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+ MovSubCmp2MovSub optimization

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This commit is contained in:
florian 2022-10-30 16:57:59 +01:00
parent ae12a79bf7
commit a1064ad8fd
1 changed files with 26 additions and 2 deletions
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28
compiler/x86/aoptx86.pas
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@ -2819,8 +2819,8 @@ unit aoptx86;
if taicpu(p).oper[1]^.typ = top_reg then
begin
{ Saves on a large number of dereferences }
p_TargetReg := taicpu(p).oper[1]^.reg;
{ Saves on a large number of dereferences }
p_TargetReg := taicpu(p).oper[1]^.reg;
{ Look for:
mov %reg1,%reg2
@ -4613,6 +4613,30 @@ unit aoptx86;
exit;
end;
if MatchInstruction(hp1,A_SUB,[Taicpu(p).opsize]) and
MatchOperand(Taicpu(p).oper[1]^,Taicpu(hp1).oper[1]^) and
GetNextInstruction(hp1, hp2) and
MatchInstruction(hp2,A_CMP,[Taicpu(p).opsize]) and
MatchOperand(Taicpu(p).oper[0]^,Taicpu(hp2).oper[1]^) and
MatchOperand(Taicpu(hp1).oper[0]^,Taicpu(hp2).oper[0]^) then
{ change
mov reg1,reg2
sub reg3,reg2
cmp reg3,reg1
into
mov reg1,reg2
sub reg3,reg2
}
begin
DebugMsg(SPeepholeOptimization + 'MovSubCmp2MovSub done',p);
RemoveInstruction(hp2);
Result:=true;
exit;
end;
{
mov ref,reg0
<op> reg0,reg1