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* don't do cse on simple local/para variables

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git-svn-id: trunk@14765 -
This commit is contained in:
florian 2010-01-21 19:30:25 +00:00
parent 69a23fe32a
commit 29961c1b8c
1 changed files with 12 additions and 2 deletions
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14
compiler/optcse.pas
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@ -54,6 +54,7 @@ unit optcse;
cclasses,
verbose,
nutils,
procinfo,
nbas,nld,ninl,ncal,ncnv,nadd,
pass_1,
symconst,symtype,symdef,
@ -127,18 +128,27 @@ unit optcse;
{ node worth to add?
We consider every node because even loading a variables from
We consider almost 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.
}
{
load nodes are not considered if they load para or local symbols from the
current stack frame, those are in registers anyways if possible
}
(not(n.nodetype=loadn) or
not(tloadnode(n).symtableentry.typ in [paravarsym,localvarsym]) or
(tloadnode(n).symtable.symtablelevel<>current_procinfo.procdef.parast.symtablelevel)
) and
{
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);