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Refactored HInferRepresenation::TryChange a bit, making the heuristics a bit clearer.

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Removed an unneeded check for phis: There are never HValues in the work list
which are not convertible to integer and are not a phi. (But even if they were,
ignoring IsConvertibleToInteger() then looks like the wrong thing to do.)
Review URL: http://codereview.chromium.org/7857033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9225 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
svenpanne@chromium.org 2011-09-12 09:24:18 +00:00
parent faa82f6363
commit baab04283d
1 changed files with 11 additions and 9 deletions
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16
src/hydrogen.cc
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@ -1649,18 +1649,20 @@ Representation HInferRepresentation::TryChange(HValue* value) {
int non_tagged_count = double_count + int32_count;
// If a non-loop phi has tagged uses, don't convert it to untagged.
if (value->IsPhi() && !value->block()->IsLoopHeader()) {
if (tagged_count > 0) return Representation::None();
if (value->IsPhi() && !value->block()->IsLoopHeader() && tagged_count > 0) {
return Representation::None();
}
if (non_tagged_count >= tagged_count) {
if (int32_count > 0) {
if (!value->IsPhi() || value->IsConvertibleToInteger()) {
// Prefer unboxing over boxing, the latter is more expensive.
if (tagged_count > non_tagged_count) Representation::None();
// Prefer Integer32 over Double, if possible.
if (int32_count > 0 && value->IsConvertibleToInteger()) {
return Representation::Integer32();
}
}
if (double_count > 0) return Representation::Double();
}
return Representation::None();
}