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* more fixes (to the optimizations) for range check code generation

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git-svn-id: trunk@2803 -
This commit is contained in:
tom_at_work 2006-03-07 22:52:03 +00:00
parent 23fda6dc1c
commit cb807cb2af
1 changed files with 14 additions and 4 deletions

18
compiler/cgobj.pas
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@ -1673,6 +1673,7 @@ implementation
if (todef.deftype = arraydef) then
todef := tarraydef(todef).rangetype.def;
{ no range check if from and to are equal and are both longint/dword }
{ no range check if from and to are equal and are both longint/dword }
{ (if we have a 32bit processor) or int64/qword, since such }
{ operations can at most cause overflows (JM) }
{ Note that these checks are mostly processor independent, they only }
@ -1685,7 +1686,10 @@ implementation
(hfrom = high(int64))) or
((torddef(fromdef).typ = u64bit) and
(lfrom = low(qword)) and
(hfrom = high(qword)))))) then
(hfrom = high(qword))) or
((torddef(fromdef).typ = scurrency) and
(lfrom = low(int64)) and
(hfrom = high(int64)))))) then
exit;
{$else cpu64bit}
if (fromdef = todef) and
@ -1723,14 +1727,20 @@ implementation
{$endif}
if to_signed then
begin
if (lto = (-(int64(1) << (tosize * 4)))) and
(hto = (int64(1) << (tosize * 4) - 1)) then
{ calculation of the low/high ranges must not overflow 64 bit
otherwise we end up comparing with zero for 64 bit data types on
64 bit processors }
if (lto = (int64(-1) << (tosize * 8 - 1))) and
(hto = (-((int64(-1) << (tosize * 8 - 1))+1))) then
exit
end
else
begin
{ calculation of the low/high ranges must not overflow 64 bit
otherwise we end up having all zeros for 64 bit data types on
64 bit processors }
if (lto = 0) and
(qword(hto) = qword((int64(1) << (tosize * 8)) - 1)) then
(qword(hto) = (qword(-1) >> (64-(tosize * 8))) ) then
exit
end;
{$ifdef overflowon}