diff options
Diffstat (limited to 'gcc/ifcvt.c')
| -rw-r--r-- | gcc/ifcvt.c | 104 |
1 files changed, 94 insertions, 10 deletions
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index 42c5fb50bdb..31fa73b64fd 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -645,8 +645,8 @@ noce_emit_store_flag (if_info, x, reversep, normalize) end_sequence (); } - /* Don't even try if the comparison operands are weird. */ - if (cond_complex) + /* Don't even try if the comparison operands or the mode of X are weird. */ + if (cond_complex || !SCALAR_INT_MODE_P (GET_MODE (x))) return NULL_RTX; return emit_store_flag (x, code, XEXP (cond, 0), @@ -1082,6 +1082,7 @@ noce_try_cmove_arith (if_info) rtx a = if_info->a; rtx b = if_info->b; rtx x = if_info->x; + rtx orig_a, orig_b; rtx insn_a, insn_b; rtx tmp, target; int is_mem = 0; @@ -1137,6 +1138,9 @@ noce_try_cmove_arith (if_info) start_sequence (); + orig_a = a; + orig_b = b; + /* If either operand is complex, load it into a register first. The best way to do this is to copy the original insn. In this way we preserve any clobbers etc that the insn may have had. @@ -1168,7 +1172,7 @@ noce_try_cmove_arith (if_info) } if (! general_operand (b, GET_MODE (b))) { - rtx set; + rtx set, last; if (no_new_pseudos) goto end_seq_and_fail; @@ -1176,9 +1180,18 @@ noce_try_cmove_arith (if_info) if (is_mem) { tmp = gen_reg_rtx (GET_MODE (b)); - tmp = emit_insn (gen_rtx_SET (VOIDmode, tmp, b)); + tmp = gen_rtx_SET (VOIDmode, tmp, b); } - else if (! insn_b) + else if (! insn_b +#if 0 + /* In the case we are going to duplicate insn originally + present in the front of comparsion, verify that the + comparsion didn't clobbered the operands. */ + || modified_between_p (SET_SRC (single_set (insn_b)), + if_info->cond_earliest, + NEXT_INSN (if_info->jump))) +#endif + ) goto end_seq_and_fail; else { @@ -1186,8 +1199,22 @@ noce_try_cmove_arith (if_info) tmp = copy_rtx (insn_b); set = single_set (tmp); SET_DEST (set) = b; - tmp = emit_insn (PATTERN (tmp)); + tmp = PATTERN (tmp); + } + + /* If insn to set up A clobbers any registers B depends on, try to + swap insn that sets up A with the one that sets up B. If even + that doesn't help, punt. */ + last = get_last_insn (); + if (last && modified_in_p (orig_b, last)) + { + tmp = emit_insn_before (tmp, get_insns ()); + if (modified_in_p (orig_a, tmp)) + goto end_seq_and_fail; } + else + tmp = emit_insn (tmp); + if (recog_memoized (tmp) < 0) goto end_seq_and_fail; } @@ -1770,16 +1797,33 @@ noce_process_if_block (ce_info) else { insn_b = prev_nonnote_insn (if_info.cond_earliest); + /* We're going to be moving the evaluation of B down from above + COND_EARLIEST to JUMP. Make sure the relevant data is still + intact. */ if (! insn_b || GET_CODE (insn_b) != INSN || (set_b = single_set (insn_b)) == NULL_RTX || ! rtx_equal_p (x, SET_DEST (set_b)) + || reg_overlap_mentioned_p (x, SET_SRC (set_b)) + || modified_between_p (SET_SRC (set_b), + PREV_INSN (if_info.cond_earliest), jump) + /* Likewise with X. In particular this can happen when + noce_get_condition looks farther back in the instruction + stream than one might expect. */ || reg_overlap_mentioned_p (x, cond) || reg_overlap_mentioned_p (x, a) - || reg_overlap_mentioned_p (x, SET_SRC (set_b)) - || modified_between_p (x, if_info.cond_earliest, NEXT_INSN (jump))) + || modified_between_p (x, PREV_INSN (if_info.cond_earliest), jump)) insn_b = set_b = NULL_RTX; } + + /* If x has side effects then only the if-then-else form is safe to + convert. But even in that case we would need to restore any notes + (such as REG_INC) at then end. That can be tricky if + noce_emit_move_insn expands to more than one insn, so disable the + optimization entirely for now if there are side effects. */ + if (side_effects_p (x)) + return FALSE; + b = (set_b ? SET_SRC (set_b) : x); /* Only operate on register destinations, and even then avoid extending @@ -1845,6 +1889,25 @@ noce_process_if_block (ce_info) goto success; } + /* Disallow the "if (...) x = a;" form (with an implicit "else x = x;") + for most optimizations if writing to x may trap, i.e. its a memory + other than a static var or a stack slot. */ + if (! set_b + && GET_CODE (orig_x) == MEM + && ! MEM_NOTRAP_P (orig_x) + && rtx_addr_can_trap_p (XEXP (orig_x, 0))) + { + if (HAVE_conditional_move) + { + if (noce_try_cmove (&if_info)) + goto success; + if (! HAVE_conditional_execution + && noce_try_cmove_arith (&if_info)) + goto success; + } + return FALSE; + } + if (noce_try_store_flag (&if_info)) goto success; if (noce_try_minmax (&if_info)) @@ -2325,7 +2388,8 @@ find_if_block (ce_info) /* The THEN block of an IF-THEN combo must have zero or one successors. */ if (then_succ != NULL_EDGE && (then_succ->succ_next != NULL_EDGE - || (then_succ->flags & EDGE_COMPLEX))) + || (then_succ->flags & EDGE_COMPLEX) + || (flow2_completed && tablejump_p (then_bb->end)))) return FALSE; /* If the THEN block has no successors, conditional execution can still @@ -2372,7 +2436,8 @@ find_if_block (ce_info) && then_succ->dest == else_succ->dest && else_bb->pred->pred_next == NULL_EDGE && else_succ->succ_next == NULL_EDGE - && ! (else_succ->flags & EDGE_COMPLEX)) + && ! (else_succ->flags & EDGE_COMPLEX) + && ! (flow2_completed && tablejump_p (else_bb->end))) join_bb = else_succ->dest; /* Otherwise it is not an IF-THEN or IF-THEN-ELSE combination. */ @@ -2701,6 +2766,8 @@ find_if_case_1 (test_bb, then_edge, else_edge) { new_bb->index = then_bb_index; BASIC_BLOCK (then_bb_index) = new_bb; + if (post_dominators) + add_to_dominance_info (post_dominators, new_bb); } /* We've possibly created jump to next insn, cleanup_cfg will solve that later. */ @@ -2831,11 +2898,28 @@ dead_or_predicable (test_bb, merge_bb, other_bb, new_dest, reversep) if (GET_CODE (end) == JUMP_INSN) { + rtx tmp, insn, label; + if (head == end) { head = end = NULL_RTX; goto no_body; } + + /* If there is a jump table following merge_bb, fail + if there are any insn between head and PREV_INSN (end) + references it. */ + if ((label = JUMP_LABEL (end)) != NULL_RTX + && (tmp = NEXT_INSN (label)) != NULL_RTX + && GET_CODE (tmp) == JUMP_INSN + && (GET_CODE (PATTERN (tmp)) == ADDR_VEC + || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) + { + for (insn = head; insn != PREV_INSN (end); insn = NEXT_INSN (insn)) + if (find_reg_note (insn, REG_LABEL, label)) + return FALSE; + } + end = PREV_INSN (end); } |