diff options
Diffstat (limited to 'gcc/toplev.c')
| -rw-r--r-- | gcc/toplev.c | 26 |
1 files changed, 23 insertions, 3 deletions
diff --git a/gcc/toplev.c b/gcc/toplev.c index fde14d1..b13e580 100644 --- a/gcc/toplev.c +++ b/gcc/toplev.c @@ -63,6 +63,7 @@ Boston, MA 02111-1307, USA. */ #include "regs.h" #include "timevar.h" #include "diagnostic.h" +#include "ssa.h" #ifndef ACCUMULATE_OUTGOING_ARGS #define ACCUMULATE_OUTGOING_ARGS 0 @@ -259,6 +260,7 @@ enum dump_file_index DFI_cse, DFI_addressof, DFI_ssa, + DFI_dce, DFI_ussa, DFI_gcse, DFI_loop, @@ -291,7 +293,7 @@ enum dump_file_index Remaining -d letters: " h o q u " - " H K OPQ TUVWXYZ" + " H K OPQ TUVW YZ" */ struct dump_file_info dump_file[DFI_MAX] = @@ -302,6 +304,7 @@ struct dump_file_info dump_file[DFI_MAX] = { "cse", 's', 0, 0, 0 }, { "addressof", 'F', 0, 0, 0 }, { "ssa", 'e', 1, 0, 0 }, + { "dce", 'X', 1, 0, 0 }, { "ussa", 'e', 1, 0, 0 }, /* Yes, duplicate enable switch. */ { "gcse", 'G', 1, 0, 0 }, { "loop", 'L', 1, 0, 0 }, @@ -786,6 +789,9 @@ int flag_gnu_linker = 1; /* Enable SSA. */ int flag_ssa = 0; +/* Enable dead code elimination. */ +int flag_dce = 0; + /* Tag all structures with __attribute__(packed) */ int flag_pack_struct = 0; @@ -1094,6 +1100,8 @@ lang_independent_options f_options[] = "Instrument function entry/exit with profiling calls"}, {"ssa", &flag_ssa, 1, "Enable SSA optimizations" }, + {"dce", &flag_dce, 1, + "Enable dead code elimination" }, {"leading-underscore", &flag_leading_underscore, 1, "External symbols have a leading underscore" }, {"ident", &flag_no_ident, 0, @@ -2976,13 +2984,25 @@ rest_of_compilation (decl) close_dump_file (DFI_ssa, print_rtl_with_bb, insns); timevar_pop (TV_TO_SSA); - /* Currently, there's nothing to do in SSA form. */ - /* The SSA implementation uses basic block numbers in its phi nodes. Thus, changing the control-flow graph or the basic blocks, e.g., calling find_basic_blocks () or cleanup_cfg (), may cause problems. */ + if (flag_dce) + { + /* Remove dead code. */ + + timevar_push (TV_DEAD_CODE_ELIM); + open_dump_file (DFI_dce, decl); + + insns = get_insns (); + eliminate_dead_code(); + + close_dump_file (DFI_dce, print_rtl_with_bb, insns); + timevar_pop (TV_DEAD_CODE_ELIM); + } + /* Convert from SSA form. */ timevar_push (TV_FROM_SSA); |