diff options
| -rw-r--r-- | gcc/ChangeLog | 21 | ||||
| -rw-r--r-- | gcc/cfglayout.c | 2 | ||||
| -rw-r--r-- | gcc/cfgloop.h | 10 | ||||
| -rw-r--r-- | gcc/cfgrtl.c | 10 | ||||
| -rw-r--r-- | gcc/final.c | 2 | ||||
| -rw-r--r-- | gcc/insn-notes.def | 5 | ||||
| -rw-r--r-- | gcc/jump.c | 4 | ||||
| -rw-r--r-- | gcc/loop.c | 91 | ||||
| -rw-r--r-- | gcc/reorg.c | 10 | ||||
| -rw-r--r-- | gcc/unroll.c | 202 |
10 files changed, 32 insertions, 325 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cdd2deb..1c2abb0 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,6 +1,25 @@ +2004-04-25 Paolo Bonzini <bonzini@gnu.org> + + * cfglayout.c (duplicate_insn_chain): Remove references to + NOTE_INSN_LOOP_VTOP and NOTE_INSN_LOOP_CONT. + * cfgloop.h (struct loop): Remove fields vtop, cont and cont_dominator. + * cfgrtl.c (rtl_delete_block): Remove handling of NOTE_INSN_LOOP_CONT. + * final.c (final_scan_insn): Remove references to NOTE_INSN_LOOP_VTOP + and NOTE_INSN_LOOP_CONT. + * insn-notes.def (NOTE_INSN_LOOP_VTOP, NOTE_INSN_LOOP_CONT): Remove. + * jump.c (squeeze_notes): Remove references to NOTE_INSN_LOOP_VTOP + and NOTE_INSN_LOOP_CONT. + * loop.c (scan_loops, find_and_verify_loops, for_each_insn_in_loop, + check_dbra_loop, loop_dump_aux): Remove references to removed notes + and fields. + * reorg.c (mostly_true_jump): Do not rely on NOTE_INSN_LOOP_VTOPs. + * unroll.c (unroll_loop, copy_loop_body, loop_iterations): Remove + references to removed notes and fields. + (subtract_reg_term, ujump_to_loop_cont): Remove. + 2004-08-25 Paolo Bonzini <bonzini@gnu.org> - * doc/invoke.texi: Document that libcpp does not require + * doc/install.texi: Document that libcpp does not require Automake any longer. Document that Automake 1.9.1 should work everywhere. diff --git a/gcc/cfglayout.c b/gcc/cfglayout.c index 42acec3..3971806 100644 --- a/gcc/cfglayout.c +++ b/gcc/cfglayout.c @@ -1039,8 +1039,6 @@ duplicate_insn_chain (rtx from, rtx to) in first BB, we may want to copy the block. */ case NOTE_INSN_PROLOGUE_END: - case NOTE_INSN_LOOP_VTOP: - case NOTE_INSN_LOOP_CONT: case NOTE_INSN_LOOP_BEG: case NOTE_INSN_LOOP_END: /* Strip down the loop notes - we don't really want to keep diff --git a/gcc/cfgloop.h b/gcc/cfgloop.h index 367851e..3dce20a 100644 --- a/gcc/cfgloop.h +++ b/gcc/cfgloop.h @@ -135,16 +135,6 @@ struct loop /* The following are currently used by loop.c but they are likely to disappear as loop.c is converted to use the CFG. */ - /* Nonzero if the loop has a NOTE_INSN_LOOP_VTOP. */ - rtx vtop; - - /* Nonzero if the loop has a NOTE_INSN_LOOP_CONT. - A continue statement will generate a branch to NEXT_INSN (cont). */ - rtx cont; - - /* The dominator of cont. */ - rtx cont_dominator; - /* The NOTE_INSN_LOOP_BEG. */ rtx start; diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c index d4136d2..c4cb012 100644 --- a/gcc/cfgrtl.c +++ b/gcc/cfgrtl.c @@ -376,16 +376,6 @@ rtl_delete_block (basic_block b) and remove the associated NOTE_INSN_EH_REGION_BEG and NOTE_INSN_EH_REGION_END notes. */ - /* Get rid of all NOTE_INSN_LOOP_CONTs hanging before the block. */ - - for (insn = PREV_INSN (BB_HEAD (b)); insn; insn = PREV_INSN (insn)) - { - if (!NOTE_P (insn)) - break; - if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT) - NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; - } - insn = BB_HEAD (b); if (LABEL_P (insn)) diff --git a/gcc/final.c b/gcc/final.c index 5b67678..fe4eaa6 100644 --- a/gcc/final.c +++ b/gcc/final.c @@ -1699,8 +1699,6 @@ final_scan_insn (rtx insn, FILE *file, int optimize ATTRIBUTE_UNUSED, case NOTE_INSN_DELETED: case NOTE_INSN_LOOP_BEG: case NOTE_INSN_LOOP_END: - case NOTE_INSN_LOOP_CONT: - case NOTE_INSN_LOOP_VTOP: case NOTE_INSN_FUNCTION_END: case NOTE_INSN_REPEATED_LINE_NUMBER: case NOTE_INSN_EXPECTED_VALUE: diff --git a/gcc/insn-notes.def b/gcc/insn-notes.def index 44dbb20..9571205 100644 --- a/gcc/insn-notes.def +++ b/gcc/insn-notes.def @@ -47,11 +47,6 @@ INSN_NOTE (BLOCK_END) INSN_NOTE (LOOP_BEG) INSN_NOTE (LOOP_END) -/* Generated at the place in a loop that `continue' jumps to. */ -INSN_NOTE (LOOP_CONT) -/* Generated at the start of a duplicated exit test. */ -INSN_NOTE (LOOP_VTOP) - /* This note indicates the start of the real body of the function, i.e. the point just after all of the parms have been moved into their homes, etc. */ @@ -246,9 +246,7 @@ squeeze_notes (rtx* startp, rtx* endp) && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG - || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END - || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_CONT - || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP)) + || NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)) { if (insn == start) start = next; @@ -644,8 +644,6 @@ scan_loop (struct loop *loop, int flags) since in that case saving an insn makes more difference and more registers are available. */ int threshold; - /* Nonzero if we are scanning instructions in a sub-loop. */ - int loop_depth = 0; int in_libcall; loop->top = 0; @@ -738,13 +736,8 @@ scan_loop (struct loop *loop, int flags) insn_count = count_insns_in_loop (loop); if (loop_dump_stream) - { - fprintf (loop_dump_stream, "\nLoop from %d to %d: %d real insns.\n", - INSN_UID (loop_start), INSN_UID (loop_end), insn_count); - if (loop->cont) - fprintf (loop_dump_stream, "Continue at insn %d.\n", - INSN_UID (loop->cont)); - } + fprintf (loop_dump_stream, "\nLoop from %d to %d: %d real insns.\n", + INSN_UID (loop_start), INSN_UID (loop_end), insn_count); /* Scan through the loop finding insns that are safe to move. Set REGS->ARRAY[I].SET_IN_LOOP negative for the reg I being set, so that @@ -1120,18 +1113,6 @@ scan_loop (struct loop *loop, int flags) && NEXT_INSN (NEXT_INSN (p)) == loop_end && any_uncondjump_p (p))) maybe_never = 1; - else if (NOTE_P (p)) - { - /* At the virtual top of a converted loop, insns are again known to - be executed: logically, the loop begins here even though the exit - code has been duplicated. */ - if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_VTOP && loop_depth == 0) - maybe_never = call_passed = 0; - else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG) - loop_depth++; - else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END) - loop_depth--; - } } /* If one movable subsumes another, ignore that other. */ @@ -2501,7 +2482,7 @@ count_nonfixed_reads (const struct loop *loop, rtx x) return value; } -/* Scan a loop setting the elements `cont', `vtop', `loops_enclosed', +/* Scan a loop setting the elements `loops_enclosed', `has_call', `has_nonconst_call', `has_volatile', `has_tablejump', `unknown_address_altered', `unknown_constant_address_altered', and `num_mem_sets' in LOOP. Also, fill in the array `mems' and the @@ -2741,14 +2722,6 @@ find_and_verify_loops (rtx f, struct loops *loops) current_loop = next_loop; break; - case NOTE_INSN_LOOP_CONT: - current_loop->cont = insn; - break; - - case NOTE_INSN_LOOP_VTOP: - current_loop->vtop = insn; - break; - case NOTE_INSN_LOOP_END: if (! current_loop) abort (); @@ -4276,7 +4249,6 @@ for_each_insn_in_loop (struct loop *loop, loop_insn_callback fncall) int not_every_iteration = 0; int maybe_multiple = 0; int past_loop_latch = 0; - int loop_depth = 0; rtx p; /* If loop_scan_start points to the loop exit test, we have to be wary of @@ -4359,24 +4331,6 @@ for_each_insn_in_loop (struct loop *loop, loop_insn_callback fncall) not_every_iteration = 1; } - else if (NOTE_P (p)) - { - /* At the virtual top of a converted loop, insns are again known to - be executed each iteration: logically, the loop begins here - even though the exit code has been duplicated. - - Insns are also again known to be executed each iteration at - the LOOP_CONT note. */ - if ((NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_VTOP - || NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_CONT) - && loop_depth == 0) - not_every_iteration = 0; - else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_BEG) - loop_depth++; - else if (NOTE_LINE_NUMBER (p) == NOTE_INSN_LOOP_END) - loop_depth--; - } - /* Note if we pass a loop latch. If we do, then we can not clear NOT_EVERY_ITERATION below when we pass the last CODE_LABEL in a loop since a jump before the last CODE_LABEL may have started @@ -4402,8 +4356,7 @@ for_each_insn_in_loop (struct loop *loop, loop_insn_callback fncall) if (not_every_iteration && !past_loop_latch && LABEL_P (p) - && no_labels_between_p (p, loop->end) - && loop_insn_first_p (p, loop->cont)) + && no_labels_between_p (p, loop->end)) not_every_iteration = 0; } } @@ -7990,8 +7943,8 @@ check_dbra_loop (struct loop *loop, int insn_count) sequence and see if we've got another comparison sequence. */ rtx jump1; - if ((jump1 = prev_nonnote_insn (first_compare)) != loop->cont) - if (JUMP_P (jump1)) + if ((jump1 = prev_nonnote_insn (first_compare)) + && JUMP_P (jump1)) return 0; } @@ -8304,17 +8257,6 @@ check_dbra_loop (struct loop *loop, int insn_count) /* First check if we can do a vanilla loop reversal. */ if (initial_value == const0_rtx - /* If we have a decrement_and_branch_on_count, - prefer the NE test, since this will allow that - instruction to be generated. Note that we must - use a vanilla loop reversal if the biv is used to - calculate a giv or has a non-counting use. */ -#if ! defined (HAVE_decrement_and_branch_until_zero) \ -&& defined (HAVE_decrement_and_branch_on_count) - && (! (add_val == 1 && loop->vtop - && (bl->biv_count == 0 - || no_use_except_counting))) -#endif && GET_CODE (comparison_value) == CONST_INT /* Now do postponed overflow checks on COMPARISON_VAL. */ && ! (((comparison_val - add_val) ^ INTVAL (comparison_value)) @@ -8326,13 +8268,6 @@ check_dbra_loop (struct loop *loop, int insn_count) nonneg = 1; cmp_code = GE; } - else if (add_val == 1 && loop->vtop - && (bl->biv_count == 0 - || no_use_except_counting)) - { - add_adjust = 0; - cmp_code = NE; - } else return 0; @@ -10731,15 +10666,9 @@ loop_dump_aux (const struct loop *loop, FILE *file, if (loop->start) { fprintf (file, - ";; start %d (%d), cont dom %d (%d), cont %d (%d), vtop %d (%d), end %d (%d)\n", + ";; start %d (%d), end %d (%d)\n", LOOP_BLOCK_NUM (loop->start), LOOP_INSN_UID (loop->start), - LOOP_BLOCK_NUM (loop->cont), - LOOP_INSN_UID (loop->cont), - LOOP_BLOCK_NUM (loop->cont), - LOOP_INSN_UID (loop->cont), - LOOP_BLOCK_NUM (loop->vtop), - LOOP_INSN_UID (loop->vtop), LOOP_BLOCK_NUM (loop->end), LOOP_INSN_UID (loop->end)); fprintf (file, ";; top %d (%d), scan start %d (%d)\n", @@ -10758,12 +10687,6 @@ loop_dump_aux (const struct loop *loop, FILE *file, } } fputs ("\n", file); - - /* This can happen when a marked loop appears as two nested loops, - say from while (a || b) {}. The inner loop won't match - the loop markers but the outer one will. */ - if (LOOP_BLOCK_NUM (loop->cont) != loop->latch->index) - fprintf (file, ";; NOTE_INSN_LOOP_CONT not in loop latch\n"); } } diff --git a/gcc/reorg.c b/gcc/reorg.c index dbe075a..d464a32 100644 --- a/gcc/reorg.c +++ b/gcc/reorg.c @@ -999,16 +999,6 @@ mostly_true_jump (rtx jump_insn, rtx condition) insn = PREV_INSN (insn)) if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) return 2; - - /* If this is a jump to the test of a loop, it is likely true. We scan - forwards from the target label. If we find a NOTE_INSN_LOOP_VTOP - before the next real insn, we assume the branch is to the loop branch - test. */ - for (insn = NEXT_INSN (target_label); - insn && NOTE_P (insn); - insn = PREV_INSN (insn)) - if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_VTOP) - return 1; } /* Look at the relative rarities of the fallthrough and destination. If diff --git a/gcc/unroll.c b/gcc/unroll.c index 6902002..cef4c6e 100644 --- a/gcc/unroll.c +++ b/gcc/unroll.c @@ -214,9 +214,7 @@ static int reg_dead_after_loop (const struct loop *, rtx); static rtx fold_rtx_mult_add (rtx, rtx, rtx, enum machine_mode); static rtx remap_split_bivs (struct loop *, rtx); static rtx find_common_reg_term (rtx, rtx); -static rtx subtract_reg_term (rtx, rtx); static rtx loop_find_equiv_value (const struct loop *, rtx); -static rtx ujump_to_loop_cont (rtx, rtx); /* Try to unroll one loop and split induction variables in the loop. @@ -297,16 +295,6 @@ unroll_loop (struct loop *loop, int insn_count, int strength_reduce_p) jump to the loop condition. Make sure to delete the jump insn, otherwise the loop body will never execute. */ - /* FIXME this actually checks for a jump to the continue point, which - is not the same as the condition in a for loop. As a result, this - optimization fails for most for loops. We should really use flow - information rather than instruction pattern matching. */ - rtx ujump = ujump_to_loop_cont (loop->start, loop->cont); - - /* If number of iterations is exactly 1, then eliminate the compare and - branch at the end of the loop since they will never be taken. - Then return, since no other action is needed here. */ - /* If the last instruction is not a BARRIER or a JUMP_INSN, then don't do anything. */ @@ -315,34 +303,6 @@ unroll_loop (struct loop *loop, int insn_count, int strength_reduce_p) /* Delete the jump insn. This will delete the barrier also. */ last_loop_insn = PREV_INSN (last_loop_insn); } - - if (ujump && JUMP_P (last_loop_insn)) - { -#ifdef HAVE_cc0 - rtx prev = PREV_INSN (last_loop_insn); -#endif - delete_related_insns (last_loop_insn); -#ifdef HAVE_cc0 - /* The immediately preceding insn may be a compare which must be - deleted. */ - if (only_sets_cc0_p (prev)) - delete_related_insns (prev); -#endif - - delete_related_insns (ujump); - - /* Remove the loop notes since this is no longer a loop. */ - if (loop->vtop) - delete_related_insns (loop->vtop); - if (loop->cont) - delete_related_insns (loop->cont); - if (loop_start) - delete_related_insns (loop_start); - if (loop_end) - delete_related_insns (loop_end); - - return; - } } if (loop_info->n_iterations > 0 @@ -1296,10 +1256,6 @@ unroll_loop (struct