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			36 lines
		
	
	
		
			1.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			36 lines
		
	
	
		
			1.0 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
| // Copyright 2015 the V8 project authors. All rights reserved.
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| // Use of this source code is governed by a BSD-style license that can be
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| // found in the LICENSE file.
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| 
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| // Flags: --allow-natives-syntax
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| 
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| function boom(a1, a2) {
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|   // Do something with a2 that needs a map check (for DOUBLE_ELEMENTS).
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|   var s = a2[0];
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|   // Emit a load that transitions a1 to PACKED_ELEMENTS.
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|   var t = a1[0];
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|   // Emit a store to a2 that assumes DOUBLE_ELEMENTS.
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|   // The map check is considered redundant and will be eliminated.
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|   a2[0] = 0.3;
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| }
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| 
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| // Prepare type feedback for the "t = a1[0]" load: fast elements.
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| var fast_elem = new Array(1);
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| fast_elem[0] = "tagged";
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| boom(fast_elem, [1]);
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| 
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| // Prepare type feedback for the "a2[0] = 0.3" store: double elements.
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| var double_elem = new Array(1);
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| double_elem[0] = 0.1;
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| boom(double_elem, double_elem);
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| 
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| // Reset |double_elem| and go have a party.
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| double_elem = new Array(10);
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| double_elem[0] = 0.1;
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| 
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| %OptimizeFunctionOnNextCall(boom);
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| boom(double_elem, double_elem);
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| 
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| assertEquals(0.3, double_elem[0]);
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| assertEquals(undefined, double_elem[1]);
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