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* tcg386.g_copyvaluepara_openarray, improved generated code:

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- second calculation of EDI is obsolete, its value is never used.
  - calculation of ECX can be partially shared with first calculation of EDI.
  - multiplying ECX by 1 is also redundant (was happening due to a wrong condition).

git-svn-id: trunk@17260 -
This commit is contained in:
sergei 2011-04-06 08:54:20 +00:00
parent c17afffb65
commit c6accaba5c
1 changed files with 10 additions and 28 deletions
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38
compiler/i386/cgcpu.pas
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@ -371,6 +371,9 @@ unit cgcpu;
getcpuregister(list,NR_EDI);
a_load_loc_reg(list,OS_INT,lenloc,NR_EDI);
list.concat(Taicpu.op_reg(A_INC,S_L,NR_EDI));
{ Now EDI contains (high+1). Copy it to ECX for later use. }
getcpuregister(list,NR_ECX);
list.concat(Taicpu.op_reg_reg(A_MOV,S_L,NR_EDI,NR_ECX));
if (elesize<>1) then
begin
if ispowerof2(elesize, power) then
@ -394,43 +397,22 @@ unit cgcpu;
a_jmp_always(list,again);
a_label(list,ok);
list.concat(Taicpu.op_reg_reg(A_SUB,S_L,NR_EDI,NR_ESP));
ungetcpuregister(list,NR_EDI);
{ now reload EDI }
getcpuregister(list,NR_EDI);
a_load_loc_reg(list,OS_INT,lenloc,NR_EDI);
list.concat(Taicpu.op_reg(A_INC,S_L,NR_EDI));
if (elesize<>1) then
begin
if ispowerof2(elesize, power) then
list.concat(Taicpu.op_const_reg(A_SHL,S_L,power,NR_EDI))
else
list.concat(Taicpu.op_const_reg(A_IMUL,S_L,elesize,NR_EDI));
end;
end
else
end;
{$endif __NOWINPECOFF__}
list.concat(Taicpu.op_reg_reg(A_SUB,S_L,NR_EDI,NR_ESP));
{ If we were probing pages, EDI=(size mod pagesize) and ESP is decremented
by (size div pagesize)*pagesize, otherwise EDI=size.
Either way, subtracting EDI from ESP will set ESP to desired final value. }
list.concat(Taicpu.op_reg_reg(A_SUB,S_L,NR_EDI,NR_ESP));
{ align stack on 4 bytes }
list.concat(Taicpu.op_const_reg(A_AND,S_L,aint($fffffff4),NR_ESP));
{ load destination, don't use a_load_reg_reg, that will add a move instruction
that can confuse the reg allocator }
list.concat(Taicpu.Op_reg_reg(A_MOV,S_L,NR_ESP,NR_EDI));
{ Allocate other registers }
getcpuregister(list,NR_ECX);
{ Allocate ESI and load it with source }
getcpuregister(list,NR_ESI);
{ load count }
a_load_loc_reg(list,OS_INT,lenloc,NR_ECX);
{ load source }
a_loadaddr_ref_reg(list,ref,NR_ESI);
{ scheduled .... }
list.concat(Taicpu.op_reg(A_INC,S_L,NR_ECX));
{ calculate size }
len:=elesize;
opsize:=S_B;
@ -446,7 +428,7 @@ unit cgcpu;
len:=len shr 1;
end;
if len<>0 then
if len>1 then
begin
if ispowerof2(len, power) then
list.concat(Taicpu.op_const_reg(A_SHL,S_L,power,NR_ECX))