X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fcfgcleanup.c;h=b59cf7bc9f0ebbaec00482b7282412b0a363d398;hb=aecc03acf6cf9a415e9d66c5dba822a3914620b4;hp=75f56519a26ca79ef847ea11b7d861c6e61f99ea;hpb=dcb172b4aee2541920b5793aa338e40824f521b4;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c index 75f56519a26..b59cf7bc9f0 100644 --- a/gcc/cfgcleanup.c +++ b/gcc/cfgcleanup.c @@ -1,6 +1,6 @@ /* Control flow optimization code for GNU compiler. Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010 + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2010, 2011 Free Software Foundation, Inc. This file is part of GCC. @@ -43,7 +43,7 @@ along with GCC; see the file COPYING3. If not see #include "insn-config.h" #include "flags.h" #include "recog.h" -#include "toplev.h" +#include "diagnostic-core.h" #include "cselib.h" #include "params.h" #include "tm_p.h" @@ -65,10 +65,14 @@ static bool first_pass; /* Set to true if crossjumps occured in the latest run of try_optimize_cfg. */ static bool crossjumps_occured; -static bool try_crossjump_to_edge (int, edge, edge); +/* Set to true if we couldn't run an optimization due to stale liveness + information; we should run df_analyze to enable more opportunities. */ +static bool block_was_dirty; + +static bool try_crossjump_to_edge (int, edge, edge, enum replace_direction); static bool try_crossjump_bb (int, basic_block); static bool outgoing_edges_match (int, basic_block, basic_block); -static bool old_insns_match_p (int, rtx, rtx); +static enum replace_direction old_insns_match_p (int, rtx, rtx); static void merge_blocks_move_predecessor_nojumps (basic_block, basic_block); static void merge_blocks_move_successor_nojumps (basic_block, basic_block); @@ -204,13 +208,11 @@ mark_effect (rtx exp, regset nonequal) { dest = XEXP (exp, 0); regno = REGNO (dest); - CLEAR_REGNO_REG_SET (nonequal, regno); - if (regno < FIRST_PSEUDO_REGISTER) - { - int n = hard_regno_nregs[regno][GET_MODE (dest)]; - while (--n > 0) - CLEAR_REGNO_REG_SET (nonequal, regno + n); - } + if (HARD_REGISTER_NUM_P (regno)) + bitmap_clear_range (nonequal, regno, + hard_regno_nregs[regno][GET_MODE (dest)]); + else + bitmap_clear_bit (nonequal, regno); } return false; @@ -223,13 +225,11 @@ mark_effect (rtx exp, regset nonequal) if (!REG_P (dest)) return true; regno = REGNO (dest); - SET_REGNO_REG_SET (nonequal, regno); - if (regno < FIRST_PSEUDO_REGISTER) - { - int n = hard_regno_nregs[regno][GET_MODE (dest)]; - while (--n > 0) - SET_REGNO_REG_SET (nonequal, regno + n); - } + if (HARD_REGISTER_NUM_P (regno)) + bitmap_set_range (nonequal, regno, + hard_regno_nregs[regno][GET_MODE (dest)]); + else + bitmap_set_bit (nonequal, regno); return false; default: @@ -431,7 +431,7 @@ try_forward_edges (int mode, basic_block b) int counter, goto_locus; bool threaded = false; int nthreaded_edges = 0; - bool may_thread = first_pass | df_get_bb_dirty (b); + bool may_thread = first_pass || (b->flags & BB_MODIFIED) != 0; /* Skip complex edges because we don't know how to update them. @@ -466,7 +466,7 @@ try_forward_edges (int mode, basic_block b) { basic_block new_target = NULL; bool new_target_threaded = false; - may_thread |= df_get_bb_dirty (target); + may_thread |= (target->flags & BB_MODIFIED) != 0; if (FORWARDER_BLOCK_P (target) && !(single_succ_edge (target)->flags & EDGE_CROSSING) @@ -480,22 +480,34 @@ try_forward_edges (int mode, basic_block b) { /* When not optimizing, ensure that edges or forwarder blocks with different locus are not optimized out. */ - int locus = single_succ_edge (target)->goto_locus; - - if (locus && goto_locus && !locator_eq (locus, goto_locus)) - counter = n_basic_blocks; - else if (locus) - goto_locus = locus; + int new_locus = single_succ_edge (target)->goto_locus; + int locus = goto_locus; - if (INSN_P (BB_END (target))) + if (new_locus && locus && !locator_eq (new_locus, locus)) + new_target = NULL; + else { - locus = INSN_LOCATOR (BB_END (target)); + rtx last; + + if (new_locus) + locus = new_locus; + + last = BB_END (target); + if (DEBUG_INSN_P (last)) + last = prev_nondebug_insn (last); + + new_locus = last && INSN_P (last) + ? INSN_LOCATOR (last) : 0; + + if (new_locus && locus && !locator_eq (new_locus, locus)) + new_target = NULL; + else + { + if (new_locus) + locus = new_locus; - if (locus && goto_locus - && !locator_eq (locus, goto_locus)) - counter = n_basic_blocks; - else if (locus) - goto_locus = locus; + goto_locus = locus; + } } } } @@ -587,9 +599,6 @@ try_forward_edges (int mode, basic_block b) + REG_BR_PROB_BASE / 2) / REG_BR_PROB_BASE); - if (!FORWARDER_BLOCK_P (b) && forwarder_block_p (b)) - b->flags |= BB_FORWARDER_BLOCK; - do { edge t; @@ -634,8 +643,7 @@ try_forward_edges (int mode, basic_block b) ei_next (&ei); } - if (threaded_edges) - free (threaded_edges); + free (threaded_edges); return changed; } @@ -788,7 +796,6 @@ merge_blocks_move (edge e, basic_block b, basic_block c, int mode) edge tmp_edge, b_fallthru_edge; bool c_has_outgoing_fallthru; bool b_has_incoming_fallthru; - edge_iterator ei; /* Avoid overactive code motion, as the forwarder blocks should be eliminated by edge redirection instead. One exception might have @@ -801,16 +808,10 @@ merge_blocks_move (edge e, basic_block b, basic_block c, int mode) and loop notes. This is done by squeezing out all the notes and leaving them there to lie. Not ideal, but functional. */ - FOR_EACH_EDGE (tmp_edge, ei, c->succs) - if (tmp_edge->flags & EDGE_FALLTHRU) - break; - + tmp_edge = find_fallthru_edge (c->succs); c_has_outgoing_fallthru = (tmp_edge != NULL); - FOR_EACH_EDGE (tmp_edge, ei, b->preds) - if (tmp_edge->flags & EDGE_FALLTHRU) - break; - + tmp_edge = find_fallthru_edge (b->preds); b_has_incoming_fallthru = (tmp_edge != NULL); b_fallthru_edge = tmp_edge; next = b->prev_bb; @@ -882,7 +883,7 @@ merge_memattrs (rtx x, rtx y) MEM_ATTRS (x) = 0; else { - rtx mem_size; + HOST_WIDE_INT mem_size; if (MEM_ALIAS_SET (x) != MEM_ALIAS_SET (y)) { @@ -894,24 +895,28 @@ merge_memattrs (rtx x, rtx y) { set_mem_expr (x, 0); set_mem_expr (y, 0); - set_mem_offset (x, 0); - set_mem_offset (y, 0); + clear_mem_offset (x); + clear_mem_offset (y); } - else if (MEM_OFFSET (x) != MEM_OFFSET (y)) + else if (MEM_OFFSET_KNOWN_P (x) != MEM_OFFSET_KNOWN_P (y) + || (MEM_OFFSET_KNOWN_P (x) + && MEM_OFFSET (x) != MEM_OFFSET (y))) { - set_mem_offset (x, 0); - set_mem_offset (y, 0); + clear_mem_offset (x); + clear_mem_offset (y); } - if (!MEM_SIZE (x)) - mem_size = NULL_RTX; - else if (!MEM_SIZE (y)) - mem_size = NULL_RTX; + if (MEM_SIZE_KNOWN_P (x) && MEM_SIZE_KNOWN_P (y)) + { + mem_size = MAX (MEM_SIZE (x), MEM_SIZE (y)); + set_mem_size (x, mem_size); + set_mem_size (y, mem_size); + } else - mem_size = GEN_INT (MAX (INTVAL (MEM_SIZE (x)), - INTVAL (MEM_SIZE (y)))); - set_mem_size (x, mem_size); - set_mem_size (y, mem_size); + { + clear_mem_size (x); + clear_mem_size (y); + } set_mem_align (x, MIN (MEM_ALIGN (x), MEM_ALIGN (y))); set_mem_align (y, MEM_ALIGN (x)); @@ -941,27 +946,162 @@ merge_memattrs (rtx x, rtx y) } -/* Return true if I1 and I2 are equivalent and thus can be crossjumped. */ + /* Checks if patterns P1 and P2 are equivalent, apart from the possibly + different single sets S1 and S2. */ static bool +equal_different_set_p (rtx p1, rtx s1, rtx p2, rtx s2) +{ + int i; + rtx e1, e2; + + if (p1 == s1 && p2 == s2) + return true; + + if (GET_CODE (p1) != PARALLEL || GET_CODE (p2) != PARALLEL) + return false; + + if (XVECLEN (p1, 0) != XVECLEN (p2, 0)) + return false; + + for (i = 0; i < XVECLEN (p1, 0); i++) + { + e1 = XVECEXP (p1, 0, i); + e2 = XVECEXP (p2, 0, i); + if (e1 == s1 && e2 == s2) + continue; + if (reload_completed + ? rtx_renumbered_equal_p (e1, e2) : rtx_equal_p (e1, e2)) + continue; + + return false; + } + + return true; +} + +/* Examine register notes on I1 and I2 and return: + - dir_forward if I1 can be replaced by I2, or + - dir_backward if I2 can be replaced by I1, or + - dir_both if both are the case. */ + +static enum replace_direction +can_replace_by (rtx i1, rtx i2) +{ + rtx s1, s2, d1, d2, src1, src2, note1, note2; + bool c1, c2; + + /* Check for 2 sets. */ + s1 = single_set (i1); + s2 = single_set (i2); + if (s1 == NULL_RTX || s2 == NULL_RTX) + return dir_none; + + /* Check that the 2 sets set the same dest. */ + d1 = SET_DEST (s1); + d2 = SET_DEST (s2); + if (!(reload_completed + ? rtx_renumbered_equal_p (d1, d2) : rtx_equal_p (d1, d2))) + return dir_none; + + /* Find identical req_equiv or reg_equal note, which implies that the 2 sets + set dest to the same value. */ + note1 = find_reg_equal_equiv_note (i1); + note2 = find_reg_equal_equiv_note (i2); + if (!note1 || !note2 || !rtx_equal_p (XEXP (note1, 0), XEXP (note2, 0)) + || !CONST_INT_P (XEXP (note1, 0))) + return dir_none; + + if (!equal_different_set_p (PATTERN (i1), s1, PATTERN (i2), s2)) + return dir_none; + + /* Although the 2 sets set dest to the same value, we cannot replace + (set (dest) (const_int)) + by + (set (dest) (reg)) + because we don't know if the reg is live and has the same value at the + location of replacement. */ + src1 = SET_SRC (s1); + src2 = SET_SRC (s2); + c1 = CONST_INT_P (src1); + c2 = CONST_INT_P (src2); + if (c1 && c2) + return dir_both; + else if (c2) + return dir_forward; + else if (c1) + return dir_backward; + + return dir_none; +} + +/* Merges directions A and B. */ + +static enum replace_direction +merge_dir (enum replace_direction a, enum replace_direction b) +{ + /* Implements the following table: + |bo fw bw no + ---+----------- + bo |bo fw bw no + fw |-- fw no no + bw |-- -- bw no + no |-- -- -- no. */ + + if (a == b) + return a; + + if (a == dir_both) + return b; + if (b == dir_both) + return a; + + return dir_none; +} + +/* Examine I1 and I2 and return: + - dir_forward if I1 can be replaced by I2, or + - dir_backward if I2 can be replaced by I1, or + - dir_both if both are the case. */ + +static enum replace_direction old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2) { rtx p1, p2; /* Verify that I1 and I2 are equivalent. */ if (GET_CODE (i1) != GET_CODE (i2)) - return false; + return dir_none; /* __builtin_unreachable() may lead to empty blocks (ending with NOTE_INSN_BASIC_BLOCK). They may be crossjumped. */ if (NOTE_INSN_BASIC_BLOCK_P (i1) && NOTE_INSN_BASIC_BLOCK_P (i2)) - return true; + return dir_both; + + /* ??? Do not allow cross-jumping between different stack levels. */ + p1 = find_reg_note (i1, REG_ARGS_SIZE, NULL); + p2 = find_reg_note (i2, REG_ARGS_SIZE, NULL); + if (p1 && p2) + { + p1 = XEXP (p1, 0); + p2 = XEXP (p2, 0); + if (!rtx_equal_p (p1, p2)) + return dir_none; + + /* ??? Worse, this adjustment had better be constant lest we + have differing incoming stack levels. */ + if (!frame_pointer_needed + && find_args_size_adjust (i1) == HOST_WIDE_INT_MIN) + return dir_none; + } + else if (p1 || p2) + return dir_none; p1 = PATTERN (i1); p2 = PATTERN (i2); if (GET_CODE (p1) != GET_CODE (p2)) - return false; + return dir_none; /* If this is a CALL_INSN, compare register usage information. If we don't check this on stack register machines, the two @@ -982,15 +1122,15 @@ old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2) rtx n2 = find_reg_note (i2, REG_EH_REGION, 0); if (!n1 && n2) - return false; + return dir_none; if (n1 && (!n2 || XEXP (n1, 0) != XEXP (n2, 0))) - return false; + return dir_none; if (!rtx_equal_p (CALL_INSN_FUNCTION_USAGE (i1), CALL_INSN_FUNCTION_USAGE (i2)) || SIBLING_CALL_P (i1) != SIBLING_CALL_P (i2)) - return false; + return dir_none; } #ifdef STACK_REGS @@ -1019,15 +1159,15 @@ old_insns_match_p (int mode ATTRIBUTE_UNUSED, rtx i1, rtx i2) SET_HARD_REG_BIT (i2_regset, REGNO (XEXP (note, 0))); if (!hard_reg_set_equal_p (i1_regset, i2_regset)) - return false; + return dir_none; } #endif if (reload_completed ? rtx_renumbered_equal_p (p1, p2) : rtx_equal_p (p1, p2)) - return true; + return dir_both; - return false; + return can_replace_by (i1, i2); } /* When comparing insns I1 and I2 in flow_find_cross_jump or @@ -1053,18 +1193,71 @@ merge_notes (rtx i1, rtx i2) } } + /* Walks from I1 in BB1 backward till the next non-debug insn, and returns the + resulting insn in I1, and the corresponding bb in BB1. At the head of a + bb, if there is a predecessor bb that reaches this bb via fallthru, and + FOLLOW_FALLTHRU, walks further in the predecessor bb and registers this in + DID_FALLTHRU. Otherwise, stops at the head of the bb. */ + +static void +walk_to_nondebug_insn (rtx *i1, basic_block *bb1, bool follow_fallthru, + bool *did_fallthru) +{ + edge fallthru; + + *did_fallthru = false; + + /* Ignore notes. */ + while (!NONDEBUG_INSN_P (*i1)) + { + if (*i1 != BB_HEAD (*bb1)) + { + *i1 = PREV_INSN (*i1); + continue; + } + + if (!follow_fallthru) + return; + + fallthru = find_fallthru_edge ((*bb1)->preds); + if (!fallthru || fallthru->src == ENTRY_BLOCK_PTR_FOR_FUNCTION (cfun) + || !single_succ_p (fallthru->src)) + return; + + *bb1 = fallthru->src; + *i1 = BB_END (*bb1); + *did_fallthru = true; + } +} + /* Look through the insns at the end of BB1 and BB2 and find the longest - sequence that are equivalent. Store the first insns for that sequence - in *F1 and *F2 and return the sequence length. + sequence that are either equivalent, or allow forward or backward + replacement. Store the first insns for that sequence in *F1 and *F2 and + return the sequence length. + + DIR_P indicates the allowed replacement direction on function entry, and + the actual replacement direction on function exit. If NULL, only equivalent + sequences are allowed. To simplify callers of this function, if the blocks match exactly, store the head of the blocks in *F1 and *F2. */ int -flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) +flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2, + enum replace_direction *dir_p) { rtx i1, i2, last1, last2, afterlast1, afterlast2; int ninsns = 0; + rtx p1; + enum replace_direction dir, last_dir, afterlast_dir; + bool follow_fallthru, did_fallthru; + + if (dir_p) + dir = *dir_p; + else + dir = dir_both; + afterlast_dir = dir; + last_dir = afterlast_dir; /* Skip simple jumps at the end of the blocks. Complex jumps still need to be compared for equivalence, which we'll do below. */ @@ -1091,17 +1284,37 @@ flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) while (true) { - /* Ignore notes. */ - while (!NONDEBUG_INSN_P (i1) && i1 != BB_HEAD (bb1)) - i1 = PREV_INSN (i1); - - while (!NONDEBUG_INSN_P (i2) && i2 != BB_HEAD (bb2)) - i2 = PREV_INSN (i2); + /* In the following example, we can replace all jumps to C by jumps to A. + + This removes 4 duplicate insns. + [bb A] insn1 [bb C] insn1 + insn2 insn2 + [bb B] insn3 insn3 + insn4 insn4 + jump_insn jump_insn + + We could also replace all jumps to A by jumps to C, but that leaves B + alive, and removes only 2 duplicate insns. In a subsequent crossjump + step, all jumps to B would be replaced with jumps to the middle of C, + achieving the same result with more effort. + So we allow only the first possibility, which means that we don't allow + fallthru in the block that's being replaced. */ + + follow_fallthru = dir_p && dir != dir_forward; + walk_to_nondebug_insn (&i1, &bb1, follow_fallthru, &did_fallthru); + if (did_fallthru) + dir = dir_backward; + + follow_fallthru = dir_p && dir != dir_backward; + walk_to_nondebug_insn (&i2, &bb2, follow_fallthru, &did_fallthru); + if (did_fallthru) + dir = dir_forward; if (i1 == BB_HEAD (bb1) || i2 == BB_HEAD (bb2)) break; - if (!old_insns_match_p (0, i1, i2)) + dir = merge_dir (dir, old_insns_match_p (0, i1, i2)); + if (dir == dir_none || (!dir_p && dir != dir_both)) break; merge_memattrs (i1, i2); @@ -1113,7 +1326,11 @@ flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) afterlast1 = last1, afterlast2 = last2; last1 = i1, last2 = i2; - ninsns++; + afterlast_dir = last_dir; + last_dir = dir; + p1 = PATTERN (i1); + if (!(GET_CODE (p1) == USE || GET_CODE (p1) == CLOBBER)) + ninsns++; } i1 = PREV_INSN (i1); @@ -1124,7 +1341,7 @@ flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) /* Don't allow the insn after a compare to be shared by cross-jumping unless the compare is also shared. */ if (ninsns && reg_mentioned_p (cc0_rtx, last1) && ! sets_cc0_p (last1)) - last1 = afterlast1, last2 = afterlast2, ninsns--; + last1 = afterlast1, last2 = afterlast2, last_dir = afterlast_dir, ninsns--; #endif /* Include preceding notes and labels in the cross-jump. One, @@ -1132,12 +1349,14 @@ flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) Two, it keeps line number notes as matched as may be. */ if (ninsns) { + bb1 = BLOCK_FOR_INSN (last1); while (last1 != BB_HEAD (bb1) && !NONDEBUG_INSN_P (PREV_INSN (last1))) last1 = PREV_INSN (last1); if (last1 != BB_HEAD (bb1) && LABEL_P (PREV_INSN (last1))) last1 = PREV_INSN (last1); + bb2 = BLOCK_FOR_INSN (last2); while (last2 != BB_HEAD (bb2) && !NONDEBUG_INSN_P (PREV_INSN (last2))) last2 = PREV_INSN (last2); @@ -1148,6 +1367,8 @@ flow_find_cross_jump (basic_block bb1, basic_block bb2, rtx *f1, rtx *f2) *f2 = last2; } + if (dir_p) + *dir_p = last_dir; return ninsns; } @@ -1179,13 +1400,24 @@ flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx *f1, while (true) { - - /* Ignore notes. */ + /* Ignore notes, except NOTE_INSN_EPILOGUE_BEG. */ while (!NONDEBUG_INSN_P (i1) && i1 != BB_END (bb1)) - i1 = NEXT_INSN (i1); + { + if (NOTE_P (i1) && NOTE_KIND (i1) == NOTE_INSN_EPILOGUE_BEG) + break; + i1 = NEXT_INSN (i1); + } while (!NONDEBUG_INSN_P (i2) && i2 != BB_END (bb2)) - i2 = NEXT_INSN (i2); + { + if (NOTE_P (i2) && NOTE_KIND (i2) == NOTE_INSN_EPILOGUE_BEG) + break; + i2 = NEXT_INSN (i2); + } + + if ((i1 == BB_END (bb1) && !NONDEBUG_INSN_P (i1)) + || (i2 == BB_END (bb2) && !NONDEBUG_INSN_P (i2))) + break; if (NOTE_P (i1) || NOTE_P (i2) || JUMP_P (i1) || JUMP_P (i2)) @@ -1203,7 +1435,7 @@ flow_find_head_matching_sequence (basic_block bb1, basic_block bb2, rtx *f1, && nehedges1 != nehedges2)) break; - if (!old_insns_match_p (0, i1, i2)) + if (old_insns_match_p (0, i1, i2) != dir_both) break; merge_memattrs (i1, i2); @@ -1256,6 +1488,16 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) edge e1, e2; edge_iterator ei; + /* If we performed shrink-wrapping, edges to the EXIT_BLOCK_PTR can + only be distinguished for JUMP_INSNs. The two paths may differ in + whether they went through the prologue. Sibcalls are fine, we know + that we either didn't need or inserted an epilogue before them. */ + if (crtl->shrink_wrapped + && single_succ_p (bb1) && single_succ (bb1) == EXIT_BLOCK_PTR + && !JUMP_P (BB_END (bb1)) + && !