Author: whessev8
Date: Mon Jan 26 01:15:48 2009
New Revision: 1143
Modified:
branches/bleeding_edge/src/codegen-ia32.cc
Log:
Revert change to Smi check that was a performance regression.
Review URL: http://codereview.chromium.org/18582
Modified: branches/bleeding_edge/src/codegen-ia32.cc
==============================================================================
--- branches/bleeding_edge/src/codegen-ia32.cc (original)
+++ branches/bleeding_edge/src/codegen-ia32.cc Mon Jan 26 01:15:48 2009
@@ -1127,14 +1127,14 @@
__ j(not_zero, deferred->enter(), not_taken);
__ sar(ebx, kSmiTagSize);
__ shl(ebx, shift_value);
- // Convert the int to a Smi, and check that it is in
- // the range of valid Smis.
- ASSERT(kSmiTagSize == times_2); // Adjust code if not true.
- ASSERT(kSmiTag == 0); // Adjust code if not true.
- __ add(ebx, Operand(ebx));
- __ j(overflow, deferred->enter(), not_taken);
- __ mov(eax, Operand(ebx));
-
+ // This is the Smi check for the shifted result.
+ // After signed subtraction of 0xc0000000, the valid
+ // Smis are positive.
+ __ cmp(ebx, 0xc0000000);
+ __ j(sign, deferred->enter(), not_taken);
+ // tag result and store it in TOS (eax)
+ ASSERT(kSmiTagSize == times_2); // adjust code if not the case
+ __ lea(eax, Operand(ebx, ebx, times_1, kSmiTag));
__ bind(deferred->exit());
frame_->Push(eax);
}
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