diff options
Diffstat (limited to 'gcc/ifcvt.c')
| -rw-r--r-- | gcc/ifcvt.c | 134 |
1 files changed, 131 insertions, 3 deletions
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index 6cb2fab..6196522 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -48,6 +48,12 @@ #ifndef HAVE_decscc #define HAVE_decscc 0 #endif +#ifndef HAVE_trap +#define HAVE_trap 0 +#endif +#ifndef HAVE_conditional_trap +#define HAVE_conditional_trap 0 +#endif #ifndef MAX_CONDITIONAL_EXECUTE #define MAX_CONDITIONAL_EXECUTE (BRANCH_COST + 1) @@ -97,6 +103,7 @@ static int find_if_header PARAMS ((basic_block)); static int find_if_block PARAMS ((basic_block, edge, edge)); static int find_if_case_1 PARAMS ((basic_block, edge, edge)); static int find_if_case_2 PARAMS ((basic_block, edge, edge)); +static int find_cond_trap PARAMS ((basic_block, edge, edge)); static int find_memory PARAMS ((rtx *, void *)); static int dead_or_predicable PARAMS ((basic_block, basic_block, basic_block, rtx, int)); @@ -1757,10 +1764,9 @@ merge_if_block (test_bb, then_bb, else_bb, join_bb) if (combo_bb->succ == NULL_EDGE) abort (); - /* There should sill be a branch at the end of the THEN or ELSE + /* There should still be a branch at the end of the THEN or ELSE blocks taking us to our final destination. */ - if (! any_uncondjump_p (combo_bb->end) - && ! returnjump_p (combo_bb->end)) + if (GET_CODE (combo_bb->end) != JUMP_INSN) abort (); } @@ -1835,6 +1841,9 @@ find_if_header (test_bb) if (find_if_block (test_bb, then_edge, else_edge)) goto success; + if (HAVE_trap && HAVE_conditional_trap + && find_cond_trap (test_bb, then_edge, else_edge)) + goto success; if (post_dominators && (! HAVE_conditional_execution || reload_completed)) { @@ -1965,6 +1974,125 @@ find_if_block (test_bb, then_edge, else_edge) return process_if_block (test_bb, then_bb, else_bb, join_bb); } +/* Convert a branch over a trap, or a branch to a trap, + into a conditional trap. */ + +static int +find_cond_trap (test_bb, then_edge, else_edge) + basic_block test_bb; + edge then_edge, else_edge; +{ + basic_block then_bb, else_bb, join_bb, trap_bb; + rtx trap, jump, cond, cond_earliest, seq; + enum rtx_code code; + + then_bb = then_edge->dest; + else_bb = else_edge->dest; + join_bb = NULL; + + /* Locate the block with the trap instruction. */ + /* ??? While we look for no successors, we really ought to allow + EH successors. Need to fix merge_if_block for that to work. */ + /* ??? We can't currently handle merging the blocks if they are not + already adjacent. Prevent losage in merge_if_block by detecting + this now. */ + if (then_bb->succ == NULL) + { + trap_bb = then_bb; + if (else_bb->index != then_bb->index + 1) + return FALSE; + join_bb = else_bb; + else_bb = NULL; + } + else if (else_bb->succ == NULL) + { + trap_bb = else_bb; + if (else_bb->index != then_bb->index + 1) + else_bb = NULL; + else if (then_bb->succ + && ! then_bb->succ->succ_next + && ! (then_bb->succ->flags & EDGE_COMPLEX) + && then_bb->succ->dest->index == else_bb->index + 1) + join_bb = then_bb->succ->dest; + } + else + return FALSE; + + /* The only instruction in the THEN block must be the trap. */ + trap = first_active_insn (trap_bb); + if (! (trap == trap_bb->end + && GET_CODE (PATTERN (trap)) == TRAP_IF + && TRAP_CONDITION (PATTERN (trap)) == const_true_rtx)) + return FALSE; + + if (rtl_dump_file) + { + if (trap_bb == then_bb) + fprintf (rtl_dump_file, + "\nTRAP-IF block found, start %d, trap %d", + test_bb->index, then_bb->index); + else + fprintf (rtl_dump_file, + "\nTRAP-IF block found, start %d, then %d, trap %d", + test_bb->index, then_bb->index, trap_bb->index); + if (join_bb) + fprintf (rtl_dump_file, ", join %d\n", join_bb->index); + else + fputc ('\n', rtl_dump_file); + } + + /* If this is not a standard conditional jump, we can't parse it. */ + jump = test_bb->end; + cond = noce_get_condition (jump, &cond_earliest); + if (! cond) + return FALSE; + + /* If the conditional jump is more than just a conditional jump, + then we can not do if-conversion on this block. */ + if (! onlyjump_p (jump)) + return FALSE; + + /* We must be comparing objects whose modes imply the size. */ + if (GET_MODE (XEXP (cond, 0)) == BLKmode) + return FALSE; + + /* Reverse the comparison code, if necessary. */ + code = GET_CODE (cond); + if (then_bb == trap_bb) + { + code = reversed_comparison_code (cond, jump); + if (code == UNKNOWN) + return FALSE; + } + + /* Attempt to generate the conditional trap. */ + seq = gen_cond_trap (code, XEXP (cond, 0), XEXP (cond, 1), + TRAP_CODE (PATTERN (trap))); + if (seq == NULL) + return FALSE; + + /* Emit the new insns before cond_earliest; delete the old jump + and trap insns. */ + + emit_insn_before (seq, cond_earliest); + + test_bb->end = PREV_INSN (jump); + flow_delete_insn (jump); + + trap_bb->end = PREV_INSN (trap); + flow_delete_insn (trap); + + /* Merge the blocks! */ + if (trap_bb != then_bb && ! else_bb) + { + flow_delete_block (trap_bb); + num_removed_blocks++; + } + merge_if_block (test_bb, then_bb, else_bb, join_bb); + + return TRUE; +} + /* Look for IF-THEN-ELSE cases in which one of THEN or ELSE is transformable, but not necessarily the other. There need be no JOIN block. |