diff options
Diffstat (limited to 'gcc/jump.c')
| -rw-r--r-- | gcc/jump.c | 361 |
1 files changed, 2 insertions, 359 deletions
diff --git a/gcc/jump.c b/gcc/jump.c index 643a714c7ad..2b46f7bc991 100644 --- a/gcc/jump.c +++ b/gcc/jump.c @@ -63,10 +63,8 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA or even change what is live at any point. So perhaps let combiner do it. */ -static rtx next_nonnote_insn_in_loop (rtx); static void init_label_info (rtx); static void mark_all_labels (rtx); -static int duplicate_loop_exit_test (rtx); static void delete_computation (rtx); static void redirect_exp_1 (rtx *, rtx, rtx, rtx); static int redirect_exp (rtx, rtx, rtx); @@ -122,55 +120,6 @@ cleanup_barriers (void) } } } - -/* Return the next insn after INSN that is not a NOTE and is in the loop, - i.e. when there is no such INSN before NOTE_INSN_LOOP_END return NULL_RTX. - This routine does not look inside SEQUENCEs. */ - -static rtx -next_nonnote_insn_in_loop (rtx insn) -{ - while (insn) - { - insn = NEXT_INSN (insn); - if (insn == 0 || GET_CODE (insn) != NOTE) - break; - if (GET_CODE (insn) == NOTE - && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) - return NULL_RTX; - } - - return insn; -} - -void -copy_loop_headers (rtx f) -{ - rtx insn, next; - /* Now iterate optimizing jumps until nothing changes over one pass. */ - for (insn = f; insn; insn = next) - { - rtx temp, temp1; - - next = NEXT_INSN (insn); - - /* See if this is a NOTE_INSN_LOOP_BEG followed by an unconditional - jump. Try to optimize by duplicating the loop exit test if so. - This is only safe immediately after regscan, because it uses - the values of regno_first_uid and regno_last_uid. */ - if (GET_CODE (insn) == NOTE - && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG - && (temp1 = next_nonnote_insn_in_loop (insn)) != 0 - && any_uncondjump_p (temp1) && onlyjump_p (temp1)) - { - temp = PREV_INSN (insn); - if (duplicate_loop_exit_test (insn)) - { - next = NEXT_INSN (temp); - } - } - } -} void purge_line_number_notes (rtx f) @@ -287,245 +236,6 @@ mark_all_labels (rtx f) } } } - -/* LOOP_START is a NOTE_INSN_LOOP_BEG note that is followed by an unconditional - jump. Assume that this unconditional jump is to the exit test code. If - the code is sufficiently simple, make a copy of it before INSN, - followed by a jump to the exit of the loop. Then delete the unconditional - jump after INSN. - - Return 1 if we made the change, else 0. - - This is only safe immediately after a regscan pass because it uses the - values of regno_first_uid and regno_last_uid. */ - -static int -duplicate_loop_exit_test (rtx loop_start) -{ - rtx insn, set, reg, p, link; - rtx copy = 0, first_copy = 0; - int num_insns = 0; - rtx exitcode - = NEXT_INSN (JUMP_LABEL (next_nonnote_insn_in_loop (loop_start))); - rtx lastexit; - int max_reg = max_reg_num (); - rtx *reg_map = 0; - rtx loop_pre_header_label; - - /* Scan the exit code. We do not perform this optimization if any insn: - - is a CALL_INSN - is a CODE_LABEL - has a REG_RETVAL or REG_LIBCALL note (hard to adjust) - is a NOTE_INSN_LOOP_BEG because this means we have a nested loop - - We also do not do this if we find an insn with ASM_OPERANDS. While - this restriction should not be necessary, copying an insn with - ASM_OPERANDS can confuse asm_noperands in some cases. - - Also, don't do this if the exit code is more than 20 insns. */ - - for (insn = exitcode; - insn - && ! (GET_CODE (insn) == NOTE - && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END); - insn = NEXT_INSN (insn)) - { - switch (GET_CODE (insn)) - { - case CODE_LABEL: - case CALL_INSN: - return 0; - case NOTE: - - if (optimize < 2 - && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG - || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END)) - /* If we were to