
- df_ref def = (defno == -1) ? NULL : DF_DEFS_GET (defno);
+ 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);
- VEC_replace (df_ref, use_def_ref, DF_REF_ID (use), def);
+ /* 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);
+ }
}
-/* Do dataflow analysis and use reaching definitions to build
- a vector holding the reaching definitions of uses that have a
- single RD. */
+/* Build a vector holding the reaching definitions of uses reached by a
+ single dominating definition. */
static void
build_single_def_use_links (void)
{
- basic_block bb;
- bitmap local_rd = BITMAP_ALLOC (NULL);
+ struct dom_walk_data walk_data;
+ bitmap local_md;
- /* We use reaching definitions to compute our restricted use-def chains. */
+ /* We use the multiple definitions problem to compute our restricted
+ use-def chains. */
df_set_flags (DF_EQ_NOTES);
- df_rd_add_problem ();
+ 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 (df_ref, heap, use_def_ref, DF_USES_TABLE_SIZE ());
+ VEC_safe_grow_cleared (df_ref, heap, use_def_ref, DF_USES_TABLE_SIZE ());
- FOR_EACH_BB (bb)
- {
- int bb_index = bb->index;
- struct df_rd_bb_info *bb_info = df_rd_get_bb_info (bb_index);
- rtx insn;
-
- bitmap_copy (local_rd, bb_info->in);
- process_uses (local_rd, df_get_artificial_uses (bb_index), DF_REF_AT_TOP);
-
- df_rd_simulate_artificial_defs_at_top (bb, local_rd);
- FOR_BB_INSNS (bb, insn)
- if (INSN_P (insn))
- {
- unsigned int uid = INSN_UID (insn);
- process_uses (local_rd, DF_INSN_UID_USES (uid), 0);
- process_uses (local_rd, DF_INSN_UID_EQ_USES (uid), 0);
- df_rd_simulate_one_insn (bb, insn, local_rd);
- }
+ reg_defs = VEC_alloc (df_ref, heap, max_reg_num ());
+ VEC_safe_grow_cleared (df_ref, heap, reg_defs, max_reg_num ());
- process_uses (local_rd, df_get_artificial_uses (bb_index), 0);
- }
+ 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;
- BITMAP_FREE (local_rd);
+ 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
int regno;
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. */
+ /* 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))
/* Time spent in dataflow problems. */
DEFTIMEVAR (TV_DF_SCAN , "df scan insns")
-DEFTIMEVAR (TV_DF_RU , "df reaching uses")
+DEFTIMEVAR (TV_DF_MD , "df multiple defs")
DEFTIMEVAR (TV_DF_RD , "df reaching defs")
DEFTIMEVAR (TV_DF_LR , "df live regs")
DEFTIMEVAR (TV_DF_LIVE , "df live&initialized regs")
projects / platform / upstream / linaro-gcc.git / commitdiff