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* make use of xor reg,reg by generating it directly instead of hoping for the peephole

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optimizer which cannot do this properly due to missing information about flags. By doing
  so the size of the compiler executable gets reduced by ~1 %

git-svn-id: trunk@33524 -
This commit is contained in:
florian 2016-04-15 19:27:22 +00:00
parent 2dbcdbe466
commit f576b0c01b
2 changed files with 4 additions and 13 deletions
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10
compiler/i386/popt386.pas
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@ -453,16 +453,6 @@ begin
hp1.free;
end;
end;
A_XOR:
if (taicpu(p).oper[0]^.typ = top_reg) and
(taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(p).oper[0]^.reg = taicpu(p).oper[1]^.reg) then
{ temporarily change this to 'mov reg,0' to make it easier }
{ for the CSE. Will be changed back in pass 2 }
begin
taicpu(p).opcode := A_MOV;
taicpu(p).loadConst(0,0);
end;
end;
end;
end;

7
compiler/x86/cgx86.pas
View File

@ -909,9 +909,10 @@ unit cgx86;
begin
check_register_size(tosize,reg);
{ the optimizer will change it to "xor reg,reg" when loading zero, }
{ no need to do it here too (JM) }
list.concat(taicpu.op_const_reg(A_MOV,TCGSize2OpSize[tosize],a,reg))
if a=0 then
list.concat(taicpu.op_reg_reg(A_XOR,TCGSize2OpSize[tosize],reg,reg))
else
list.concat(taicpu.op_const_reg(A_MOV,TCGSize2OpSize[tosize],a,reg));
end;