Specialize mint shift code on ia32 for a constant shift amount.

runtime/vm/assembler_ia32_test.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"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/os.h"
@@ skipping 535 matching lines @@
   __ movl(EAX, Immediate(-1));
   __ movl(ECX, Immediate(2));
   __ shll(Address(ESP, 0), ECX);
   __ shld(Address(ESP, 0), EAX);
   __ cmpl(Address(ESP, 0), Immediate(0xF0000003));
   __ j(EQUAL, &donetest15);
   __ int3();
   __ Bind(&donetest15);
   __ addl(ESP, Immediate(kWordSize));
 
+  Label donetest16;
+  __ movl(EDX, Immediate(0x80000000));
+  __ movl(EAX, Immediate(0));
+  __ movl(ECX, Immediate(3));
+  __ sarl(EDX, Immediate(3));
+  __ shrd(EDX, EAX, Immediate(3));
+  __ cmpl(EDX, Immediate(0x1e000000));
+  __ j(EQUAL, &donetest16);
+  __ int3();
+  __ Bind(&donetest16);
+
+  Label donetest17;
+  __ movl(EDX, Immediate(0xFF000000));
+  __ movl(EAX, Immediate(-1));
+  __ shll(EDX, Immediate(2));
+  __ shld(EDX, EAX, Immediate(2));
+  __ cmpl(EDX, Immediate(0xF0000003));
+  __ j(EQUAL, &donetest17);
+  __ int3();
+  __ Bind(&donetest17);
+
   __ movl(EAX, Immediate(0));
   __ ret();
 }
 
 
 ASSEMBLER_TEST_RUN(LogicalOps, test) {
   typedef int (*LogicalOpsCode)();
   EXPECT_EQ(0, reinterpret_cast<LogicalOpsCode>(test->entry())());
 }
 
@@ skipping 2695 matching lines @@
                      FieldAddress(ECX, GrowableObjectArray::data_offset()),
                      EAX);
   __ popl(EAX);
   __ popl(CTX);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32