Uses a conditional move for usage counter increment instead of a branch

runtime/vm/assembler_ia32_test.cc

Index: runtime/vm/assembler_ia32_test.cc
===================================================================
--- runtime/vm/assembler_ia32_test.cc	(revision 38122)
+++ runtime/vm/assembler_ia32_test.cc	(working copy)
@@ -3019,6 +3019,27 @@
 }
 
 
+// Return 1 if overflow, 0 if no overflow.
+ASSEMBLER_TEST_GENERATE(ConditionalMovesNoOverflow, assembler) {
+  __ movl(EDX, Address(ESP, 1 * kWordSize));
+  __ addl(EDX, Address(ESP, 2 * kWordSize));
+  __ movl(EAX, Immediate(1));
+  __ movl(ECX, Immediate(0));
+  __ cmovno(EAX, ECX);
+  __ ret();
+}
+
+
+ASSEMBLER_TEST_RUN(ConditionalMovesNoOverflow, test) {
+  typedef int (*ConditionalMovesNoOverflowCode)(int i, int j);
+  int res = reinterpret_cast<ConditionalMovesNoOverflowCode>(
+      test->entry())(0x7fffffff, 2);
+  EXPECT_EQ(1, res);
+  res = reinterpret_cast<ConditionalMovesNoOverflowCode>(test->entry())(1, 1);
+  EXPECT_EQ(0, res);
+}
+
+
 // Return 1 if equal, 0 if not equal.
 ASSEMBLER_TEST_GENERATE(ConditionalMovesEqual, assembler) {
   __ xorl(EAX, EAX);