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* optimize some more range checks away again, fixes 64bit cpu issues

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git-svn-id: trunk@2621 -
This commit is contained in:
Jonas Maebe 2006-02-18 20:59:44 +00:00
parent eaf18ed0d1
commit cf6968ae95
1 changed files with 45 additions and 2 deletions
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47
compiler/cgobj.pas
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@ -1647,7 +1647,8 @@ implementation
hreg : tregister;
lto,hto,
lfrom,hfrom : TConstExprInt;
from_signed: boolean;
fromsize, tosize: cardinal;
from_signed, to_signed: boolean;
begin
{ range checking on and range checkable value? }
if not(cs_check_range in aktlocalswitches) or
@ -1666,6 +1667,7 @@ implementation
getrange(fromdef,lfrom,hfrom);
getrange(todef,lto,hto);
from_signed := is_signed(fromdef);
to_signed := is_signed(todef);
{ 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) }
@ -1693,6 +1695,47 @@ implementation
exit;
{$endif cpu64bit}
{ optimize some range checks away in safe cases }
fromsize := fromdef.size;
tosize := todef.size;
if ((from_signed = to_signed) or
(not from_signed)) and
(lto<=lfrom) and (hto>=hfrom) and
(fromsize <= tosize) then
begin
{ if fromsize < tosize, and both have the same signed-ness or }
{ fromdef is unsigned, then all bit patterns from fromdef are }
{ valid for todef as well }
if (fromsize < tosize) then
exit;
if (fromsize = tosize) and
(from_signed = to_signed) then
{ only optimize away if all bit patterns which fit in fromsize }
{ are valid for the todef }
begin
{$ifopt Q+}
{$defined overflowon}
{$Q-}
{$endif}
if to_signed then
begin
if (lto = (-(int64(1) << (tosize * 4)))) and
(hto = (int64(1) << (tosize * 4) - 1)) then
exit
end
else
begin
if (lto = 0) and
(qword(hto) = qword((int64(1) << (tosize * 8)) - 1)) then
exit
end;
{$ifdef overflowon}
{$Q+}
{$undef overflowon}
{$endif}
end
end;
{ generate the rangecheck code for the def where we are going to }
{ store the result }
@ -1704,7 +1747,7 @@ implementation
{ the parts < 0 and > maxlongint out }
{ is_signed now also works for arrays (it checks the rangetype) (JM) }
if from_signed xor is_signed(todef) then
if from_signed xor to_signed then
begin
if from_signed then
{ from is signed, to is unsigned }