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Look ahead more than one instruction in FoldShiftProcess for ARM

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Up until now we only checked the next instruction, with the new load
scheduler this is insufficient as shift-instructions and next usage
might farther apart.

The new version uses GetNextInstructionUsingReg, this also comes with a
price as we very carefully have to check if one of the used registers is
changed and that the usage of RRX will not break when we fold and flags
get changed in between.

git-svn-id: trunk@22876 -
This commit is contained in:
masta 2012-10-29 17:57:11 +00:00
parent 7106b4dd54
commit 3a017f76d0
1 changed files with 63 additions and 46 deletions
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109
compiler/arm/aoptcpu.pas
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@ -956,72 +956,89 @@ Implementation
(taicpu(p).oper[1]^.typ = top_reg) and
(taicpu(p).oper[2]^.typ = top_shifterop) and
(taicpu(p).oppostfix = PF_NONE) and
GetNextInstruction(p, hp1) and
GetNextInstructionUsingReg(p, hp1, taicpu(p).oper[0]^.reg) and
MatchInstruction(hp1, [A_ADD, A_ADC, A_RSB, A_RSC, A_SUB, A_SBC,
A_AND, A_BIC, A_EOR, A_ORR, A_TEQ, A_TST,
A_CMP, A_CMN],
[taicpu(p).condition], [PF_None]) and
(taicpu(hp1).ops >= 2) and {Currently we can't fold into another shifterop}
(assigned(FindRegDealloc(taicpu(p).oper[0]^.reg,tai(hp1.Next))) or
regLoadedWithNewValue(taicpu(p).oper[0]^.reg, hp1)) and
(taicpu(hp1).ops >= 2) and
{Currently we can't fold into another shifterop}
(taicpu(hp1).oper[taicpu(hp1).ops-1]^.typ = top_reg) and
{Folding rrx is problematic because of the C-Flag, as we currently can't check
NR_DEFAULTFLAGS for modification}
(
{Everything is fine if we don't use RRX}
(taicpu(p).oper[2]^.shifterop^.shiftmode <> SM_RRX) or
(
{If it is RRX, then check if we're just accessing the next instruction}
GetNextInstruction(p, hp2) and
(hp1 = hp2)
)
) and
{ reg1 might not be modified inbetween }
not(RegModifiedBetween(taicpu(p).oper[1]^.reg,p,hp1)) and
{ The shifterop can contain a register, might not be modified}
(
(taicpu(p).oper[2]^.shifterop^.rs = NR_NO) or
not(RegModifiedBetween(taicpu(p).oper[2]^.shifterop^.rs, p, hp1))
) and
(
{Only ONE of the two src operands is allowed to match}
MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[taicpu(hp1).ops-2]^) xor
MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[taicpu(hp1).ops-1]^)
) then
begin
CopyUsedRegs(TmpUsedRegs);
UpdateUsedRegs(TmpUsedRegs, tai(p.next));
if taicpu(hp1).opcode in [A_TST, A_TEQ, A_CMN] then
I2:=0
else
I2:=1;
if not(RegUsedAfterInstruction(taicpu(p).oper[0]^.reg,hp1,TmpUsedRegs)) then
for I:=I2 to taicpu(hp1).ops-1 do
if MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[I]^.reg) then
begin
{ If the parameter matched on the second op from the RIGHT
we have to switch the parameters, this will not happen for CMP
were we're only evaluating the most right parameter
}
if I <> taicpu(hp1).ops-1 then
begin
{The SUB operators need to be changed when we swap parameters}
case taicpu(hp1).opcode of
A_SUB: tempop:=A_RSB;
A_SBC: tempop:=A_RSC;
A_RSB: tempop:=A_SUB;
A_RSC: tempop:=A_SBC;
else tempop:=taicpu(hp1).opcode;
end;
if taicpu(hp1).ops = 3 then
hp2:=taicpu.op_reg_reg_reg_shifterop(tempop,
taicpu(hp1).oper[0]^.reg, taicpu(hp1).oper[2]^.reg,
taicpu(p).oper[1]^.reg, taicpu(p).oper[2]^.shifterop^)
else
hp2:=taicpu.op_reg_reg_shifterop(tempop,
taicpu(hp1).oper[0]^.reg, taicpu(p).oper[1]^.reg,
taicpu(p).oper[2]^.shifterop^);
end
else
for I:=I2 to taicpu(hp1).ops-1 do
if MatchOperand(taicpu(p).oper[0]^, taicpu(hp1).oper[I]^.reg) then
begin
{ If the parameter matched on the second op from the RIGHT
we have to switch the parameters, this will not happen for CMP
were we're only evaluating the most right parameter
}
if I <> taicpu(hp1).ops-1 then
begin
{The SUB operators need to be changed when we swap parameters}
case taicpu(hp1).opcode of
A_SUB: tempop:=A_RSB;
A_SBC: tempop:=A_RSC;
A_RSB: tempop:=A_SUB;
A_RSC: tempop:=A_SBC;
else tempop:=taicpu(hp1).opcode;
end;
if taicpu(hp1).ops = 3 then
hp2:=taicpu.op_reg_reg_reg_shifterop(taicpu(hp1).opcode,
taicpu(hp1).oper[0]^.reg, taicpu(hp1).oper[1]^.reg,
hp2:=taicpu.op_reg_reg_reg_shifterop(tempop,
taicpu(hp1).oper[0]^.reg, taicpu(hp1).oper[2]^.reg,
taicpu(p).oper[1]^.reg, taicpu(p).oper[2]^.shifterop^)
else
hp2:=taicpu.op_reg_reg_shifterop(taicpu(hp1).opcode,
hp2:=taicpu.op_reg_reg_shifterop(tempop,
taicpu(hp1).oper[0]^.reg, taicpu(p).oper[1]^.reg,
taicpu(p).oper[2]^.shifterop^);
asml.insertbefore(hp2, p);
asml.remove(p);
asml.remove(hp1);
p.free;
hp1.free;
p:=hp2;
GetNextInstruction(p,hp1);
DebugMsg('Peephole FoldShiftProcess done', p);
break;
end;
ReleaseUsedRegs(TmpUsedRegs);
end
else
if taicpu(hp1).ops = 3 then
hp2:=taicpu.op_reg_reg_reg_shifterop(taicpu(hp1).opcode,
taicpu(hp1).oper[0]^.reg, taicpu(hp1).oper[1]^.reg,
taicpu(p).oper[1]^.reg, taicpu(p).oper[2]^.shifterop^)
else
hp2:=taicpu.op_reg_reg_shifterop(taicpu(hp1).opcode,
taicpu(hp1).oper[0]^.reg, taicpu(p).oper[1]^.reg,
taicpu(p).oper[2]^.shifterop^);
asml.insertbefore(hp2, hp1);
asml.remove(p);
asml.remove(hp1);
p.free;
hp1.free;
p:=hp2;
GetNextInstruction(p,hp1);
DebugMsg('Peephole FoldShiftProcess done', p);
break;
end;
end;
{