Rollup merge of #104605 - RalfJung:clf_consts, r=bjorn3

deduplicate constant evaluation in cranelift backend

The cranelift backend had two matches on `ConstantKind`, which can be avoided, and used this `eval_for_mir` that nothing else uses... this makes things more consistent with the (better-tested) LLVM backend.

I noticed this because cranelift was the only user of `eval_for_mir`. However `try_eval_for_mir` still has one other user in `eval`... the odd thing is that the interpreter has its own `eval_mir_constant` which seems to duplicate the same functionality and does not use `try_eval_for_mir`. No idea what is happening here.

r? ``@bjorn3``
Cc ``@lcnr``

1 files changed, 8 insertions, 1 deletions

diff --git a/compiler/rustc_codegen_ssa/src/mir/constant.rs b/compiler/rustc_codegen_ssa/src/mir/constant.rs
index 4c6ab457c49..53ff3c24096 100644
--- a/compiler/rustc_codegen_ssa/src/mir/constant.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/constant.rs
@@ -42,7 +42,14 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         };
 
         self.cx.tcx().const_eval_resolve(ty::ParamEnv::reveal_all(), uv, None).map_err(|err| {
-            self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
+            match err {
+                ErrorHandled::Reported(_) => {
+                    self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
+                }
+                ErrorHandled::TooGeneric => {
+                    span_bug!(constant.span, "codegen encountered polymorphic constant: {:?}", err);
+                }
+            }
             err
         })
     }