Fix a bit of confusion about .set and produce more readable assembly.

Every target we support has support for assembly that looks like

a = b - c
.long a

What is special about MachO is that the above combination suppresses the
production of a relocation.

With this change we avoid producing the intermediary labels when they don't
add any value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220256 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/X86/X86MCInstLower.cpp

@@ -264,7 +264,8 @@ MCOperand X86MCInstLower::LowerSymbolOperand(const MachineOperand &MO,
     Expr = MCBinaryExpr::CreateSub(Expr,
                             MCSymbolRefExpr::Create(MF.getPICBaseSymbol(), Ctx),
                                    Ctx);
-    if (MO.isJTI() && MAI.hasSetDirective()) {
+    if (MO.isJTI()) {
+      assert(MAI.doesSetDirectiveSuppressesReloc());
       // If .set directive is supported, use it to reduce the number of
       // relocations the assembler will generate for differences between
       // local labels. This is only safe when the symbols are in the same