Reviewers: Lasse Reichstein,
Description:
Very small optimization of ARM compare stub.
Please review this at http://codereview.chromium.org/551048
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/arm/codegen-arm.cc
Index: src/arm/codegen-arm.cc
===================================================================
--- src/arm/codegen-arm.cc (revision 3618)
+++ src/arm/codegen-arm.cc (working copy)
@@ -4909,13 +4909,14 @@
Register lhs_mantissa = exp_first ? r1 : r0;
Register rhs_mantissa = exp_first ? r3 : r2;
Label one_is_nan, neither_is_nan;
+ Label rhs_not_nan_exp_mask_is_loaded;
Register exp_mask_reg = r5;
__ mov(exp_mask_reg, Operand(HeapNumber::kExponentMask));
__ and_(r4, rhs_exponent, Operand(exp_mask_reg));
__ cmp(r4, Operand(exp_mask_reg));
- __ b(ne, rhs_not_nan);
+ __ b(ne, &rhs_not_nan_exp_mask_is_loaded);
__ mov(r4,
Operand(rhs_exponent, LSL, HeapNumber::kNonMantissaBitsInTopWord),
SetCC);
@@ -4925,6 +4926,7 @@
__ bind(rhs_not_nan);
__ mov(exp_mask_reg, Operand(HeapNumber::kExponentMask));
+ __ bind(&rhs_not_nan_exp_mask_is_loaded);
__ and_(r4, lhs_exponent, Operand(exp_mask_reg));
__ cmp(r4, Operand(exp_mask_reg));
__ b(ne, &neither_is_nan);
@@ -5036,9 +5038,10 @@
Label* both_loaded_as_doubles,
Label* not_heap_numbers,
Label* slow) {
- __ CompareObjectType(r0, r2, r2, HEAP_NUMBER_TYPE);
+ __ CompareObjectType(r0, r3, r2, HEAP_NUMBER_TYPE);
__ b(ne, not_heap_numbers);
- __ CompareObjectType(r1, r3, r3, HEAP_NUMBER_TYPE);
+ __ ldr(r2, FieldMemOperand(r1, HeapObject::kMapOffset));
+ __ cmp(r2, r3);
__ b(ne, slow); // First was a heap number, second wasn't. Go slow
case.
// Both are heap numbers. Load them up then jump to the code we have
@@ -5139,7 +5142,7 @@
// Check for heap-number-heap-number comparison. Can jump to slow case,
// or load both doubles into r0, r1, r2, r3 and jump to the code that
handles
// that case. If the inputs are not doubles then jumps to
check_for_symbols.
- // In this case r2 will contain the type of r0.
+ // In this case r2 will contain the type of r0. Never falls through.
EmitCheckForTwoHeapNumbers(masm,
&both_loaded_as_doubles,
&check_for_symbols,
--
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