Revision: 14381
Author: [email protected]
Date: Mon Apr 22 09:31:16 2013
Log: Ignore observed Double output in binary operations when all uses
are truncating to Integer32
BUG=v8:2424
Review URL: https://codereview.chromium.org/14320021
http://code.google.com/p/v8/source/detail?r=14381
Modified:
/branches/bleeding_edge/src/hydrogen-instructions.cc
/branches/bleeding_edge/src/hydrogen-instructions.h
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Apr 22
01:00:28 2013
+++ /branches/bleeding_edge/src/hydrogen-instructions.cc Mon Apr 22
09:31:16 2013
@@ -2226,15 +2226,26 @@
new_rep = RepresentationFromUses();
UpdateRepresentation(new_rep, h_infer, "uses");
}
+
+
+bool HBinaryOperation::IgnoreObservedOutputRepresentation(
+ Representation current_rep) {
+ return observed_output_representation_.IsDouble() &&
+ current_rep.IsInteger32() &&
+ // Mul in Integer32 mode would be too precise.
+ !this->IsMul() &&
+ // TODO(jkummerow): Remove blacklisting of Div when the Div
+ // instruction has learned not to deopt when the remainder is
+ // non-zero but all uses are truncating.
+ !this->IsDiv() &&
+ CheckUsesForFlag(kTruncatingToInt32);
+}
Representation HBinaryOperation::RepresentationFromInputs() {
// Determine the worst case of observed input representations and
// the currently assumed output representation.
Representation rep = representation();
- if (observed_output_representation_.is_more_general_than(rep)) {
- rep = observed_output_representation_;
- }
for (int i = 1; i <= 2; ++i) {
Representation input_rep = observed_input_representation(i);
if (input_rep.is_more_general_than(rep)) rep = input_rep;
@@ -2252,6 +2263,13 @@
right()->CheckFlag(kFlexibleRepresentation)) {
rep = right_rep;
}
+ // Consider observed output representation, but ignore it if it's Double,
+ // this instruction is not a division, and all its uses are truncating
+ // to Integer32.
+ if (observed_output_representation_.is_more_general_than(rep) &&
+ !IgnoreObservedOutputRepresentation(rep)) {
+ rep = observed_output_representation_;
+ }
return rep;
}
=======================================
--- /branches/bleeding_edge/src/hydrogen-instructions.h Fri Apr 19 09:46:13
2013
+++ /branches/bleeding_edge/src/hydrogen-instructions.h Mon Apr 22 09:31:16
2013
@@ -3455,6 +3455,8 @@
DECLARE_ABSTRACT_INSTRUCTION(BinaryOperation)
private:
+ bool IgnoreObservedOutputRepresentation(Representation current_rep);
+
Representation observed_input_representation_[2];
Representation observed_output_representation_;
};
--
--
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