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* Improved register allocator and fixed bug where a call to "is_same_reg_move" would leave behind dangling pointers

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This commit is contained in:
J. Gareth "Curious Kit" Moreton 2025-06-22 21:49:00 +01:00 committed by FPK
parent 6e0b67d5f7
commit 7a4dbdc5aa
1 changed files with 36 additions and 6 deletions
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42
compiler/rgobj.pas
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@ -1954,9 +1954,14 @@ unit rgobj;
p:=live_end;
while assigned(p) and
assigned(p.previous) and
(tai(p.previous).typ=ait_regalloc) and
(tai_regalloc(p.previous).ratype=ra_alloc) and
(tai_regalloc(p.previous).reg<>r) do
(
(tai(p.previous).typ in [ait_comment,ait_tempalloc,ait_varloc]) or
(
(tai(p.previous).typ=ait_regalloc) and
(tai_regalloc(p.previous).ratype=ra_alloc) and
(tai_regalloc(p.previous).reg<>r)
)
) do
p:=tai(p.previous);
{ , but add release after a reg_a_sync }
if assigned(p) and
@ -2395,6 +2400,23 @@ unit rgobj;
it is a move and both arguments are the same }
if is_same_reg_move(regtype) then
begin
{ Be careful of dangling pointers in previous reg_allocs,
ss these can confuse the register allocator }
hp:=tai(p.previous);
while Assigned(hp) do
begin
if (hp.typ in [ait_comment,ait_varloc]) then
{ Do nothing, but pass control flow to
"hp:=tai(hp.previous)" and continue the loop }
else if (hp.typ=ait_regalloc) then
begin
if tai_regalloc(hp).instr=p then
tai_regalloc(hp).instr:=nil;
end
else
Break;
hp:=tai(hp.previous);
end;
remove_ai(list,p);
continue;
end;
@ -2877,13 +2899,21 @@ unit rgobj;
they can't be used during the spilling }
loadpos:=tai(instr.previous);
while assigned(loadpos) and
(
(loadpos.typ in [ait_comment,ait_tempalloc,ait_varloc]) or
(
(loadpos.typ=ait_regalloc) and
((tai_regalloc(loadpos).instr=nil) or
(tai_regalloc(loadpos).instr=instr)) do
(
(tai_regalloc(loadpos).instr=nil) or
(tai_regalloc(loadpos).instr=instr)
)
)
) do
begin
{ Only add deallocs belonging to the instruction. Explicit inserted deallocs
belong to the previous instruction and not the current instruction }
if (tai_regalloc(loadpos).instr=instr) and
if (loadpos.typ=ait_regalloc) and
(tai_regalloc(loadpos).instr=instr) and
(tai_regalloc(loadpos).ratype=ra_dealloc) then
live_registers.add(get_alias(getsupreg(tai_regalloc(loadpos).reg)));
loadpos:=tai(loadpos.previous);