duplicate this code, we would not move - the BLOCK notes, and so debugging the moved code would - be difficult. Thus, we only move the code with -O2 or - higher. */ - return 0; - - break; - case JUMP_INSN: - case INSN: - if (++num_insns > 20 - || find_reg_note (insn, REG_RETVAL, NULL_RTX) - || find_reg_note (insn, REG_LIBCALL, NULL_RTX)) - return 0; - break; - default: - break; - } - } - - /* Unless INSN is zero, we can do the optimization. */ - if (insn == 0) - return 0; - - lastexit = insn; - - /* See if any insn sets a register only used in the loop exit code and - not a user variable. If so, replace it with a new register. */ - for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn)) - if (GET_CODE (insn) == INSN - && (set = single_set (insn)) != 0 - && ((reg = SET_DEST (set), GET_CODE (reg) == REG) - || (GET_CODE (reg) == SUBREG - && (reg = SUBREG_REG (reg), GET_CODE (reg) == REG))) - && REGNO (reg) >= FIRST_PSEUDO_REGISTER - && REGNO_FIRST_UID (REGNO (reg)) == INSN_UID (insn)) - { - for (p = NEXT_INSN (insn); p != lastexit; p = NEXT_INSN (p)) - if (REGNO_LAST_UID (REGNO (reg)) == INSN_UID (p)) - break; - - if (p != lastexit) - { - /* We can do the replacement. Allocate reg_map if this is the - first replacement we found. */ - if (reg_map == 0) - reg_map = xcalloc (max_reg, sizeof (rtx)); - - REG_LOOP_TEST_P (reg) = 1; - - reg_map[REGNO (reg)] = gen_reg_rtx (GET_MODE (reg)); - } - } - loop_pre_header_label = gen_label_rtx (); - - /* Now copy each insn. */ - for (insn = exitcode; insn != lastexit; insn = NEXT_INSN (insn)) - { - switch (GET_CODE (insn)) - { - case BARRIER: - copy = emit_barrier_before (loop_start); - break; - case NOTE: - /* Only copy line-number notes. */ - if (NOTE_LINE_NUMBER (insn) >= 0) - { - copy = emit_note_before (NOTE_LINE_NUMBER (insn), loop_start); - NOTE_SOURCE_FILE (copy) = NOTE_SOURCE_FILE (insn); - } - break; - - case INSN: - copy = emit_insn_before (copy_insn (PATTERN (insn)), loop_start); - if (reg_map) - replace_regs (PATTERN (copy), reg_map, max_reg, 1); - - mark_jump_label (PATTERN (copy), copy, 0); - INSN_LOCATOR (copy) = INSN_LOCATOR (insn); - - /* Copy all REG_NOTES except REG_LABEL since mark_jump_label will - make them. */ - for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) - if (REG_NOTE_KIND (link) != REG_LABEL) - { - if (GET_CODE (link) == EXPR_LIST) - REG_NOTES (copy) - = copy_insn_1 (gen_rtx_EXPR_LIST (REG_NOTE_KIND (link), - XEXP (link, 0), - REG_NOTES (copy))); - else - REG_NOTES (copy) - = copy_insn_1 (gen_rtx_INSN_LIST (REG_NOTE_KIND (link), - XEXP (link, 0), - REG_NOTES (copy))); - } - - if (reg_map && REG_NOTES (copy)) - replace_regs (REG_NOTES (copy), reg_map, max_reg, 1); - break; - - case JUMP_INSN: - copy = emit_jump_insn_before (copy_insn (PATTERN (insn)), - loop_start); - INSN_LOCATOR (copy) = INSN_LOCATOR (insn); - if (reg_map) - replace_regs (PATTERN (copy), reg_map, max_reg, 1); - mark_jump_label (PATTERN (copy), copy, 0); - if (REG_NOTES (insn)) - { - REG_NOTES (copy) = copy_insn_1 (REG_NOTES (insn)); - if (reg_map) - replace_regs (REG_NOTES (copy), reg_map, max_reg, 1); - } - - /* Predict conditional jump that do make loop looping as taken. - Other jumps are probably exit conditions, so predict - them as untaken. */ - if (any_condjump_p (copy)) - { - rtx label = JUMP_LABEL (copy); - if (label) - { - /* The jump_insn after loop_start should be followed - by barrier and loopback label. */ - if (prev_nonnote_insn (label) - && (prev_nonnote_insn (prev_nonnote_insn (label)) - == next_nonnote_insn (loop_start))) - { - predict_insn_def (copy, PRED_LOOP_HEADER, TAKEN); - /* To keep pre-header, we need to redirect all loop - entrances before the LOOP_BEG note. */ - redirect_jump (copy, loop_pre_header_label, 0); - } - else - predict_insn_def (copy, PRED_LOOP_HEADER, NOT_TAKEN); - } - } - break; - - default: - abort (); - } - - /* Record the first insn we copied. We need it so that we can - scan the copied insns for new pseudo registers. */ - if (! first_copy) - first_copy = copy; - } - - /* Now clean up by emitting a jump to the end label and deleting the jump - at the start of the loop. */ - if (! copy || GET_CODE (copy) != BARRIER) - { - copy = emit_jump_insn_before (gen_jump (get_label_after (insn)), - loop_start); - - /* Record the first insn we copied. We need it so that we can - scan the copied insns for new pseudo registers. This may not - be strictly necessary since we should have copied at least one - insn above. But I am going to be safe. */ - if (! first_copy) - first_copy = copy; - - mark_jump_label (PATTERN (copy), copy, 0); - emit_barrier_before (loop_start); - } - - emit_label_before (loop_pre_header_label, loop_start); - - /* Now scan from the first insn we copied to the last insn we copied - (copy) for new pseudo registers. Do this after the code to jump to - the end label since that might create a new pseudo too. */ - reg_scan_update (first_copy, copy, max_reg); - - /* Mark the exit code as the virtual top of the converted loop. */ - emit_note_before (NOTE_INSN_LOOP_VTOP, exitcode); - - delete_related_insns (next_nonnote_insn (loop_start)); - - /* Clean up. */ - if (reg_map) - free (reg_map); - - return 1; -} /* Move all block-beg, block-end, loop-beg, loop-cont, loop-vtop, loop-end, notes between START and END out before START. START and END may be such @@ -1143,6 +853,8 @@ any_uncondjump_p (rtx insn) return 0; if (GET_CODE (SET_SRC (x)) != LABEL_REF) return 0; + if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) + return 0; return 1; } @@ -1827,75 +1539,6 @@ delete_for_peephole (rtx from, rtx to) is also an unconditional jump in that case. */ } -/* We have determined that AVOIDED_INSN is never reached, and are - about to delete it. If the insn chain between AVOIDED_INSN and - FINISH contains more than one line from the current function, and - contains at least one operation, print a warning if the user asked - for it. If FINISH is NULL, look between AVOIDED_INSN and a LABEL. - - CSE and inlining can duplicate insns, so it's possible to get - spurious warnings from this. */ - -void -never_reached_warning (rtx avoided_insn, rtx finish) -{ - rtx insn; - rtx a_line_note = NULL; - int two_avoided_lines = 0, contains_insn = 0, reached_end = 0; - - if (!warn_notreached) - return; - - /* Back up to the first of any NOTEs preceding avoided_insn; flow passes - us the head of a block, a NOTE_INSN_BASIC_BLOCK, which often follows - the line note. */ - insn = avoided_insn; - while (1) - { - rtx prev = PREV_INSN (insn); - if (prev == NULL_RTX - || GET_CODE (prev) != NOTE) - break; - insn = prev; - } - - /* Scan forwards, looking at LINE_NUMBER notes, until we hit a LABEL - in case FINISH is NULL, otherwise until we run out of insns. */ - - for (; insn != NULL; insn = NEXT_INSN (insn)) - { - if ((finish == NULL && GET_CODE (insn) == CODE_LABEL) - || GET_CODE (insn) == BARRIER) - break; - - if (GET_CODE (insn) == NOTE /* A line number note? */ - && NOTE_LINE_NUMBER (insn) >= 0) - { - if (a_line_note == NULL) - a_line_note = insn; - else - two_avoided_lines |= (NOTE_LINE_NUMBER (a_line_note) - != NOTE_LINE_NUMBER (insn)); - } - else if (INSN_P (insn)) - { - if (reached_end) - break; - contains_insn = 1; - } - - if (insn == finish) - reached_end = 1; - } - if (two_avoided_lines && contains_insn) - { - location_t locus; - locus.file = NOTE_SOURCE_FILE (a_line_note); - locus.line = NOTE_LINE_NUMBER (a_line_note); - warning ("%Hwill never be executed", &locus); - } -} - /* Throughout LOC, redirect OLABEL to NLABEL. Treat null OLABEL or NLABEL as a return. Accrue modifications into the change group. */ |