8359386: Fix incorrect value for max_size of C2CodeStub when APX is used

Reviewed-by: thartmann, shade, jbhateja, sviswanathan

Author: Srinivas Vamsi Parasa

src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp

@@ -4655,6 +4655,7 @@ static void convertF2I_slowpath(C2_MacroAssembler& masm, C2GeneralStub<Register,
   __ subptr(rsp, 8);
   __ movdbl(Address(rsp), src);
   __ call(RuntimeAddress(target));
+  // APX REX2 encoding for pop(dst) increases the stub size by 1 byte.
   __ pop(dst);
   __ jmp(stub.continuation());
 #undef __
@@ -4687,7 +4688,9 @@ void C2_MacroAssembler::convertF2I(BasicType dst_bt, BasicType src_bt, Register
     }
   }
 
-  auto stub = C2CodeStub::make<Register, XMMRegister, address>(dst, src, slowpath_target, 23, convertF2I_slowpath);
+  // Using the APX extended general purpose registers increases the instruction encoding size by 1 byte.
+  int max_size = 23 + (UseAPX ? 1 : 0);
+  auto stub = C2CodeStub::make<Register, XMMRegister, address>(dst, src, slowpath_target, max_size, convertF2I_slowpath);
   jcc(Assembler::equal, stub->entry());
   bind(stub->continuation());
 }