AArch64: remove ConstantIsland pass & put literals in separate section.

This implements the review suggestion to simplify the AArch64 backend. If we
later discover that we *really* need the extra complexity of the
ConstantIslands pass for performance reasons it can be resurrected.

llvm-svn: 175258
diff --git a/llvm/test/CodeGen/AArch64/extern-weak.ll b/llvm/test/CodeGen/AArch64/extern-weak.ll
index 54baab2..2989776 100644
--- a/llvm/test/CodeGen/AArch64/extern-weak.ll
+++ b/llvm/test/CodeGen/AArch64/extern-weak.ll
@@ -6,8 +6,9 @@
 ; The usual ADRP/ADD pair can't be used for a weak reference because it must
 ; evaluate to 0 if the symbol is undefined. We use a litpool entry.
   ret i32()* @var
-; CHECK: ldr x0, .LCPI0_0
-
 ; CHECK: .LCPI0_0:
 ; CHECK-NEXT: .xword var
+
+; CHECK: ldr x0, [{{x[0-9]+}}, #:lo12:.LCPI0_0]
+
 }