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+ New optimization: Comparisions with evaluate to true or false if the

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constant is outside the range of type bounds of the left expression.
    I.e. "if a>0" evaluates to true if a is declared with type 1..10,
    as all legal values of a are greater than zero.

git-svn-id: trunk@7603 -
This commit is contained in:
daniel 2007-06-09 14:03:56 +00:00
parent 8bae130fcb
commit 60dee7fcf0
1 changed files with 86 additions and 2 deletions
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88
compiler/nadd.pas
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@ -173,7 +173,6 @@ implementation
end;
end;
{ both are int constants }
if (
(
@ -382,7 +381,92 @@ implementation
end;
result:=t;
exit;
end;
end
{Match against the ranges, i.e.:
var a:1..10;
begin
if a>0 then
... always evaluates to true. (DM)}
else if is_constintnode(left) and (right.resultdef.typ=orddef)
{workaround for u64bit bugs} and (Torddef(right.resultdef).ordtype<>u64bit) then
begin
t:=nil;
lv:=Tordconstnode(left).value;
with Torddef(right.resultdef) do
case nodetype of
ltn:
if lv<low then
t:=Cordconstnode.create(1,booltype,true)
else if lv>=high then
t:=Cordconstnode.create(0,booltype,true);
lten:
if lv<=low then
t:=Cordconstnode.create(1,booltype,true)
else if lv>high then
t:=Cordconstnode.create(0,booltype,true);
gtn:
if lv<=low then
t:=Cordconstnode.create(0,booltype,true)
else if lv>high then
t:=Cordconstnode.create(1,booltype,true);
gten :
if lv<low then
t:=Cordconstnode.create(0,booltype,true)
else if lv>=high then
t:=Cordconstnode.create(1,booltype,true);
equaln:
if (lv<low) or (lv>high) then
t:=Cordconstnode.create(0,booltype,true);
unequaln:
if (lv<low) or (lv>high) then
t:=Cordconstnode.create(1,booltype,true);
end;
if t<>nil then
begin
result:=t;
exit;
end
end
else if (left.resultdef.typ=orddef) and is_constintnode(right)
{workaround for u64bit bugs} and (Torddef(left.resultdef).ordtype<>u64bit) then
begin
t:=nil;
rv:=Tordconstnode(right).value;
with Torddef(left.resultdef) do
case nodetype of
ltn:
if high<rv then
t:=Cordconstnode.create(1,booltype,true)
else if low>=rv then
t:=Cordconstnode.create(0,booltype,true);
lten:
if high<=rv then
t:=Cordconstnode.create(1,booltype,true)
else if low>rv then
t:=Cordconstnode.create(0,booltype,true);
gtn:
if high<=rv then
t:=Cordconstnode.create(0,booltype,true)
else if low>rv then
t:=Cordconstnode.create(1,booltype,true);
gten:
if high<rv then
t:=Cordconstnode.create(0,booltype,true)
else if low>=rv then
t:=Cordconstnode.create(1,booltype,true);
equaln:
if (rv<low) or (rv>high) then
t:=Cordconstnode.create(0,booltype,true);
unequaln:
if (rv<low) or (rv>high) then
t:=Cordconstnode.create(1,booltype,true);
end;
if t<>nil then
begin
result:=t;
exit;
end
end;
{ Add,Sub,Mul with constant 0 or 1? }
if is_constintnode(right) and is_integer(left.resultdef) then