diff options
Diffstat (limited to 'gcc/cfglayout.c')
| -rw-r--r-- | gcc/cfglayout.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/gcc/cfglayout.c b/gcc/cfglayout.c index 899aa1a5665..66742686e16 100644 --- a/gcc/cfglayout.c +++ b/gcc/cfglayout.c @@ -714,6 +714,10 @@ fixup_reorder_chain (void) && invert_jump (bb_end_insn, label_for_bb (e_fall->dest), 0)) { +#ifdef ENABLE_CHECKING + if (!could_fall_through (e_taken->src, e_taken->dest)) + abort (); +#endif e_fall->flags &= ~EDGE_FALLTHRU; e_taken->flags |= EDGE_FALLTHRU; update_br_prob_note (bb); @@ -731,6 +735,10 @@ fixup_reorder_chain (void) else if (invert_jump (bb_end_insn, label_for_bb (e_fall->dest), 0)) { +#ifdef ENABLE_CHECKING + if (!could_fall_through (e_taken->src, e_taken->dest)) + abort (); +#endif e_fall->flags &= ~EDGE_FALLTHRU; e_taken->flags |= EDGE_FALLTHRU; update_br_prob_note (bb); @@ -770,7 +778,7 @@ fixup_reorder_chain (void) continue; /* A fallthru to exit block. */ - if (!bb->rbi->next && e_fall->dest == EXIT_BLOCK_PTR) + if (e_fall->dest == EXIT_BLOCK_PTR) continue; } @@ -910,14 +918,20 @@ verify_insn_chain (void) abort (); } -/* The block falling through to exit must be the last one in the - reordered chain. Ensure that this condition is met. */ +/* If we have assembler epilogues, the block falling through to exit must + be the last one in the reordered chain when we reach final. Ensure + that this condition is met. */ static void fixup_fallthru_exit_predecessor (void) { edge e; basic_block bb = NULL; + /* This transformation is not valid before reload, because we might separate + a call from the instruction that copies the return value. */ + if (! reload_completed) + abort (); + for (e = EXIT_BLOCK_PTR->pred; e; e = e->pred_next) if (e->flags & EDGE_FALLTHRU) bb = e->src; @@ -926,6 +940,18 @@ fixup_fallthru_exit_predecessor (void) { basic_block c = ENTRY_BLOCK_PTR->next_bb; + /* If the very first block is the one with the fall-through exit + edge, we have to split that block. */ + if (c == bb) + { + bb = split_block (bb, NULL)->dest; + initialize_bb_rbi (bb); + bb->rbi->next = c->rbi->next; + c->rbi->next = bb; + bb->rbi->footer = c->rbi->footer; + c->rbi->footer = NULL; + } + while (c->rbi->next != bb) c = c->rbi->next; @@ -1176,7 +1202,12 @@ cfg_layout_finalize (void) verify_flow_info (); #endif rtl_register_cfg_hooks (); - fixup_fallthru_exit_predecessor (); + if (reload_completed +#ifdef HAVE_epilogue + && !HAVE_epilogue +#endif + ) + fixup_fallthru_exit_predecessor (); fixup_reorder_chain (); #ifdef ENABLE_CHECKING |