Reviewers: Sven Panne,
Message:
PTAL.
Description:
Ignore observed Double output in binary operations when all uses are
truncating
to Integer32
BUG=v8:2424
Please review this at https://codereview.chromium.org/14320021/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/hydrogen-instructions.cc
Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index
6496fa8eeb9d96bd3e9e0e0a7827ce41619377fa..f2dc33038024e900318782ef9ef97010ede21722
100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2232,9 +2232,6 @@ 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 +2249,21 @@ Representation
HBinaryOperation::RepresentationFromInputs() {
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)) {
+ bool ignore = false;
+ if (observed_output_representation_.IsDouble() &&
+ rep.IsInteger32() &&
+ // TODO(jkummerow): remove the Div blacklisting when the Div
+ // instruction has learned not to deopt when the remainder is
+ // non-zero but all uses are truncating.
+ !this->IsDiv()) {
+ ignore = CheckUsesForFlag(kTruncatingToInt32);
+ }
+ if (!ignore) rep = observed_output_representation_;
+ }
return rep;
}
--
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