diff options
| -rw-r--r-- | lib/hipe/x86/hipe_x86_postpass.erl | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/lib/hipe/x86/hipe_x86_postpass.erl b/lib/hipe/x86/hipe_x86_postpass.erl index 4515822a34..bd232041b6 100644 --- a/lib/hipe/x86/hipe_x86_postpass.erl +++ b/lib/hipe/x86/hipe_x86_postpass.erl @@ -120,19 +120,15 @@ peep([#move{src=Src1, dst=Dst}, %% ElimCmp0 %% -------- -peep([C=#cmp{src=Src, dst=Dst},J=#jcc{cc=Cond, label=Lab}|Insns],Res,Lst) -> - case (((Src =:= #x86_imm{value=0}) or (Dst =:= #x86_imm{value=0})) and - ((Cond =:= 'eq') or (Cond =:= 'neq'))) of - true -> - Src2 = case Src of #x86_imm{value=0} -> Src; _ -> Dst end, - Cond2 = case Cond of 'eq' -> 'z'; 'neq' -> 'nz' end, - Test = #test{src=Src2, dst=#x86_imm{value=0}}, - Jump = #jcc{cc=Cond2, label=Lab}, - peep(Insns, [Jump, Test|Res], [elimCmp0|Lst]); - _ -> - peep(Insns, [J,C|Res], Lst) - end; - +peep([#cmp{src=#x86_imm{value=0}, dst=Dst=#x86_temp{}}|Insns],Res,Lst) -> + %% TEST leaves the adjust flag undefined, whereas CMP sets it properly (in + %% this case to 0). However, since HiPE does not use any instructions that + %% read the adjust flag, we can do this transform safely. + peep(Insns, [#test{src=Dst, dst=Dst} | Res], [elimCmp0_1|Lst]); +peep([#cmp{src=Src=#x86_temp{}, dst=#x86_imm{value=0}}, + J=#jcc{cc=Cond}|Insns],Res,Lst) + when Cond =:= 'e'; Cond =:= 'ne' -> % We're commuting the comparison + peep(Insns, [J, #test{src=Src, dst=Src} | Res], [elimCmp0_2|Lst]); %% ElimCmpTest %% ----------- |