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* in x:=f(..), we only checked for aliasing between x and any parameters of

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f(..) before using x directly as function result for f(..) (instead of a
    temp) in case the function result of temp is passed via a hiddel
    call-by-reference parameter. After all, if the result is returned by
    value, then any changes to the function result inside the callee code
    won't affect whatever we will assign the result to until the callee
    has returned. However, this is not true in case of inlining: then
    the replaced function result node will be substituted directly in the
    inlined code -> also check for aliasing in that case.
   o fixes test/toperator5.pp on x86-64

git-svn-id: trunk@34893 -
This commit is contained in:
Jonas Maebe 2016-11-13 16:06:35 +00:00
parent c3aa9e2890
commit 7a57161b6d
1 changed files with 23 additions and 10 deletions
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33
compiler/ncal.pas
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@ -2956,17 +2956,30 @@ implementation
{ remove possible typecasts }
realassignmenttarget:=actualtargetnode(@aktassignmentnode.left)^;
{ when it is not passed in a parameter it will only be used after the
function call }
{ when the result is returned by value (instead of by writing it to the
address passed in a hidden parameter), aktassignmentnode.left will
only be changed once the function has returned and we don't have to
perform any checks regarding whether it may alias with one of the
parameters -- unless this is an inline function, in which case
writes to the function result will directly change it and we do have
to check for potential aliasing }
if not paramanager.ret_in_param(resultdef,procdefinition) then
begin
{ don't replace the function result if we are inlining and if the destination is complex, this
could lead to lengthy code in case the function result is used often and it is assigned e.g.
to a threadvar }
result:=not(cnf_do_inline in callnodeflags) or
(node_complexity(aktassignmentnode.left)<=1);
exit;
end;
begin
if not(cnf_do_inline in callnodeflags) then
begin
result:=true;
exit;
end
else
begin
{ don't replace the function result if we are inlining and if
the destination is complex, this could lead to lengthy
code in case the function result is used often and it is
assigned e.g. to a threadvar }
if node_complexity(aktassignmentnode.left)>1 then
exit;
end;
end;
{ if the result is the same as the self parameter (in case of objects),
we can't optimise. We have to check this explicitly becaise