(CALL_P (BB_END (bb1)) && SIBLING_CALL_P (BB_END (bb1)))) + return false; + /* If BB1 has only one successor, we may be looking at either an unconditional jump, or a fake edge to exit. */ if (single_succ_p (bb1) @@ -1432,7 +1674,8 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) rr.update_label_nuses = false; for_each_rtx (&BB_END (bb1), replace_label, &rr); - match = old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)); + match = (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) + == dir_both); if (dump_file && match) fprintf (dump_file, "Tablejumps in bb %i and %i match.\n", @@ -1454,7 +1697,7 @@ outgoing_edges_match (int mode, basic_block bb1, basic_block bb2) /* First ensure that the instructions match. There may be many outgoing edges so this test is generally cheaper. */ - if (!old_insns_match_p (mode, BB_END (bb1), BB_END (bb2))) + if (old_insns_match_p (mode, BB_END (bb1), BB_END (bb2)) != dir_both) return false; /* Search the outgoing edges, ensure that the counts do match, find possible @@ -1547,14 +1790,18 @@ block_has_preserve_label (basic_block bb) /* E1 and E2 are edges with the same destination block. Search their predecessors for common code. If found, redirect control flow from - (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC. */ + (maybe the middle of) E1->SRC to (maybe the middle of) E2->SRC (dir_forward), + or the other way around (dir_backward). DIR specifies the allowed + replacement direction. */ static bool -try_crossjump_to_edge (int mode, edge e1, edge e2) +try_crossjump_to_edge (int mode, edge e1, edge e2, + enum replace_direction dir) { int nmatch; basic_block src1 = e1->src, src2 = e2->src; basic_block redirect_to, redirect_from, to_remove; + basic_block osrc1, osrc2, redirect_edges_to, tmp; rtx newpos1, newpos2; edge s; edge_iterator ei; @@ -1610,7 +1857,24 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) return false; /* ... and part the second. */ - nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2); + nmatch = flow_find_cross_jump (src1, src2, &newpos1, &newpos2, &dir); + + osrc1 = src1; + osrc2 = src2; + if (newpos1 != NULL_RTX) + src1 = BLOCK_FOR_INSN (newpos1); + if (newpos2 != NULL_RTX) + src2 = BLOCK_FOR_INSN (newpos2); + + if (dir == dir_backward) + { +#define SWAP(T, X, Y) do { T tmp = (X); (X) = (Y); (Y) = tmp; } while (0) + SWAP (basic_block, osrc1, osrc2); + SWAP (basic_block, src1, src2); + SWAP (edge, e1, e2); + SWAP (rtx, newpos1, newpos2); +#undef SWAP + } /* Don't proceed with the crossjump unless we found a sufficient number of matching instructions or the 'from' block was totally matched @@ -1634,8 +1898,8 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) rtx label1, label2; rtx table1, table2; - if (tablejump_p (BB_END (src1), &label1, &table1) - && tablejump_p (BB_END (src2), &label2, &table2) + if (tablejump_p (BB_END (osrc1), &label1, &table1) + && tablejump_p (BB_END (osrc2), &label2, &table2) && label1 != label2) { replace_label_data rr; @@ -1650,7 +1914,7 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) /* Do not replace the label in SRC1->END because when deleting a block whose end is a tablejump, the tablejump referenced from the instruction is deleted too. */ - if (insn != BB_END (src1)) + if (insn != BB_END (osrc1)) for_each_rtx (&insn, replace_label, &rr); } } @@ -1691,8 +1955,13 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) /* We may have some registers visible through the block. */ df_set_bb_dirty (redirect_to); + if (osrc2 == src2) + redirect_edges_to = redirect_to; + else + redirect_edges_to = osrc2; + /* Recompute the frequencies and counts of outgoing edges. */ - FOR_EACH_EDGE (s, ei, redirect_to->succs) + FOR_EACH_EDGE (s, ei, redirect_edges_to->succs) { edge s2; edge_iterator ei; @@ -1735,24 +2004,32 @@ try_crossjump_to_edge (int mode, edge e1, edge e2) s2->dest->count = 0; } - if (!redirect_to->frequency && !src1->frequency) + if (!redirect_edges_to->frequency && !src1->frequency) s->probability = (s->probability + s2->probability) / 2; else s->probability - = ((s->probability * redirect_to->frequency + + = ((s->probability * redirect_edges_to->frequency + s2->probability * src1->frequency) - / (redirect_to->frequency + src1->frequency)); + / (redirect_edges_to->frequency + src1->frequency)); } /* Adjust count and frequency for the block. An earlier jump threading pass may have left the profile in an inconsistent state (see update_bb_profile_for_threading) so we must be prepared for overflows. */ - redirect_to->count += src1->count; - redirect_to->frequency += src1->frequency; - if (redirect_to->frequency > BB_FREQ_MAX) - redirect_to->frequency = BB_FREQ_MAX; - update_br_prob_note (redirect_to); + tmp = redirect_to; + do + { + tmp->count += src1->count; + tmp->frequency += src1->frequency; + if (tmp->frequency > BB_FREQ_MAX) + tmp->frequency = BB_FREQ_MAX; + if (tmp == redirect_edges_to) + break; + tmp = find_fallthru_edge (tmp->succs)->dest; + } + while (true); + update_br_prob_note (redirect_edges_to); /* Edit SRC1 to go to REDIRECT_TO at NEWPOS1. */ @@ -1792,8 +2069,6 @@ try_crossjump_bb (int mode, basic_block bb) edge e, e2, fallthru; bool changed; unsigned max, ix, ix2; - basic_block ev, ev2; - edge_iterator ei; /* Nothing to do if there is not at least two incoming edges. */ if (EDGE_COUNT (bb->preds) < 2) @@ -1830,19 +2105,12 @@ try_crossjump_bb (int mode, basic_block bb) if (EDGE_COUNT (bb->preds) > max) return false; - FOR_EACH_EDGE (e, ei, bb->preds) - { - if (e->flags & EDGE_FALLTHRU) - { - fallthru = e; - break; - } - } + fallthru = find_fallthru_edge (bb->preds); changed = false; - for (ix = 0, ev = bb; ix < EDGE_COUNT (ev->preds); ) + for (ix = 0; ix < EDGE_COUNT (bb->preds);) { - e = EDGE_PRED (ev, ix); + e = EDGE_PRED (bb, ix); ix++; /* As noted above, first try with the fallthru predecessor (or, a @@ -1856,15 +2124,14 @@ try_crossjump_bb (int mode, basic_block bb) /* If nothing changed since the last attempt, there is nothing we can do. */ if (!first_pass - && (!(df_get_bb_dirty (e->src)) - && !(df_get_bb_dirty (fallthru->src)))) + && !((e->src->flags & BB_MODIFIED) + || (fallthru->src->flags & BB_MODIFIED))) continue; - if (try_crossjump_to_edge (mode, e, fallthru)) + if (try_crossjump_to_edge (mode, e, fallthru, dir_forward)) { changed = true; ix = 0; - ev = bb; continue; } } @@ -1884,10 +2151,9 @@ try_crossjump_bb (int mode, basic_block bb) if (EDGE_SUCC (e->src, 0) != e) continue; - for (ix2 = 0, ev2 = bb; ix2 < EDGE_COUNT (ev2->preds); ) + for (ix2 = 0; ix2 < EDGE_COUNT (bb->preds); ix2++) { - e2 = EDGE_PRED (ev2, ix2); - ix2++; + e2 = EDGE_PRED (bb, ix2); if (e2 == e) continue; @@ -1906,14 +2172,15 @@ try_crossjump_bb (int mode, basic_block bb) /* If nothing changed since the last attempt, there is nothing we can do. */ if (!first_pass - && (!(df_get_bb_dirty (e->src)) - && !(df_get_bb_dirty (e2->src)))) + && !((e->src->flags & BB_MODIFIED) + || (e2->src->flags & BB_MODIFIED))) continue; - if (try_crossjump_to_edge (mode, e, e2)) + /* Both e and e2 are not fallthru edges, so we can crossjump in either + direction. */ + if (try_crossjump_to_edge (mode, e, e2, dir_both)) { changed = true; - ev2 = bb; ix = 0; break; } @@ -1926,6 +2193,313 @@ try_crossjump_bb (int mode, basic_block bb) return changed; } +/* Search the successors of BB for common insn sequences. When found, + share code between them by moving it across the basic block + boundary. Return true if any changes made. */ + +static bool +try_head_merge_bb (basic_block bb) +{ + basic_block final_dest_bb = NULL; + int max_match = INT_MAX; + edge e0; + rtx *headptr, *currptr, *nextptr; + bool changed, moveall; + unsigned ix; + rtx e0_last_head, cond, move_before; + unsigned nedges = EDGE_COUNT (bb->succs); + rtx jump = BB_END (bb); + regset live, live_union; + + /* Nothing to do if there is not at least two outgoing edges. */ + if (nedges < 2) + return false; + + /* Don't crossjump if this block ends in a computed jump, + unless we are optimizing for size. */ + if (optimize_bb_for_size_p (bb) + && bb != EXIT_BLOCK_PTR + && computed_jump_p (BB_END (bb))) + return false; + + cond = get_condition (jump, &move_before, true, false); + if (cond == NULL_RTX) + { +#ifdef HAVE_cc0 + if (reg_mentioned_p (cc0_rtx, jump)) + move_before = prev_nonnote_nondebug_insn (jump); + else +#endif + move_before = jump; + } + + for (ix = 0; ix < nedges; ix++) + if (EDGE_SUCC (bb, ix)->dest == EXIT_BLOCK_PTR) + return false; + + for (ix = 0; ix < nedges; ix++) + { + edge e = EDGE_SUCC (bb, ix); + basic_block other_bb = e->dest; + + if (df_get_bb_dirty (other_bb)) + { + block_was_dirty = true; + return false; + } + + if (e->flags & EDGE_ABNORMAL) + return false; + + /* Normally, all destination