From: steven Date: Thu, 11 Jan 2007 21:26:02 +0000 (+0000) Subject: * ifcvt.c (struct noce_if_info): Add comments to the fields. X-Git-Url: http://git.sourceforge.jp/view?p=pf3gnuchains%2Fgcc-fork.git;a=commitdiff_plain;h=5b410d6a7a6082f40ec95069ad833c08a2bbb04b;ds=sidebyside * ifcvt.c (struct noce_if_info): Add comments to the fields. Remove the b_unconditional field. (noce_try_sign_mask): Do not look at b_unconditional. (noce_process_if_block): Do not use merge_if_blocks. Update the CFG here. Do not set b_unconditional. (cond_move_process_if_block): Likewise. (find_cond_trap): Likewise. (check_cond_move_block): Require simple jump insns at the end of the basic block. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@120686 138bc75d-0d04-0410-961f-82ee72b054a4 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 753a47642e4..ba94be3fcc6 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +2007-01-11 Steven Bosscher + + * ifcvt.c (struct noce_if_info): Add comments to the fields. + Remove the b_unconditional field. + (noce_try_sign_mask): Do not look at b_unconditional. + (noce_process_if_block): Do not use merge_if_blocks. Update + the CFG here. Do not set b_unconditional. + (cond_move_process_if_block): Likewise. + (find_cond_trap): Likewise. + (check_cond_move_block): Require simple jump insns at the end + of the basic block. + 2007-01-11 Jan Hubicka PR tree-optimization/1046 diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index 553d69d26c3..74696d7f1af 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -596,12 +596,31 @@ cond_exec_process_if_block (ce_if_block_t * ce_info, struct noce_if_info { + /* A basic block that ends in a simple conditional jump. */ basic_block test_bb; + + /* The jump that ends TEST_BB. */ + rtx jump; + + /* The jump condition. */ + rtx cond; + + /* New insns should be inserted before this one. */ + rtx cond_earliest; + + /* Insns in the THEN and ELSE block. There is always just this + one insns in those blocks. The insns are single_set insns. + If there was no ELSE block, INSN_B is the last insn before + COND_EARLIEST, or NULL_RTX. In the former case, the insn + operands are still valid, as if INSN_B was moved down below + the jump. */ rtx insn_a, insn_b; - rtx x, a, b; - rtx jump, cond, cond_earliest; - /* True if "b" was originally evaluated unconditionally. */ - bool b_unconditional; + + /* The SET_SRC of INSN_A and INSN_B. */ + rtx a, b; + + /* The SET_DEST of INSN_A. */ + rtx x; }; static rtx noce_emit_store_flag (struct noce_if_info *, rtx, int, int); @@ -1877,9 +1896,10 @@ noce_try_sign_mask (struct noce_if_info *if_info) return FALSE; /* This is only profitable if T is cheap, or T is unconditionally - executed/evaluated in the original insn sequence. */ + executed/evaluated in the original insn sequence. The latter + happens if INSN_B was taken from TEST_BB. */ if (rtx_cost (t, SET) >= COSTS_N_INSNS (2) - && (!if_info->b_unconditional + && (BLOCK_FOR_INSN (if_info->insn_b) != if_info->test_bb || t != if_info->b)) return FALSE; @@ -2173,6 +2193,7 @@ noce_process_if_block (struct ce_if_block * ce_info) basic_block test_bb = ce_info->test_bb; /* test block */ basic_block then_bb = ce_info->then_bb; /* THEN */ basic_block else_bb = ce_info->else_bb; /* ELSE or NULL */ + basic_block join_bb; struct noce_if_info if_info; rtx insn_a, insn_b; rtx set_a, set_b; @@ -2283,7 +2304,6 @@ noce_process_if_block (struct ce_if_block * ce_info) if_info.x = x; if_info.a = a; if_info.b = b; - if_info.b_unconditional = else_bb == 0; /* Try optimizations in some approximation of a useful order. */ /* ??? Should first look to see if X is live incoming at all. If it @@ -2364,39 +2384,47 @@ noce_process_if_block (struct ce_if_block * ce_info) return FALSE; success: - /* The original sets may now be killed. */ - delete_insn (insn_a); - - /* Several special cases here: First, we may have reused insn_b above, - in which case insn_b is now NULL. Second, we want to delete insn_b - if it came from the ELSE block, because follows the now correct - write that appears in the TEST block. However, if we got insn_b from - the TEST block, it may in fact be loading data needed for the comparison. - We'll let life_analysis remove the insn if it's really dead. */ - if (insn_b && else_bb) - delete_insn (insn_b); - - /* The new insns will have been inserted immediately before the jump. We - should be able to remove the jump with impunity, but the condition itself - may have been modified by gcse to be shared across basic blocks. */ - delete_insn (jump); /* If we used a temporary, fix it up now. */ if (orig_x != x) { + rtx seq; + start_sequence (); noce_emit_move_insn (orig_x, x); - insn_b = get_insns (); + seq = get_insns (); set_used_flags (orig_x); - unshare_all_rtl_in_chain (insn_b); + unshare_all_rtl_in_chain (seq); end_sequence (); - emit_insn_after_setloc (insn_b, BB_END (test_bb), INSN_LOCATOR (insn_a)); + emit_insn_before_setloc (seq, BB_END (test_bb), INSN_LOCATOR (insn_a)); } - /* Merge the blocks! */ - merge_if_block (ce_info); + /* The original THEN and ELSE blocks may now be removed. The test block + must now jump to the join block. If the test block and the join block + can be merged, do so. */ + join_bb = single_succ (then_bb); + if (else_bb) + { + delete_basic_block (else_bb); + num_true_changes++; + } + else + remove_edge (find_edge (test_bb, join_bb)); + + remove_edge (find_edge (then_bb, join_bb)); + redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb); + delete_basic_block (then_bb); + num_true_changes++; + + if (can_merge_blocks_p (test_bb, join_bb)) + { + merge_blocks (test_bb, join_bb); + num_true_changes++; + } + + num_updated_if_blocks++; return TRUE; } @@ -2463,6 +2491,12 @@ check_cond_move_block (basic_block bb, rtx *vals, rtx cond) return FALSE; } + /* We can only handle simple jumps at the end of the basic block. + It is almost impossible to update the CFG otherwise. */ + insn = BB_END (bb); + if (JUMP_P (insn) && ! onlyjump_p (insn)) + return FALSE; + return TRUE; } @@ -2537,10 +2571,12 @@ cond_move_convert_if_block (struct noce_if_info *if_infop, static int cond_move_process_if_block (struct ce_if_block *ce_info) { + basic_block test_bb = ce_info->test_bb; basic_block then_bb = ce_info->then_bb; basic_block else_bb = ce_info->else_bb; + basic_block join_bb; struct noce_if_info if_info; - rtx jump, cond, insn, seq, loc_insn; + rtx jump, cond, seq, loc_insn; int max_reg, size, c, i; rtx *then_vals; rtx *else_vals; @@ -2624,21 +2660,30 @@ cond_move_process_if_block (struct ce_if_block *ce_info) } emit_insn_before_setloc (seq, jump, INSN_LOCATOR (loc_insn)); - FOR_BB_INSNS (then_bb, insn) - if (INSN_P (insn) && !JUMP_P (insn)) - delete_insn (insn); + join_bb = single_succ (then_bb); if (else_bb) { - FOR_BB_INSNS (else_bb, insn) - if (INSN_P (insn) && !JUMP_P (insn)) - delete_insn (insn); + delete_basic_block (else_bb); + num_true_changes++; } - delete_insn (jump); + else + remove_edge (find_edge (test_bb, join_bb)); - merge_if_block (ce_info); + remove_edge (find_edge (then_bb, join_bb)); + redirect_edge_and_branch_force (single_succ_edge (test_bb), join_bb); + delete_basic_block (then_bb); + num_true_changes++; + + if (can_merge_blocks_p (test_bb, join_bb)) + { + merge_blocks (test_bb, join_bb); + num_true_changes++; + } + num_updated_if_blocks++; return TRUE; } + /* Attempt to convert an IF-THEN or IF-THEN-ELSE block into straight line code. Return true if successful. */ @@ -3201,29 +3246,20 @@ find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge) if (seq == NULL) return FALSE; - num_true_changes++; - /* Emit the new insns before cond_earliest. */ emit_insn_before_setloc (seq, cond_earliest, INSN_LOCATOR (trap)); /* Delete the trap block if possible. */ remove_edge (trap_bb == then_bb ? then_edge : else_edge); if (EDGE_COUNT (trap_bb->preds) == 0) - delete_basic_block (trap_bb); - - /* If the non-trap block and the test are now adjacent, merge them. - Otherwise we must insert a direct branch. */ - if (test_bb->next_bb == other_bb) { - struct ce_if_block new_ce_info; - delete_insn (jump); - memset (&new_ce_info, '\0', sizeof (new_ce_info)); - new_ce_info.test_bb = test_bb; - new_ce_info.then_bb = NULL; - new_ce_info.else_bb = NULL; - new_ce_info.join_bb = other_bb; - merge_if_block (&new_ce_info); + delete_basic_block (trap_bb); + num_true_changes++; } + + /* Wire together the blocks again. */ + if (current_ir_type () == IR_RTL_CFGLAYOUT) + single_succ_edge (test_bb)->flags |= EDGE_FALLTHRU; else { rtx lab, newjump; @@ -3233,10 +3269,16 @@ find_cond_trap (basic_block test_bb, edge then_edge, edge else_edge) LABEL_NUSES (lab) += 1; JUMP_LABEL (newjump) = lab; emit_barrier_after (newjump); + } + delete_insn (jump); - delete_insn (jump); + if (can_merge_blocks_p (test_bb, other_bb)) + { + merge_blocks (test_bb, other_bb); + num_true_changes++; } + num_updated_if_blocks++; return TRUE; }