Add range to kBIT_AND with positive constants. Use that range to eliminate compares in left shifts.

runtime/vm/intermediate_language_ia32.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "lib/error.h"
@@ skipping 1686 matching lines @@
       __ SmiUntag(left);
       __ sarl(left, right);
       __ SmiTag(left);
       break;
     }
     case Token::kSHL: {
       Register temp = locs()->temp(0).reg();
       Label call_method, done;
       // Check if count too large for handling it inlined.
       __ movl(temp, left);
-      __ cmpl(right,
+      Range* right_range = this->right()->definition()->range();
+      const bool right_needs_check =
+          (right_range == NULL) || !right_range->IsWithin(0, (Smi::kBits - 1));
+      if (right_needs_check) {
+        __ cmpl(right,
           Immediate(reinterpret_cast<int32_t>(Smi::New(Smi::kBits))));
-      __ j(ABOVE_EQUAL, &call_method, Assembler::kNearJump);
+        __ j(ABOVE_EQUAL, &call_method, Assembler::kNearJump);
+      }
       Register right_temp = locs()->temp(1).reg();
       ASSERT(right_temp == ECX);  // Count must be in ECX
       __ movl(right_temp, right);
       __ SmiUntag(right_temp);
       // Overflow test (preserve temp and right);
       __ shll(left, right_temp);
       __ sarl(left, right_temp);
       __ cmpl(left, temp);
       __ j(NOT_EQUAL, &call_method, Assembler::kNearJump);  // Overflow.
       // Shift for result now we know there is no overflow.
@@ skipping 826 matching lines @@
   __ pcmpeqq(XMM0, XMM0);  // Generate all 1's.
   __ pxor(value, XMM0);
 }
 
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_X64