blocks must only be reachable from this + block, i.e. they must have one incoming edge. + + There is one special case we can handle, that of multiple consecutive + jumps where the first jumps to one of the targets of the second jump. + This happens frequently in switch statements for default labels. + The structure is as follows: + FINAL_DEST_BB + .... + if (cond) jump A; + fall through + BB + jump with targets A, B, C, D... + A + has two incoming edges, from FINAL_DEST_BB and BB + + In this case, we can try to move the insns through BB and into + FINAL_DEST_BB. */ + if (EDGE_COUNT (other_bb->preds) != 1) + { + edge incoming_edge, incoming_bb_other_edge; + edge_iterator ei; + + if (final_dest_bb != NULL + || EDGE_COUNT (other_bb->preds) != 2) + return false; + + /* We must be able to move the insns across the whole block. */ + move_before = BB_HEAD (bb); + while (!NONDEBUG_INSN_P (move_before)) + move_before = NEXT_INSN (move_before); + + if (EDGE_COUNT (bb->preds) != 1) + return false; + incoming_edge = EDGE_PRED (bb, 0); + final_dest_bb = incoming_edge->src; + if (EDGE_COUNT (final_dest_bb->succs) != 2) + return false; + FOR_EACH_EDGE (incoming_bb_other_edge, ei, final_dest_bb->succs) + if (incoming_bb_other_edge != incoming_edge) + break; + if (incoming_bb_other_edge->dest != other_bb) + return false; + } + } + + e0 = EDGE_SUCC (bb, 0); + e0_last_head = NULL_RTX; + changed = false; + + for (ix = 1; ix < nedges; ix++) + { + edge e = EDGE_SUCC (bb, ix); + rtx e0_last, e_last; + int nmatch; + + nmatch = flow_find_head_matching_sequence (e0->dest, e->dest, + &e0_last, &e_last, 0); + if (nmatch == 0) + return false; + + if (nmatch < max_match) + { + max_match = nmatch; + e0_last_head = e0_last; + } + } + + /* If we matched an entire block, we probably have to avoid moving the + last insn. */ + if (max_match > 0 + && e0_last_head == BB_END (e0->dest) + && (find_reg_note (e0_last_head, REG_EH_REGION, 0) + || control_flow_insn_p (e0_last_head))) + { + max_match--; + if (max_match == 0) + return false; + do + e0_last_head = prev_real_insn (e0_last_head); + while (DEBUG_INSN_P (e0_last_head)); + } + + if (max_match == 0) + return false; + + /* We must find a union of the live registers at each of the end points. */ + live = BITMAP_ALLOC (NULL); + live_union = BITMAP_ALLOC (NULL); + + currptr = XNEWVEC (rtx, nedges); + headptr = XNEWVEC (rtx, nedges); + nextptr = XNEWVEC (rtx, nedges); + + for (ix = 0; ix < nedges; ix++) + { + int j; + basic_block merge_bb = EDGE_SUCC (bb, ix)->dest; + rtx head = BB_HEAD (merge_bb); + + while (!NONDEBUG_INSN_P (head)) + head = NEXT_INSN (head); + headptr[ix] = head; + currptr[ix] = head; + + /* Compute the end point and live information */ + for (j = 1; j < max_match; j++) + do + head = NEXT_INSN (head); + while (!NONDEBUG_INSN_P (head)); + simulate_backwards_to_point (merge_bb, live, head); + IOR_REG_SET (live_union, live); + } + + /* If we're moving across two blocks, verify the validity of the + first move, then adjust the target and let the loop below deal + with the final move. */ + if (final_dest_bb != NULL) + { + rtx move_upto; + + moveall = can_move_insns_across (currptr[0], e0_last_head, move_before, + jump, e0->dest, live_union, + NULL, &move_upto); + if (!moveall) + { + if (move_upto == NULL_RTX) + goto out; + + while (e0_last_head != move_upto) + { + df_simulate_one_insn_backwards (e0->dest, e0_last_head, + live_union); + e0_last_head = PREV_INSN (e0_last_head); + } + } + if (e0_last_head == NULL_RTX) + goto out; + + jump = BB_END (final_dest_bb); + cond = get_condition (jump, &move_before, true, false); + if (cond == NULL_RTX) + { +#ifdef HAVE_cc0 + if (reg_mentioned_p (cc0_rtx, jump)) + move_before = prev_nonnote_nondebug_insn (jump); + else +#endif + move_before = jump; + } + } + + do + { + rtx move_upto; + moveall = can_move_insns_across (currptr[0], e0_last_head, + move_before, jump, e0->dest, live_union, + NULL, &move_upto); + if (!moveall && move_upto == NULL_RTX) + { + if (jump == move_before) + break; + + /* Try again, using a different insertion point. */ + move_before = jump; + +#ifdef HAVE_cc0 + /* Don't try moving before a cc0 user, as that may invalidate + the cc0. */ + if (reg_mentioned_p (cc0_rtx, jump)) + break; +#endif + + continue; + } + + if (final_dest_bb && !moveall) + /* We haven't checked whether a partial move would be OK for the first + move, so we have to fail this case. */ + break; + + changed = true; + for (;;) + { + if (currptr[0] == move_upto) + break; + for (ix = 0; ix < nedges; ix++) + { + rtx