Reviewers: fschneider,
Description:
Refactored HInferRepresenation::TryChange a bit, making the heuristics a bit
clearer.
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.)
Please review this at http://codereview.chromium.org/7857033/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/hydrogen.cc
Index: src/hydrogen.cc
===================================================================
--- src/hydrogen.cc (revision 9208)
+++ src/hydrogen.cc (working copy)
@@ -1649,18 +1649,20 @@
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()) {
- return Representation::Integer32();
- }
- }
- if (double_count > 0) return Representation::Double();
+ // 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();
}
--
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