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Optimization: Do not assign an environment to LBranch when are sure that we will never deopt later.

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Review URL: http://codereview.chromium.org/7524025

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8760 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
svenpanne@chromium.org 2011-07-28 14:56:08 +00:00
parent d9c2e28a32
commit 3ce397f975
1 changed files with 7 additions and 1 deletions
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8
src/ia32/lithium-ia32.cc
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@ -1042,9 +1042,15 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr) {
return new LGoto(successor->block_id()); return new LGoto(successor->block_id());
} }
ToBooleanStub::Types expected = instr->expected_input_types(); ToBooleanStub::Types expected = instr->expected_input_types();
// We need a temporary register when we have to access the map *or* we have
// no type info yet, in which case we handle all cases (including the ones
// involving maps).
bool needs_temp = expected.NeedsMap() || expected.IsEmpty(); bool needs_temp = expected.NeedsMap() || expected.IsEmpty();
LOperand* temp = needs_temp ? TempRegister() : NULL; LOperand* temp = needs_temp ? TempRegister() : NULL;
return AssignEnvironment(new LBranch(UseRegister(v), temp)); LInstruction* branch = new LBranch(UseRegister(v), temp);
// When we handle all cases, we never deopt, so we don't need to assign the
// environment then.
return expected.IsAll() ? branch : AssignEnvironment(branch);
} }