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* Fixed the strength reduction optimization for loops containing 'continue'.

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The compiler now cycles properly with -O3 -OoSTRENGTH.
This commit is contained in:
Yuriy Sydorov 2021-09-15 18:07:12 +03:00
parent b8befe3d1f
commit bd4c206472
1 changed files with 72 additions and 17 deletions
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89
compiler/optloop.pas
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@ -256,7 +256,17 @@ unit optloop;
templist : tfplist;
inductionexprs : tfplist;
changedforloop,
containsnestedforloop : boolean;
containsnestedforloop,
docalcatend: boolean;
function checkcontinue(var n:tnode; arg: pointer): foreachnoderesult;
begin
if n.nodetype=continuen then
result:=fen_norecurse_true
else
result:=fen_false;
end;
function is_loop_invariant(loop : tnode;expr : tnode) : boolean;
begin
@ -330,9 +340,20 @@ unit optloop;
end;
end;
procedure CheckCalcAtEnd;
begin
if not assigned(initcode) then
docalcatend:=not(foreachnodestatic(tfornode(arg).t2,@checkcontinue,nil)) and
not(assigned(tfornode(arg).entrylabel));
end;
var
tempnode : ttempcreatenode;
dummy : longint;
nn : tnode;
nt : tnodetype;
begin
result:=fen_false;
case n.nodetype of
@ -346,9 +367,7 @@ unit optloop;
{ plain read of the loop variable? }
not(nf_write in taddnode(n).right.flags) and
not(nf_modify in taddnode(n).right.flags) and
is_loop_invariant(tfornode(arg),taddnode(n).left) and
{ for now, we can handle only constant lower borders }
is_constnode(tfornode(arg).right) then
is_loop_invariant(tfornode(arg),taddnode(n).left) then
taddnode(n).swapleftright;
if (taddnode(n).left.nodetype=loadn) and
@ -356,14 +375,19 @@ unit optloop;
{ plain read of the loop variable? }
not(nf_write in taddnode(n).left.flags) and
not(nf_modify in taddnode(n).left.flags) and
is_loop_invariant(tfornode(arg),taddnode(n).right) and
{ for now, we can handle only constant lower borders }
is_constnode(tfornode(arg).right) then
is_loop_invariant(tfornode(arg),taddnode(n).right) then
begin
changedforloop:=true;
{ did we use the same expression before already? }
if not(findpreviousstrengthreduction) then
begin
{$ifdef DEBUG_OPTSTRENGTH}
writeln('**********************************************************************************');
writeln(parser_current_file, ': Found expression for strength reduction (MUL): ');
printnode(n);
writeln('**********************************************************************************');
{$endif DEBUG_OPTSTRENGTH}
CheckCalcAtEnd;
tempnode:=ctempcreatenode.create(n.resultdef,n.resultdef.size,tt_persistent,
tstoreddef(n.resultdef).is_intregable or tstoreddef(n.resultdef).is_fpuregable);
@ -381,11 +405,23 @@ unit optloop;
ccallparanode.create(ctemprefnode.create(tempnode),ccallparanode.create(taddnode(n).right.getcopy,nil))));
addstatement(initcodestatements,tempnode);
nn:=tfornode(arg).right.getcopy;
{ If the calculation is not performed at the end
it is needed to adjust the starting value }
if not docalcatend then
begin
if lnf_backward in tfornode(arg).loopflags then
nt:=addn
else
nt:=subn;
nn:=caddnode.create_internal(nt,nn,
cordconstnode.create(1,nn.resultdef,false));
end;
addstatement(initcodestatements,cassignmentnode.create(ctemprefnode.create(tempnode),
caddnode.create(muln,tfornode(arg).right.getcopy,
taddnode(n).right.getcopy)
)
);
caddnode.create(muln,nn,
taddnode(n).right.getcopy)
)
);
{ finally replace the node by a temp. ref }
n:=ctemprefnode.create(tempnode);
@ -426,10 +462,11 @@ unit optloop;
begin
{$ifdef DEBUG_OPTSTRENGTH}
writeln('**********************************************************************************');
writeln('Found expression for strength reduction: ');
writeln(parser_current_file,': Found expression for strength reduction (VEC): ');
printnode(n);
writeln('**********************************************************************************');
{$endif DEBUG_OPTSTRENGTH}
CheckCalcAtEnd;
tempnode:=ctempcreatenode.create(voidpointertype,voidpointertype.size,tt_persistent,true);
templist.Add(tempnode);
@ -448,11 +485,22 @@ unit optloop;
cordconstnode.create(tcgvecnode(n).get_mul_size,sizeuinttype,false),nil))));
addstatement(initcodestatements,tempnode);
addstatement(initcodestatements,cassignmentnode.create(ctemprefnode.create(tempnode),
caddrnode.create(
nn:=caddrnode.create(
cvecnode.create(tvecnode(n).left.getcopy,tfornode(arg).right.getcopy)
)
));
);
{ If the calculation is not performed at the end
it is needed to adjust the starting value }
if not docalcatend then
begin
if lnf_backward in tfornode(arg).loopflags then
nt:=addn
else
nt:=subn;
nn:=caddnode.create_internal(nt,
ctypeconvnode.create_internal(nn,voidpointertype),
cordconstnode.create(tcgvecnode(n).get_mul_size,sizeuinttype,false));
end;
addstatement(initcodestatements,cassignmentnode.create(ctemprefnode.create(tempnode),nn));
{ finally replace the node by a temp. ref }
n:=ctypeconvnode.create_internal(cderefnode.create(ctemprefnode.create(tempnode)),n.resultdef);
@ -489,6 +537,7 @@ unit optloop;
initcodestatements:=nil;
calccodestatements:=nil;
deletecodestatements:=nil;
docalcatend:=false;
{ find all expressions being candidates for strength reduction
and replace them }
foreachnodestatic(pm_postprocess,node,@dostrengthreductiontest,node);
@ -511,8 +560,11 @@ unit optloop;
node:=fornode;
loopcode:=internalstatements(loopcodestatements);
if not docalcatend then
addstatement(loopcodestatements,calccode);
addstatement(loopcodestatements,tfornode(node).t2);
addstatement(loopcodestatements,calccode);
if docalcatend then
addstatement(loopcodestatements,calccode);
tfornode(node).t2:=loopcode;
do_firstpass(node);
@ -556,6 +608,9 @@ unit optloop;
function OptimizeInductionVariables(node : tnode) : boolean;
begin
Result:=false;
if not(pi_dfaavailable in current_procinfo.flags) then
exit;
changedforloop:=false;
foreachnodestatic(pm_postprocess,node,@OptimizeInductionVariables_iterforloops,nil);
Result:=changedforloop;