Revision: 2693
Author: [email protected]
Date: Mon Aug 17 01:02:07 2009
Log: 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)
Review URL: http://codereview.chromium.org/164480
http://code.google.com/p/v8/source/detail?r=2693
Modified:
/branches/bleeding_edge/src/x64/codegen-x64.cc
=======================================
--- /branches/bleeding_edge/src/x64/codegen-x64.cc Thu Aug 13 01:00:04 2009
+++ /branches/bleeding_edge/src/x64/codegen-x64.cc Mon Aug 17 01:02:07 2009
@@ -3084,25 +3084,35 @@
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);
- __ movq(new_value.reg(), kScratchRegister);
-
- deferred->BindExit();
-
+
+ // 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.
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