curr = currptr[ix]; + do + curr = NEXT_INSN (curr); + while (!NONDEBUG_INSN_P (curr)); + currptr[ix] = curr; + } + } + + /* If we can't currently move all of the identical insns, remember + each insn after the range that we'll merge. */ + if (!moveall) + for (ix = 0; ix < nedges; ix++) + { + rtx curr = currptr[ix]; + do + curr = NEXT_INSN (curr); + while (!NONDEBUG_INSN_P (curr)); + nextptr[ix] = curr; + } + + reorder_insns (headptr[0], currptr[0], PREV_INSN (move_before)); + df_set_bb_dirty (EDGE_SUCC (bb, 0)->dest); + if (final_dest_bb != NULL) + df_set_bb_dirty (final_dest_bb); + df_set_bb_dirty (bb); + for (ix = 1; ix < nedges; ix++) + { + df_set_bb_dirty (EDGE_SUCC (bb, ix)->dest); + delete_insn_chain (headptr[ix], currptr[ix], false); + } + if (!moveall) + { + if (jump == move_before) + break; + + /* For the unmerged insns, try a different insertion point. */ + move_before = jump; + +#ifdef HAVE_cc0 + /* Don't try moving before a cc0 user, as that may invalidate + the cc0. */ + if (reg_mentioned_p (cc0_rtx, jump)) + break; +#endif + + for (ix = 0; ix < nedges; ix++) + currptr[ix] = headptr[ix] = nextptr[ix]; + } + } + while (!moveall); + + out: + free (currptr); + free (headptr); + free (nextptr); + + crossjumps_occured |= changed; + + return changed; +} + /* Return true if BB contains just bb note, or bb note followed by only DEBUG_INSNs. */ @@ -1971,6 +2545,7 @@ try_optimize_cfg (int mode) one predecessor, they may be combined. */ do { + block_was_dirty = false; changed = false; iterations++; @@ -1999,28 +2574,43 @@ try_optimize_cfg (int mode) && single_succ_edge (ENTRY_BLOCK_PTR)->dest != b)) { c = b->prev_bb; - if ((mode & CLEANUP_CFGLAYOUT) - && EDGE_COUNT (b->preds) > 0 - && b->il.rtl->footer - && BARRIER_P (b->il.rtl->footer)) + if (EDGE_COUNT (b->preds) > 0) { edge e; edge_iterator ei; - FOR_EACH_EDGE (e, ei, b->preds) - if (e->flags & EDGE_FALLTHRU) - { - if (e->src->il.rtl->footer == NULL) - { - e->src->il.rtl->footer = b->il.rtl->footer; - b->il.rtl->footer = NULL; - } - break; - } + if (current_ir_type () == IR_RTL_CFGLAYOUT) + { + if (b->il.rtl->footer + && BARRIER_P (b->il.rtl->footer)) + FOR_EACH_EDGE (e, ei, b->preds) + if ((e->flags & EDGE_FALLTHRU) + && e->src->il.rtl->footer == NULL) + { + if (b->il.rtl->footer) + { + e->src->il.rtl->footer = b->il.rtl->footer; + b->il.rtl->footer = NULL; + } + else + { + start_sequence (); + e->src->il.rtl->footer = emit_barrier (); + end_sequence (); + } + } + } + else + { + rtx last = get_last_bb_insn (b); + if (last && BARRIER_P (last)) + FOR_EACH_EDGE (e, ei, b->preds) + if ((e->flags & EDGE_FALLTHRU)) + emit_barrier_after (BB_END (e->src)); + } } delete_basic_block (b); - if (!(mode & CLEANUP_CFGLAYOUT)) - changed = true; + changed = true; /* Avoid trying to remove ENTRY_BLOCK_PTR. */ b = (c == ENTRY_BLOCK_PTR ? c->next_bb : c); continue; @@ -2086,6 +2676,7 @@ try_optimize_cfg (int mode) continue; } + /* Merge B with its single successor, if any. */ if (single_succ_p (b) && (s = single_succ_edge (b)) && !(s->flags & EDGE_COMPLEX) @@ -2146,13 +2737,23 @@ try_optimize_cfg (int mode) /* Simplify branch to branch. */ if (try_forward_edges (mode, b)) - changed_here = true; + { + update_forwarder_flag (b); + changed_here = true; + } /* Look for shared code between blocks. */ if ((mode & CLEANUP_CROSSJUMP) && try_crossjump_bb (mode, b)) changed_here = true; + if ((mode & CLEANUP_CROSSJUMP) + /* This can lengthen register lifetimes. Do it only after + reload. */ + && reload_completed + && try_head_merge_bb (b)) + changed_here = true; + /* Don't get confused by the index shift caused by deleting blocks. */ if (!changed_here) @@ -2165,6 +2766,13 @@ try_optimize_cfg (int mode) && try_crossjump_bb (mode, EXIT_BLOCK_PTR)) changed = true; + if (block_was_dirty) + { + /* This should only be set by head-merging. */ + gcc_assert (mode & CLEANUP_CROSSJUMP); + df_analyze (); + } + #ifdef ENABLE_CHECKING if (changed) verify_flow_info (); @@ -2349,8 +2957,7 @@ cleanup_cfg (int mode) if ((mode & CLEANUP_EXPENSIVE) && !reload_completed && !delete_trivially_dead_insns (get_insns (), max_reg_num ())) break; - else if ((mode & CLEANUP_CROSSJUMP) - && crossjumps_occured) + if ((mode & CLEANUP_CROSSJUMP) && crossjumps_occured) run_fast_dce (); } else @@ -2429,8 +3036,6 @@ struct rtl_opt_pass pass_jump2 = 0, /* properties_provided */ 0, /* properties_destroyed */ TODO_ggc_collect, /* todo_flags_start */ - TODO_dump_func | TODO_verify_rtl_sharing,/* todo_flags_finish */ + TODO_verify_rtl_sharing, /* todo_flags_finish */ } }; - -