Implement some conditional moves instructions for ia32/x64. Use them in MinMax instruction implemen…

runtime/vm/assembler_x64.cc

Index: runtime/vm/assembler_x64.cc
===================================================================
--- runtime/vm/assembler_x64.cc	(revision 25648)
+++ runtime/vm/assembler_x64.cc	(working copy)
@@ -406,6 +406,27 @@
 }
 
 
+void Assembler::cmovgeq(Register dst, Register src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  Operand operand(src);
+  EmitOperandREX(dst, operand, REX_W);
+  EmitUint8(0x0F);
+  EmitUint8(0x4D);
+  EmitOperand(dst & 7, operand);
+}
+
+
+void Assembler::cmovlessq(Register dst, Register src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  Operand operand(src);
+  EmitOperandREX(dst, operand, REX_W);
+  EmitUint8(0x0F);
+  EmitUint8(0x4C);
+  EmitOperand(dst & 7, operand);
+}
+
+
+
 void Assembler::movss(XmmRegister dst, const Address& src) {
   ASSERT(dst <= XMM15);
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);