global.c (global_alloc): Call make_accurate_live_analysis.
2004-05-25 Vladimir Makarov <vmakarov@redhat.com> * global.c (global_alloc): Call make_accurate_live_analysis. (record_one_conflict): Remove dead code. (mark_reg_clobber): Remove ATTRIBUTE_UNUSED for parameter data. (bb_info): New structure. (BB_INFO, BB_INFO_BY_INDEX): New macros. (allocate_bb_info, free_bb_info, mark_reg_change, calculate_local_reg_bb_info, set_up_bb_rts_numbers, rpost_cmp, modify_bb_reg_pav, calculate_reg_pav, make_accurate_live_analysis): New functions. From-SVN: r82254
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Vladimir Makarov
Vladimir Makarov
parent
435317e25c
commit
9abe5d07d9
2 changed files with 288 additions and 13 deletions
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@ -1,3 +1,15 @@
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2004-05-25 Vladimir Makarov <vmakarov@redhat.com>
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* global.c (global_alloc): Call make_accurate_live_analysis.
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(record_one_conflict): Remove dead code.
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(mark_reg_clobber): Remove ATTRIBUTE_UNUSED for parameter data.
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(bb_info): New structure.
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(BB_INFO, BB_INFO_BY_INDEX): New macros.
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(allocate_bb_info, free_bb_info, mark_reg_change,
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calculate_local_reg_bb_info, set_up_bb_rts_numbers, rpost_cmp,
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modify_bb_reg_pav, calculate_reg_pav,
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make_accurate_live_analysis): New functions.
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2004-05-25 Devang Patel <dpatel@apple.com>
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* alias.c (init_alias_analysis): Use ggc_calloc instead of
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289
gcc/global.c
289
gcc/global.c
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@ -306,7 +306,18 @@ static void set_preference (rtx, rtx);
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static void dump_conflicts (FILE *);
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static void reg_becomes_live (rtx, rtx, void *);
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static void reg_dies (int, enum machine_mode, struct insn_chain *);
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static void allocate_bb_info (void);
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static void free_bb_info (void);
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static void calculate_local_reg_bb_info (void);
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static void set_up_bb_rts_numbers (void);
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static int rpost_cmp (const void *, const void *);
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static bool modify_bb_reg_pav (basic_block, basic_block, bool);
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static void calculate_reg_pav (void);
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static void make_accurate_live_analysis (void);
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/* Perform allocation of pseudo-registers not allocated by local_alloc.
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FILE is a file to output debugging information on,
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or zero if such output is not desired.
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@ -329,6 +340,8 @@ global_alloc (FILE *file)
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size_t i;
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rtx x;
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make_accurate_live_analysis ();
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max_allocno = 0;
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/* A machine may have certain hard registers that
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@ -1377,18 +1390,7 @@ record_one_conflict (int regno)
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IOR_HARD_REG_SET (allocno[ialloc].hard_reg_conflicts, hard_regs_live);
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for (j = allocno_row_words - 1; j >= 0; j--)
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{
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#if 0
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int k;
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for (k = 0; k < n_no_conflict_pairs; k++)
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if (! ((j == no_conflict_pairs[k].allocno1
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&& ialloc == no_conflict_pairs[k].allocno2)
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(j == no_conflict_pairs[k].allocno2
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&& ialloc == no_conflict_pairs[k].allocno1)))
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#endif /* 0 */
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conflicts[ialloc_prod + j] |= allocnos_live[j];
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}
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conflicts[ialloc_prod + j] |= allocnos_live[j];
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}
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}
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@ -1503,7 +1505,7 @@ mark_reg_store (rtx reg, rtx setter, void *data ATTRIBUTE_UNUSED)
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/* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */
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static void
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mark_reg_clobber (rtx reg, rtx setter, void *data ATTRIBUTE_UNUSED)
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mark_reg_clobber (rtx reg, rtx setter, void *data)
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{
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if (GET_CODE (setter) == CLOBBER)
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mark_reg_store (reg, setter, data);
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@ -1973,3 +1975,264 @@ dump_global_regs (FILE *file)
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fprintf (file, " %d", i);
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fprintf (file, "\n\n");
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}
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/* This page contains code to make live information more accurate.