loop *loop, int insn_count, int strength_reduce_p) if (unroll_type == UNROLL_COMPLETELY) { /* Remove the loop notes since this is no longer a loop. */ - if (loop->vtop) - delete_related_insns (loop->vtop); - if (loop->cont) - delete_related_insns (loop->cont); if (loop_start) delete_related_insns (loop_start); if (loop_end) @@ -2221,19 +2177,13 @@ copy_loop_body (struct loop *loop, rtx copy_start, rtx copy_end, break; case NOTE: - /* VTOP and CONT notes are valid only before the loop exit test. - If placed anywhere else, loop may generate bad code. */ /* BASIC_BLOCK notes exist to stabilize basic block structures with the associated rtl. We do not want to share the structure in this new block. */ if (NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED_LABEL - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK - && ((NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_VTOP - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_CONT) - || (last_iteration - && unroll_type != UNROLL_COMPLETELY))) + && NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED_LABEL + && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK) copy = emit_note_copy (insn); else copy = 0; @@ -2272,17 +2222,9 @@ copy_loop_body (struct loop *loop, rtx copy_start, rtx copy_end, { for (insn = copy_notes_from; insn != loop_end; insn = NEXT_INSN (insn)) { - /* VTOP notes are valid only before the loop exit test. - If placed anywhere else, loop may generate bad code. - Although COPY_NOTES_FROM will be at most one or two (for cc0) - instructions before the last insn in the loop, COPY_NOTES_FROM - can be a NOTE_INSN_LOOP_CONT note if there is no VTOP note, - as in a do .. while loop. */ if (NOTE_P (insn) - && ((NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_VTOP - && NOTE_LINE_NUMBER (insn) != NOTE_INSN_LOOP_CONT))) + && NOTE_LINE_NUMBER (insn) != NOTE_INSN_DELETED + && NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK) emit_note_copy (insn); } } @@ -3177,32 +3119,6 @@ loop_find_equiv_value (const struct loop *loop, rtx reg) return ret; } -/* Return a simplified rtx for the expression OP - REG. - - REG must appear in OP, and OP must be a register or the sum of a register - and a second term. - - Thus, the return value must be const0_rtx or the second term. - - The caller is responsible for verifying that REG appears in OP and OP has - the proper form. */ - -static rtx -subtract_reg_term (rtx op, rtx reg) -{ - if (op == reg) - return const0_rtx; - if (GET_CODE (op) == PLUS) - { - if (XEXP (op, 0) == reg) - return XEXP (op, 1); - else if (XEXP (op, 1) == reg) - return XEXP (op, 0); - } - /* OP does not contain REG as a term. */ - abort (); -} - /* Find and return register term common to both expressions OP0 and OP1 or NULL_RTX if no such term exists. Each expression must be a REG or a PLUS of a REG. */ @@ -3258,7 +3174,6 @@ loop_iterations (struct loop *loop) int increment_dir; int unsigned_p, compare_dir, final_larger; rtx last_loop_insn; - rtx reg_term; struct iv_class *bl; loop_info->n_iterations = 0; @@ -3299,44 +3214,6 @@ loop_iterations (struct loop *loop) return 0; } - /* If there are multiple conditionalized loop exit tests, they may jump - back to differing CODE_LABELs. */ - if (loop->top && loop->cont) - { - rtx temp = PREV_INSN (last_loop_insn); - - do - { - if (JUMP_P (temp)) - { - /* There are some kinds of jumps we can't deal with easily. */ - if (JUMP_LABEL (temp) == 0) - { - if (loop_dump_stream) - fprintf - (loop_dump_stream, - "Loop iterations: Jump insn has null JUMP_LABEL.