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* handle short boolean evaluation correctly when doing node cse

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git-svn-id: trunk@14691 -
This commit is contained in:
florian 2010-01-17 10:08:37 +00:00
parent 3c7f726f98
commit 49f9695cf5
2 changed files with 64 additions and 7 deletions
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1
compiler/optbase.pas
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@ -42,6 +42,7 @@ unit optbase;
use : tdfaset;
life : tdfaset;
defsum : tdfaset;
avail : tdfaset;
end;
poptinfo = ^toptinfo;

70
compiler/optcse.pas
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@ -54,9 +54,11 @@ unit optcse;
cclasses,
verbose,
nutils,
nbas,nld,ninl,ncal,
nbas,nld,ninl,ncal,ncnv,nadd,
pass_1,
symconst,symtype,symdef;
symconst,symtype,symdef,
defutil,
optbase;
const
cseinvariant : set of tnodetype = [loadn,addn,muln,subn,divn,slashn,modn,andn,orn,xorn,notn,vecn,
@ -84,13 +86,31 @@ unit optcse;
locationlist : tfplist;
equalto : tfplist;
refs : tfplist;
avail : TDFASet;
end;
plists = ^tlists;
{ collectnodes needs the address of itself to call foreachnodestatic,
so we need a wrapper because @<func> inside <func doesn't work }
function collectnodes(var n:tnode; arg: pointer) : foreachnoderesult;forward;
function collectnodes2(var n:tnode; arg: pointer) : foreachnoderesult;
begin
result:=collectnodes(n,arg);
end;
function collectnodes(var n:tnode; arg: pointer) : foreachnoderesult;
procedure AddAvail(child : tnode);
begin
if assigned(child) and assigned(child.optinfo) then
DFASetIncludeSet(n.optinfo^.avail,child.optinfo^.avail);
end;
var
i : longint;
i,j : longint;
begin
result:=fen_false;
{ don't add the tree below an untyped const parameter: there is
@ -111,16 +131,39 @@ unit optcse;
not(n.resultdef.typ in [arraydef,recorddef]) and
{ adding tempref nodes is worthless but their complexity is probably <= 1 anyways }
not(n.nodetype in [temprefn]) and
{ node worth to add? }
(node_complexity(n)>1) then
{ node worth to add?
We consider every node because even loading a variables from
a register instead of memory is more beneficial. This behaviour should
not increase register pressure because if a variable is already
in a register, the reg. allocator can merge the nodes. If a variable
is loaded from memory, loading this variable and spilling another register
should not add a speed penalty.
Const nodes however are only considered if their complexity is >1
This might be the case for the risc architectures if they need
more than one instruction to load this particular value
}
(not(is_constnode(n)) or (node_complexity(n)>1)) then
begin
plists(arg)^.nodelist.Add(n);
plists(arg)^.locationlist.Add(@n);
plists(arg)^.refs.Add(nil);
plists(arg)^.equalto.Add(pointer(-1));
{
{ setup set of available expressions }
n.allocoptinfo;
n.optinfo^.avail:=nil;
DFASetInclude(n.optinfo^.avail,plists(arg)^.nodelist.count-1);
}
DFASetInclude(plists(arg)^.avail,plists(arg)^.nodelist.count-1);
for i:=0 to plists(arg)^.nodelist.count-2 do
begin
if tnode(plists(arg)^.nodelist[i]).isequal(n) then
if tnode(plists(arg)^.nodelist[i]).isequal(n) and DFASetIn(plists(arg)^.avail,i) then
begin
{ use always the first occurence }
if ptrint(plists(arg)^.equalto[i])<>-1 then
@ -128,10 +171,23 @@ unit optcse;
else
plists(arg)^.equalto[plists(arg)^.nodelist.count-1]:=pointer(i);
plists(arg)^.refs[i]:=pointer(plists(arg)^.refs[i])+1;
exit;
break;
end;
end;
{ boolean and/or require a special handling: after evaluating the and/or node,
the expressions of the right side might not be available due to short boolean
evaluation, so after handling the right side, mark those expressions
as unavailable }
if (n.nodetype in [orn,andn]) and is_boolean(taddnode(n).left.resultdef) then
begin
foreachnodestatic(pm_postprocess,taddnode(n).left,@collectnodes2,arg);
j:=plists(arg)^.nodelist.count;
foreachnodestatic(pm_postprocess,taddnode(n).right,@collectnodes2,arg);
for i:=j to plists(arg)^.nodelist.count-1 do
DFASetExclude(plists(arg)^.avail,i);
result:=fen_norecurse_false;
end;
end;
end;