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+ LeaCallLeaRet2Jmp optimization

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git-svn-id: trunk@43178 -
This commit is contained in:
florian 2019-10-12 21:51:15 +00:00
parent 00c2fd4005
commit 533a113885
1 changed files with 52 additions and 2 deletions
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54
compiler/x86/aoptx86.pas
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@ -23,7 +23,7 @@ unit aoptx86;
{$i fpcdefs.inc}
{ $define DEBUG_AOPTCPU}
{$define DEBUG_AOPTCPU}
interface
@ -2101,7 +2101,7 @@ unit aoptx86;
function TX86AsmOptimizer.OptPass1LEA(var p : tai) : boolean;
var
hp1 : tai;
hp1, hp2, hp3: tai;
l : ASizeInt;
begin
Result:=false;
@ -2223,6 +2223,56 @@ unit aoptx86;
p:=hp1;
result:=true;
end;
{ replace
lea x(stackpointer),stackpointer
call procname
lea -x(stackpointer),stackpointer
ret
by
jmp procname
this should never hurt except when pic is used, not sure
how to handle it then
but do it only on level 4 because it destroys stack back traces
}
if (cs_opt_level4 in current_settings.optimizerswitches) and
not(cs_create_pic in current_settings.moduleswitches) and
(taicpu(p).oper[1]^.reg=NR_STACK_POINTER_REG) and
(taicpu(p).oper[0]^.ref^.base=NR_STACK_POINTER_REG) and
(taicpu(p).oper[0]^.ref^.index=NR_NO) and
(taicpu(p).oper[0]^.ref^.relsymbol=nil) and
(taicpu(p).oper[0]^.ref^.scalefactor in [0,1]) and
(taicpu(p).oper[0]^.ref^.segment=NR_NO) and
(taicpu(p).oper[0]^.ref^.symbol=nil) and
GetNextInstruction(p, hp1) and
MatchInstruction(hp1,A_CALL,[S_NO]) and
GetNextInstruction(hp1, hp2) and
MatchInstruction(hp2,A_LEA,[taicpu(p).opsize]) and
(taicpu(hp2).oper[1]^.reg=NR_STACK_POINTER_REG) and
(taicpu(p).oper[0]^.ref^.base=taicpu(hp2).oper[0]^.ref^.base) and
(taicpu(p).oper[0]^.ref^.index=taicpu(hp2).oper[0]^.ref^.index) and
(taicpu(p).oper[0]^.ref^.offset=-taicpu(hp2).oper[0]^.ref^.offset) and
(taicpu(p).oper[0]^.ref^.relsymbol=taicpu(hp2).oper[0]^.ref^.relsymbol) and
(taicpu(p).oper[0]^.ref^.scalefactor=taicpu(hp2).oper[0]^.ref^.scalefactor) and
(taicpu(p).oper[0]^.ref^.segment=taicpu(hp2).oper[0]^.ref^.segment) and
(taicpu(p).oper[0]^.ref^.symbol=taicpu(hp2).oper[0]^.ref^.symbol) and
GetNextInstruction(hp2, hp3) and
MatchInstruction(hp3,A_RET,[S_NO]) and
(taicpu(hp3).ops=0) then
begin
DebugMsg(SPeepholeOptimization + 'LeaCallLeaRet2Jmp done',p);
taicpu(hp1).opcode:=A_JMP;
taicpu(hp1).is_jmp:=true;
asml.remove(p);
asml.remove(hp2);
asml.remove(hp3);
p.free;
hp2.free;
hp3.free;
p:=hp1;
Result:=true;
end;
end;