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* more robust code for constant propagation in for loops

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florian 2022-05-21 22:31:51 +02:00
parent f1cb5d8f71
commit 91481a5fae
1 changed files with 21 additions and 15 deletions
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36
compiler/optconstprop.pas
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@ -132,24 +132,30 @@ unit optconstprop;
begin
result:=replaceBasicAssign(tfornode(n).right, arg, tree_modified);
if result then
replaceBasicAssign(tfornode(n).t1, arg, tree_modified2);
tree_modified:=tree_modified or tree_modified2;
if pi_dfaavailable in current_procinfo.flags then
begin
CalcDefSum(tfornode(n).t2);
{ the constant can propagete if is is not the counter variable ... }
if not(tassignmentnode(arg).left.isequal(tfornode(n).left)) and
{ if it is a temprefn or its address is not taken in case of loadn }
((tassignmentnode(arg).left.nodetype=temprefn) or not(tabstractvarsym(tloadnode(tassignmentnode(arg).left).symtableentry).addr_taken)) and
{ and no definition in the loop? }
not(DFASetIn(tfornode(n).t2.optinfo^.defsum,tassignmentnode(arg).left.optinfo^.index)) then
{ play safe and set the result which is check below }
result:=replaceBasicAssign(tfornode(n).t1, arg, tree_modified2);
tree_modified:=tree_modified or tree_modified2;
if result and (pi_dfaavailable in current_procinfo.flags) then
begin
replaceBasicAssign(tfornode(n).t2, arg, tree_modified3);
tree_modified:=tree_modified or tree_modified3;
end;
CalcDefSum(tfornode(n).t2);
{ the constant can propagete if is is not the counter variable ... }
if not(tassignmentnode(arg).left.isequal(tfornode(n).left)) and
{ if it is a temprefn or its address is not taken in case of loadn }
((tassignmentnode(arg).left.nodetype=temprefn) or not(tabstractvarsym(tloadnode(tassignmentnode(arg).left).symtableentry).addr_taken)) and
{ and no definition in the loop? }
not(DFASetIn(tfornode(n).t2.optinfo^.defsum,tassignmentnode(arg).left.optinfo^.index)) then
begin
replaceBasicAssign(tfornode(n).t2, arg, tree_modified3);
tree_modified:=tree_modified or tree_modified3;
result:=false;
end
else
result:=false;
end
else
result:=false;
end;
{ after a for node we cannot continue with our simple approach }
result:=false;
end
else if n.nodetype=blockn then
begin