diff options
Diffstat (limited to 'gcc/cse.c')
| -rw-r--r-- | gcc/cse.c | 75 |
1 files changed, 41 insertions, 34 deletions
@@ -269,17 +269,13 @@ struct change_cc_mode_args table since its use is guaranteed to be the insn immediately following its definition and any other insn is presumed to invalidate it. - Instead, we store below the value last assigned to CC0. If it should - happen to be a constant, it is stored in preference to the actual - assigned value. In case it is a constant, we store the mode in which - the constant should be interpreted. */ + Instead, we store below the current and last value assigned to CC0. + If it should happen to be a constant, it is stored in preference + to the actual assigned value. In case it is a constant, we store + the mode in which the constant should be interpreted. */ -static rtx prev_insn_cc0; -static enum machine_mode prev_insn_cc0_mode; - -/* Previous actual insn. 0 if at first insn of basic block. */ - -static rtx prev_insn; +static rtx this_insn_cc0, prev_insn_cc0; +static enum machine_mode this_insn_cc0_mode, prev_insn_cc0_mode; #endif /* Insn being scanned. */ @@ -900,7 +896,6 @@ new_basic_block (void) } #ifdef HAVE_cc0 - prev_insn = 0; prev_insn_cc0 = 0; #endif } @@ -4022,8 +4017,8 @@ cse_insn (rtx insn, rtx libcall_insn) #ifdef HAVE_cc0 /* Records what this insn does to set CC0. */ - rtx this_insn_cc0 = 0; - enum machine_mode this_insn_cc0_mode = VOIDmode; + this_insn_cc0 = 0; + this_insn_cc0_mode = VOIDmode; #endif rtx src_eqv = 0; @@ -5644,20 +5639,6 @@ cse_insn (rtx insn, rtx libcall_insn) } done:; -#ifdef HAVE_cc0 - /* If the previous insn set CC0 and this insn no longer references CC0, - delete the previous insn. Here we use the fact that nothing expects CC0 - to be valid over an insn, which is true until the final pass. */ - if (prev_insn && NONJUMP_INSN_P (prev_insn) - && (tem = single_set (prev_insn)) != 0 - && SET_DEST (tem) == cc0_rtx - && ! reg_mentioned_p (cc0_rtx, x)) - delete_insn_and_edges (prev_insn); - - prev_insn_cc0 = this_insn_cc0; - prev_insn_cc0_mode = this_insn_cc0_mode; - prev_insn = insn; -#endif } /* Remove from the hash table all expressions that reference memory. */ @@ -6096,19 +6077,39 @@ cse_extended_basic_block (struct cse_basic_block_data *ebb_data) && for_each_rtx (&PATTERN (insn), check_for_label_ref, (void *) insn)) recorded_label_ref = 1; + +#ifdef HAVE_cc0 + /* If the previous insn set CC0 and this insn no longer + references CC0, delete the previous insn. Here we use + fact that nothing expects CC0 to be valid over an insn, + which is true until the final pass. */ + { + rtx prev_insn, tem; + + prev_insn = PREV_INSN (insn); + if (prev_insn && NONJUMP_INSN_P (prev_insn) + && (tem = single_set (prev_insn)) != 0 + && SET_DEST (tem) == cc0_rtx + && ! reg_mentioned_p (cc0_rtx, PATTERN (insn))) + delete_insn (prev_insn); + } + + /* If this insn is not the last insn in the basic block, + it will be PREV_INSN(insn) in the next iteration. If + we recorded any CC0-related information for this insn, + remember it. */ + if (insn != BB_END (bb)) + { + prev_insn_cc0 = this_insn_cc0; + prev_insn_cc0_mode = this_insn_cc0_mode; + } +#endif } } /* Make sure that libcalls don't span multiple basic blocks. */ gcc_assert (libcall_insn == NULL_RTX); -#ifdef HAVE_cc0 - /* Clear the CC0-tracking related insns, they can't provide - useful information across basic block boundaries. */ - prev_insn_cc0 = 0; - prev_insn = 0; -#endif - /* If we changed a conditional jump, we may have terminated the path we are following. Check that by verifying that the edge we would take still exists. If the edge does @@ -6133,6 +6134,12 @@ cse_extended_basic_block (struct cse_basic_block_data *ebb_data) bool taken = (next_bb == BRANCH_EDGE (bb)->dest); record_jump_equiv (insn, taken); } + +#ifdef HAVE_cc0 + /* Clear the CC0-tracking related insns, they can't provide + useful information across basic block boundaries. */ + prev_insn_cc0 = 0; +#endif } gcc_assert (next_qty <= max_qty); |