From b3455d2dc8c962c6ec4a7e1f512371428a26c330 Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Tue, 9 May 2023 21:25:54 +0000
Subject: [PATCH] `rustc_codegen_cranelift`: bug on tail calls

---
 compiler/rustc_codegen_cranelift/src/base.rs     | 5 +++++
 compiler/rustc_codegen_cranelift/src/constant.rs | 1 +
 2 files changed, 6 insertions(+)

diff --git a/compiler/rustc_codegen_cranelift/src/base.rs b/compiler/rustc_codegen_cranelift/src/base.rs
index ce10780f9de12..d8fd00e50d92f 100644
--- a/compiler/rustc_codegen_cranelift/src/base.rs
+++ b/compiler/rustc_codegen_cranelift/src/base.rs
@@ -434,6 +434,11 @@ fn codegen_fn_body(fx: &mut FunctionCx<'_, '_, '_>, start_block: Block) {
                     )
                 });
             }
+            // FIXME(explicit_tail_calls): add support for tail calls to the cranelift backend, once cranelift supports tail calls
+            TerminatorKind::TailCall { fn_span, .. } => span_bug!(
+                *fn_span,
+                "tail calls are not yet supported in `rustc_codegen_cranelift` backend"
+            ),
             TerminatorKind::InlineAsm {
                 template,
                 operands,
diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 427340c333e5a..7ba56d1c04d05 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -566,6 +566,7 @@ pub(crate) fn mir_operand_get_const_val<'tcx>(
                     {
                         return None;
                     }
+                    TerminatorKind::TailCall { .. } => return None,
                     TerminatorKind::Call { .. } => {}
                 }
             }