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The accurate register liveness at program point P means:
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o there is a path from P to usage of the register and the
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register is not redefined or killed on the path.
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o register at P is partially available, i.e. there is a path from
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a register definition to the point P and the register is not
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killed (clobbered) on the path
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The standard GCC live information means only the first condition.
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Without the partial availability, there will be more register
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conflicts and as a consequence worse register allocation. The
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typical example where the information can be different is a
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register initialized in the loop at the basic block preceding the
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loop in CFG. */
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/* The following structure contains basic block data flow information
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used to calculate partial availability of registers. */
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struct bb_info
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{
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/* The basic block reverse post-order number. */
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int rts_number;
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/* Registers correspondingly killed (clobbered) and defined but not
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killed afterward in the basic block. */
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bitmap killed, avloc;
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/* Registers partially available correspondingly at the start and
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end of the basic block. */
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bitmap pavin, pavout;
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};
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/* Macros for accessing data flow information of basic blocks. */
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#define BB_INFO(BB) ((struct bb_info *) (BB)->aux)
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#define BB_INFO_BY_INDEX(N) BB_INFO (BASIC_BLOCK(N))
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/* The function allocates the info structures of each basic block. It
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also initialized PAVIN and PAVOUT as if all hard registers were
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partially available. */
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static void
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allocate_bb_info (void)
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{
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int i;
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basic_block bb;
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struct bb_info *bb_info;
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bitmap init;
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alloc_aux_for_blocks (sizeof (struct bb_info));
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init = BITMAP_XMALLOC ();
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for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
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bitmap_set_bit (init, i);
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FOR_EACH_BB (bb)
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{
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bb_info = bb->aux;
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bb_info->avloc = BITMAP_XMALLOC ();
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bb_info->killed = BITMAP_XMALLOC ();
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bb_info->pavin = BITMAP_XMALLOC ();
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bb_info->pavout = BITMAP_XMALLOC ();
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bitmap_copy (bb_info->pavin, init);
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bitmap_copy (bb_info->pavout, init);
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}
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BITMAP_XFREE (init);
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}
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/* The function frees the allocated info of all basic blocks. */
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static void
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free_bb_info (void)
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{
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basic_block bb;
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struct bb_info *bb_info;
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FOR_EACH_BB (bb)
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{
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bb_info = BB_INFO (bb);
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BITMAP_XFREE (bb_info->pavout);
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BITMAP_XFREE (bb_info->pavin);
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BITMAP_XFREE (bb_info->killed);
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BITMAP_XFREE (bb_info->avloc);
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}
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free_aux_for_blocks ();
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}
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/* The function modifies local info for register REG being changed in
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SETTER. DATA is used to pass the current basic block info. */
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static void
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mark_reg_change (rtx reg, rtx setter, void *data)
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{
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int regno;
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basic_block bb = data;
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struct bb_info *bb_info = BB_INFO (bb);
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if (GET_CODE (reg) == SUBREG)
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reg = SUBREG_REG (reg);
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if (GET_CODE (reg) != REG)
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return;
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regno = REGNO (reg);
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bitmap_set_bit (bb_info->killed, regno);
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if (GET_CODE (setter) != CLOBBER)
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bitmap_set_bit (bb_info->avloc, regno);
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else
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bitmap_clear_bit (bb_info->avloc, regno);
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}
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/* The function calculates local info for each basic block. */
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static void
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calculate_local_reg_bb_info (void)
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{
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basic_block bb;
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rtx insn, bound;
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FOR_EACH_BB (bb)
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{
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bound = NEXT_INSN (BB_END (bb));
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for (insn = BB_HEAD (bb); insn != bound; insn = NEXT_INSN (insn))
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if (INSN_P (insn))
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note_stores (PATTERN (insn), mark_reg_change, bb);
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}
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}
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/* The function sets up reverse post-order number of each basic
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block. */
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static void
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set_up_bb_rts_numbers (void)
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{
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int i;
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int *rts_order;
