diff options
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 21 |
1 files changed, 18 insertions, 3 deletions
@@ -637,6 +637,7 @@ update_life_info (blocks, extent, prop_flags) regset tmp; regset_head tmp_head; int i; + int stabilized_prop_flags = prop_flags; tmp = INITIALIZE_REG_SET (tmp_head); ndead = 0; @@ -677,8 +678,21 @@ update_life_info (blocks, extent, prop_flags) | PROP_KILL_DEAD_CODE)); } - if (! changed || ! cleanup_cfg (CLEANUP_EXPENSIVE)) + /* Don't pass PROP_SCAN_DEAD_CODE or PROP_KILL_DEAD_CODE to + subsequent propagate_block calls, since removing or acting as + removing dead code can affect global register liveness, which + is supposed to be finalized for this call after this loop. */ + stabilized_prop_flags + &= ~(PROP_SCAN_DEAD_CODE | PROP_KILL_DEAD_CODE); + + if (! changed) break; + + /* We repeat regardless of what cleanup_cfg says. If there were + instructions deleted above, that might have been only a + partial improvement (see MAX_MEM_SET_LIST_LEN usage). + Further improvement may be possible. */ + cleanup_cfg (CLEANUP_EXPENSIVE); } /* If asked, remove notes from the blocks we'll update. */ @@ -697,7 +711,7 @@ update_life_info (blocks, extent, prop_flags) basic_block bb = BASIC_BLOCK (i); COPY_REG_SET (tmp, bb->global_live_at_end); - propagate_block (bb, tmp, NULL, NULL, prop_flags); + propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags); if (extent == UPDATE_LIFE_LOCAL) verify_local_live_at_start (tmp, bb); @@ -710,7 +724,8 @@ update_life_info (blocks, extent, prop_flags) basic_block bb = BASIC_BLOCK (i); COPY_REG_SET (tmp, bb->global_live_at_end); - propagate_block (bb, tmp, NULL, NULL, prop_flags); + + propagate_block (bb, tmp, NULL, NULL, stabilized_prop_flags); if (extent == UPDATE_LIFE_LOCAL) verify_local_live_at_start (tmp, bb); |