implement va_arg for powerpc64 and powerpc64le

Author: folkertdev

compiler/rustc_codegen_llvm/src/va_arg.rs

@@ -475,6 +475,18 @@ pub(super) fn emit_va_arg<'ll, 'tcx>(
         ),
         "aarch64" => emit_aapcs_va_arg(bx, addr, target_ty),
         "s390x" => emit_s390x_va_arg(bx, addr, target_ty),
+        "powerpc64" | "powerpc64le" => emit_ptr_va_arg(
+            bx,
+            addr,
+            target_ty,
+            PassMode::Direct,
+            SlotSize::Bytes8,
+            AllowHigherAlign::Yes,
+            match &**arch {
+                "powerpc64" => ForceRightAdjust::Yes,
+                _ => ForceRightAdjust::No,
+            },
+        ),
         // Windows x86_64
         "x86_64" if target.is_like_windows => {
             let target_ty_size = bx.cx.size_of(target_ty).bytes();