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rts_order = xmalloc (sizeof (int) * n_basic_blocks);
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flow_reverse_top_sort_order_compute (rts_order);
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for (i = 0; i < n_basic_blocks; i++)
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BB_INFO_BY_INDEX (rts_order [i])->rts_number = i;
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free (rts_order);
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}
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/* Compare function for sorting blocks in reverse postorder. */
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static int
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rpost_cmp (const void *bb1, const void *bb2)
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{
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basic_block b1 = *(basic_block *) bb1, b2 = *(basic_block *) bb2;
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return BB_INFO (b2)->rts_number - BB_INFO (b1)->rts_number;
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}
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/* The function calculates partial availability of registers. The
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function calculates partial availability at the end of basic block
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BB by propagating partial availability at end of predecessor basic
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block PRED. The function returns true if the partial availability
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at the end of BB has been changed or if CHANGED_P. We have the
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following equations:
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bb.pavin = empty for entry block | union (pavout of predecessors)
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bb.pavout = union (bb.pavin - b.killed, bb.avloc) */
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static bool
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modify_bb_reg_pav (basic_block bb, basic_block pred, bool changed_p)
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{
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struct bb_info *bb_info;
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bitmap bb_pavin, bb_pavout;
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bb_info = BB_INFO (bb);
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bb_pavin = bb_info->pavin;
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bb_pavout = bb_info->pavout;
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if (pred->index != ENTRY_BLOCK)
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bitmap_a_or_b (bb_pavin, bb_pavin, BB_INFO (pred)->pavout);
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changed_p |= bitmap_union_of_diff (bb_pavout, bb_info->avloc,
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bb_pavin, bb_info->killed);
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return changed_p;
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}
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/* The function calculates partial register availability. */
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static void
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calculate_reg_pav (void)
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{
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basic_block bb, succ;
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edge e;
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bool changed_p;
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int i, nel;
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varray_type bbs, new_bbs, temp;
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basic_block *bb_array;
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sbitmap wset;
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VARRAY_BB_INIT (bbs, n_basic_blocks, "basic blocks");
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VARRAY_BB_INIT (new_bbs, n_basic_blocks, "basic blocks for the next iter.");
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FOR_EACH_BB (bb)
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{
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VARRAY_PUSH_BB (bbs, bb);
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}
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wset = sbitmap_alloc (n_basic_blocks + 1);
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while (VARRAY_ACTIVE_SIZE (bbs))
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{
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bb_array = &VARRAY_BB (bbs, 0);
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nel = VARRAY_ACTIVE_SIZE (bbs);
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qsort (bb_array, nel, sizeof (basic_block), rpost_cmp);
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sbitmap_zero (wset);
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for (i = 0; i < nel; i++)
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{
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bb = bb_array [i];
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changed_p = 0;
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for (e = bb->pred; e; e = e->pred_next)
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changed_p = modify_bb_reg_pav (bb, e->src, changed_p);
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if (changed_p)
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for (e = bb->succ; e; e = e->succ_next)
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{
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succ = e->dest;
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if (succ->index != EXIT_BLOCK && !TEST_BIT (wset, succ->index))
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{
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SET_BIT (wset, succ->index);
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VARRAY_PUSH_BB (new_bbs, succ);
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}
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}
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}
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temp = bbs;
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bbs = new_bbs;
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new_bbs = temp;
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VARRAY_POP_ALL (new_bbs);
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}
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sbitmap_free (wset);
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}
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/* The following function makes live information more accurate by
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modifying global_live_at_start and global_live_at_end of basic
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blocks. After the function call a register lives at a program
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point only if it is initialized on a path from CFG entry to the
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program point. The standard GCC life analysis permits registers to
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live uninitialized. */
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static void
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make_accurate_live_analysis (void)
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{
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basic_block bb;
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struct bb_info *bb_info;
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max_regno = max_reg_num ();
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compact_blocks ();
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allocate_bb_info ();
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calculate_local_reg_bb_info ();
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set_up_bb_rts_numbers ();
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calculate_reg_pav ();
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FOR_EACH_BB (bb)
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{
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bb_info = BB_INFO (bb);
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bitmap_a_and_b (bb->global_live_at_start, bb->global_live_at_start,
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bb_info->pavin);
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bitmap_a_and_b (bb->global_live_at_end, bb->global_live_at_end,
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bb_info->pavout);
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}
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free_bb_info ();
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}
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