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* handle constant folding correctly for <pointer>+<ord. constant>+<ord. constant>, resolves #39332

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florian 2021-09-01 21:32:27 +02:00
parent cb22b7a1d5
commit 3069d74ecc
2 changed files with 45 additions and 1 deletions
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5
compiler/nadd.pas
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@ -541,7 +541,10 @@ implementation
but this is only useful if no pointer operation is done }
left:=ctypeconvnode.create_internal(left,resultdef);
do_typecheckpass(left);
end;
end
else if tpointerdef(resultdef).pointeddef.size>1 then
{ the constants were already multiplied by the pointer element size }
left:=cmoddivnode.create(divn,left,cordconstnode.create(tpointerdef(resultdef).pointeddef.size,left.resultdef,false));
right:=left;
left:=hp;
result:=GetCopyAndTypeCheck;

41
tests/webtbs/tw39332.pp Normal file
View File

@ -0,0 +1,41 @@
{ %OPT=-O3 }
{$mode objfpc} {$h+} {$typedaddress on}
type
pBaseType = ^BaseType;
BaseType = uint32; // can be replaced with an arbitrary-sized array or record
procedure Check(pstart, px: pBaseType; refIx: SizeInt; const desc: string);
var
ix: SizeInt;
begin
ix := px - pstart;
writeln(desc, ' points at element #', ix);
if ix = refIx then
writeln('ok')
else
begin
writeln('WRONG, must be #', refIx);
halt(1);
end;
writeln;
end;
var
x: array[0 .. 19] of BaseType;
p: pBaseType;
begin
p := pBaseType(x);
Check(p, p + 2, 2, 'p + 2');
Check(p, p + 2 + 3, 5, 'p + 2 + 3');
Check(p, p + 2 + 3 + 5, 10, 'p + 2 + 3 + 5');
// These casts don't help.
Check(p, pBaseType(pBaseType(p + 2) + 3) + 5, 10, 'pBaseType(pBaseType(p + 2) + 3) + 5');
// These work, but prevent constant folding.
Check(p, pBaseType(pointer(pBaseType(pointer(p + 2)) + 3)) + 5, 10, 'pBaseType(pointer(pBaseType(pointer(p + 2)) + 3)) + 5');
Check(p, p + (2 + 3 + 5), 10, 'p + (2 + 3 + 5)');
Check(p, p + 2 + 3 + 5 + 7, 17, 'p + 2 + 3 + 5 + 7');
end.