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X64: Do not use an AllocateWithoutSpill register if it is invalid. Abandoned in favor of approach in http://codereview.chromium.org/165525/show (Issue 165526)

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Review URL: http://codereview.chromium.org/164480

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2693 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
whesse@chromium.org 2009-08-17 08:02:07 +00:00
parent 903599a2fc
commit ab041ee4ed
1 changed files with 19 additions and 9 deletions
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28
src/x64/codegen-x64.cc
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@ -3084,26 +3084,36 @@ void CodeGenerator::VisitCountOperation(CountOperation* node) {
is_increment);
}
// If we have a free register, combine the smi and overflow checks.
Result tmp = allocator_->AllocateWithoutSpilling();
ASSERT(kSmiTagMask == 1 && kSmiTag == 0);
__ movl(tmp.reg(), Immediate(kSmiTagMask));
// Smi test.
if (tmp.is_valid()) {
__ movl(tmp.reg(), Immediate(kSmiTagMask));
}
// Try incrementing or decrementing the smi.
__ movq(kScratchRegister, new_value.reg());
if (is_increment) {
__ addl(kScratchRegister, Immediate(Smi::FromInt(1)));
} else {
__ subl(kScratchRegister, Immediate(Smi::FromInt(1)));
}
// deferred->Branch(overflow);
__ cmovl(overflow, kScratchRegister, tmp.reg());
__ testl(kScratchRegister, tmp.reg());
tmp.Unuse();
deferred->Branch(not_zero);
// Go to the deferred case if the result overflows or is non-smi.
if (tmp.is_valid()){
__ cmovl(overflow, kScratchRegister, tmp.reg());
__ testl(kScratchRegister, tmp.reg());
tmp.Unuse();
deferred->Branch(not_zero);
} else {
deferred->Branch(overflow);
__ testl(kScratchRegister, Immediate(kSmiTagMask));
deferred->Branch(not_zero);
}
__ movq(new_value.reg(), kScratchRegister);
deferred->BindExit();
// Postfix: store the old value in the allocated slot under the
// reference.
if (is_postfix) frame_->SetElementAt(target.size(), &old_value);