diff options
Diffstat (limited to 'lib/compiler/src/beam_bool.erl')
| -rw-r--r-- | lib/compiler/src/beam_bool.erl | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/lib/compiler/src/beam_bool.erl b/lib/compiler/src/beam_bool.erl index ffe5cdb501..dcc6ad4c7c 100644 --- a/lib/compiler/src/beam_bool.erl +++ b/lib/compiler/src/beam_bool.erl @@ -173,7 +173,7 @@ bopt_block(Reg, Fail, OldIs, [{block,Bl0}|Acc0], St0) -> %% whether the optimized code is guaranteed to work in the same %% way as the original code. %% -%% Throws an exception if the optmization is not safe. +%% Throw an exception if the optimization is not safe. %% ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) -> %% Here are the conditions that must be true for the @@ -190,10 +190,10 @@ ensure_opt_safe(Bl, NewCode, OldIs, Fail, PreceedingCode, St) -> %% by the code that follows. %% %% 3. Any register that is assigned a value in the optimized - %% code must be UNUSED or KILLED in the following code. - %% (Possible future improvement: Registers that are known - %% to be assigned the SAME value in the original and optimized - %% code don't need to be unused in the following code.) + %% code must be UNUSED or KILLED in the following code + %% (because the register might be assigned the wrong value, + %% and even if the value is right it might no longer be + %% assigned on *all* paths leading to its use). InitInPreceeding = initialized_regs(PreceedingCode), @@ -310,6 +310,8 @@ dst_regs([{set,[D],_,{bif,_,{f,_}}}|Is], Acc) -> dst_regs(Is, [D|Acc]); dst_regs([{set,[D],_,{alloc,_,{gc_bif,_,{f,_}}}}|Is], Acc) -> dst_regs(Is, [D|Acc]); +dst_regs([{set,[D],_,move}|Is], Acc) -> + dst_regs(Is, [D|Acc]); dst_regs([_|Is], Acc) -> dst_regs(Is, Acc); dst_regs([], Acc) -> ordsets:from_list(Acc). |