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

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git-svn-id: trunk@14765 -
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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, cclasses,
verbose, verbose,
nutils, nutils,
procinfo,
nbas,nld,ninl,ncal,ncnv,nadd, nbas,nld,ninl,ncal,ncnv,nadd,
pass_1, pass_1,
symconst,symtype,symdef, symconst,symtype,symdef,
@ -127,18 +128,27 @@ unit optcse;
{ node worth to add? { 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 a register instead of memory is more beneficial. This behaviour should
not increase register pressure because if a variable is already not increase register pressure because if a variable is already
in a register, the reg. allocator can merge the nodes. If a variable in a register, the reg. allocator can merge the nodes. If a variable
is loaded from memory, loading this variable and spilling another register is loaded from memory, loading this variable and spilling another register
should not add a speed penalty. 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 Const nodes however are only considered if their complexity is >1
This might be the case for the risc architectures if they need This might be the case for the risc architectures if they need
more than one instruction to load this particular value more than one instruction to load this particular value
} }
(not(is_constnode(n)) or (node_complexity(n)>1)) then (not(is_constnode(n)) or (node_complexity(n)>1)) then
begin begin
plists(arg)^.nodelist.Add(n); plists(arg)^.nodelist.Add(n);