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+ more unary minus optimizations

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* test extended
This commit is contained in:
florian 2021-09-21 23:09:33 +02:00
parent 781da5e60d
commit 69d5d648a9
2 changed files with 31 additions and 0 deletions
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17
compiler/nmat.pas
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@ -972,6 +972,23 @@ implementation
exit;
end;
{
-(-left*right) or -(left*-right) => right*left
this operation is always valid as reals do not use a two's complement representation for negative
numbers, -real means just flip the sign bit
}
if (left.nodetype=muln) and ((taddnode(left).left.nodetype=unaryminusn)) then
begin
result:=caddnode.create(muln,taddnode(left).right.getcopy,tunaryminusnode(taddnode(left).left).left.getcopy);
exit;
end;
if (left.nodetype=muln) and ((taddnode(left).right.nodetype=unaryminusn)) then
begin
result:=caddnode.create(muln,taddnode(left).left.getcopy,tunaryminusnode(taddnode(left).right).left.getcopy);
exit;
end;
{ --node => node
this operation is always valid as reals do not use a two's complement representation for negative
numbers, -real means just flip the sign bit

14
tests/tbs/tb0685.pp
View File

@ -44,5 +44,19 @@ begin
if (d3<>0.0) or not(TDoubleRec(d3).Sign) then
halt(7);
d1:=1.0;
d2:=2.0;
d3:=-(d2*-d1);
writeln(d3);
if (d3<>2.0) or (TDoubleRec(d3).Sign) then
halt(8);
d1:=1.0;
d2:=2.0;
d3:=-(-d2*d1);
writeln(d3);
if (d3<>2.0) or (TDoubleRec(d3).Sign) then
halt(9);
writeln('ok');
end.