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* optimize a-const1-const2 when const1 and const2 are real constants and fast math is on, part of fixing #39782

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florian 2022-06-17 23:38:29 +02:00
parent d92bc0e760
commit 94665a40d7
1 changed files with 18 additions and 2 deletions
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20
compiler/nadd.pas
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@ -1457,7 +1457,7 @@ implementation
{ slow simplifications and/or more sophisticated transformations which might make debugging harder }
if cs_opt_level2 in current_settings.optimizerswitches then
begin
if nodetype in [addn,muln] then
if nodetype in [addn,muln,subn] then
begin
{ try to fold
op
@ -1470,11 +1470,27 @@ implementation
}
if (left.nodetype=nodetype) and
(((nodetype=addn) and ((rt=stringconstn) or is_constcharnode(right)) and ((taddnode(left).right.nodetype=stringconstn) or is_constcharnode(taddnode(left).right))) or
((nodetype in [addn,muln]) and (cs_opt_fastmath in current_settings.optimizerswitches) and (rt=realconstn) and (taddnode(left).right.nodetype=realconstn))
((nodetype in [addn,muln,subn]) and (cs_opt_fastmath in current_settings.optimizerswitches) and (rt=realconstn) and (taddnode(left).right.nodetype=realconstn))
) and
(compare_defs(resultdef,left.resultdef,nothingn)=te_exact) then
begin
{ SwapRightWithLeftLeft moves the nodes around in way that we need to insert a minus
on left.right: a-b-c becomes b-c-a so we
need
1) insert a minus bevor b
2) make the current node an add node, see below
}
if nodetype=subn then
begin
taddnode(left).right:=cunaryminusnode.create(taddnode(left).right);
do_typecheckpass(taddnode(left).right);
end;
Result:=SwapRightWithLeftLeft;
if nodetype=subn then
begin
Result.nodetype:=addn;
do_typecheckpass(Result);
end;
exit;
end;