\n"); - return 0; - } - - if (/* Previous unrolling may have generated new insns not - covered by the uid_luid array. */ - INSN_UID (JUMP_LABEL (temp)) < max_uid_for_loop - /* Check if we jump back into the loop body. */ - && INSN_LUID (JUMP_LABEL (temp)) > INSN_LUID (loop->top) - && INSN_LUID (JUMP_LABEL (temp)) < INSN_LUID (loop->cont)) - { - if (loop_dump_stream) - fprintf - (loop_dump_stream, - "Loop iterations: Loop has multiple back edges.\n"); - return 0; - } - } - } - while ((temp = PREV_INSN (temp)) != loop->cont); - } - /* Find the iteration variable. If the last insn is a conditional branch, and the insn before tests a register value, make that the iteration variable. */ @@ -3650,44 +3527,6 @@ loop_iterations (struct loop *loop) ? reg1 : gen_rtx_PLUS (GET_MODE (reg1), reg1, const2); } } - else if (loop->vtop && GET_CODE (reg2) == CONST_INT) - { - rtx temp; - - /* When running the loop optimizer twice, check_dbra_loop - further obfuscates reversible loops of the form: - for (i = init; i < init + const; i++). We often end up with - final_value = 0, initial_value = temp, temp = temp2 - init, - where temp2 = init + const. If the loop has a vtop we - can replace initial_value with const. */ - - temp = loop_find_equiv_value (loop, reg1); - - if (GET_CODE (temp) == MINUS && REG_P (XEXP (temp, 0))) - { - rtx temp2 = loop_find_equiv_value (loop, XEXP (temp, 0)); - - if (GET_CODE (temp2) == PLUS - && XEXP (temp2, 0) == XEXP (temp, 1)) - initial_value = XEXP (temp2, 1); - } - } - } - - /* If have initial_value = reg + const1 and final_value = reg + - const2, then replace initial_value with const1 and final_value - with const2. This should be safe since we are protected by the - initial comparison before entering the loop if we have a vtop. - For example, a + b < a + c is not equivalent to b < c for all a - when using modulo arithmetic. - - ??? Without a vtop we could still perform the optimization if we check - the initial and final values carefully. */ - if (loop->vtop - && (reg_term = find_common_reg_term (initial_value, final_value))) - { - initial_value = subtract_reg_term (initial_value, reg_term); - final_value = subtract_reg_term (final_value, reg_term); } loop_info->initial_equiv_value = initial_value; @@ -3999,36 +3838,3 @@ set_dominates_use (int regno, int first_uid, int last_uid, rtx copy_start, return 1; } -/* This routine is called when the number of iterations for the unrolled - loop is one. The goal is to identify a loop that begins with an - unconditional branch to the loop continuation note (or a label just after). - In this case, the unconditional branch that starts the loop needs to be - deleted so that we execute the single iteration. */ - -static rtx -ujump_to_loop_cont (rtx loop_start, rtx loop_cont) -{ - rtx x, label, label_ref; - - /* See if loop start, or the next insn is an unconditional jump. */ - loop_start = next_nonnote_insn (loop_start); - - x = pc_set (loop_start); - if (!x) - return NULL_RTX; - - label_ref = SET_SRC (x); - if (!label_ref) - return NULL_RTX; - - /* Examine insn after loop continuation note. Return if not a label. */ - label = next_nonnote_insn (loop_cont); - if (label == 0 || !LABEL_P (label)) - return NULL_RTX; - - /* Return the loop start if the branch label matches the code label. */ - if (CODE_LABEL_NUMBER (label) == CODE_LABEL_NUMBER (XEXP (label_ref, 0))) - return loop_start; - else - return NULL_RTX; -} |