patch codegen_ssa to allow passing ScalarPairs with PassMode::Direct

Author: Firestar99

crates/rustc_codegen_spirv/build.rs

@@ -256,6 +256,33 @@ pub(super) fn elf_e_flags(architecture: Architecture, sess: &Session) -> u32 {",
                 );
             }
 
+            // HACK(firestar99): Undo code cleanup that prevents passing ScalarPairs as `PassMode::Direct`
+            // https://github.com/rust-lang/rust/commit/dfc475d018c780475ea962f15d86cfa05a50a148
+            if relative_path == Path::new("src/mir/mod.rs") {
+                src = src.replace(
+                    "
+                        debug_assert!(bx.is_backend_immediate(arg.layout));
+                        return local(OperandRef {
+                            val: OperandValue::Immediate(llarg),
+                            layout: arg.layout,
+                            move_annotation: None,
+                        });",
+                    "
+                        return local(OperandRef::from_immediate_or_packed_pair(
+                            bx, llarg, arg.layout,
+                        ));",
+                );
+            }
+            if relative_path == Path::new("src/mir/block.rs") {
+                src = src.replace(
+                    r#"
+                PassMode::Direct(_) => (op.immediate(), arg.layout.align.abi, false),
+                PassMode::Ignore | PassMode::Pair(..) => unreachable!("handled above"),"#,
+                    "\
+                _ => (op.immediate_or_packed_pair(bx), arg.layout.align.abi, false),",
+                );
+            }
+
             fs::write(out_path, src)?;
         }
     }

tests/compiletests/ui/lang/core/intrinsics/black_box.stderr

@@ -8,7 +8,7 @@ OpLine %5 41 19
 %10 = OpIAdd  %7  %11 %12
 OpLine %5 47 8
 %13 = OpBitcast  %7  %14
-OpLine %15 1244 17
+OpLine %15 1245 17
 %16 = OpBitcast  %7  %17
 OpLine %5 46 4
 %18 = OpCompositeConstruct  %2  %13 %16 %19 %20 %21 %22 %6 %23 %10 %24 %24 %24