1 files changed, 24 insertions, 9 deletions

diff --git a/gcc/rust/backend/rust-compile-pattern.cc b/gcc/rust/backend/rust-compile-pattern.cc
index 27ee487..ffda652 100644
--- a/gcc/rust/backend/rust-compile-pattern.cc
+++ b/gcc/rust/backend/rust-compile-pattern.cc
@@ -17,6 +17,8 @@
 // <http://www.gnu.org/licenses/>.
 
 #include "rust-compile-pattern.h"
+#include "rust-compile-expr.h"
+#include "rust-constexpr.h"
 
 namespace Rust {
 namespace Compile {
@@ -46,20 +48,33 @@ CompilePatternCaseLabelExpr::visit (HIR::PathInExpression &pattern)
   ok = adt->lookup_variant_by_id (variant_id, &variant);
   rust_assert (ok);
 
-  mpz_t disciminantl;
-  if (variant->get_variant_type () == TyTy::VariantDef::VariantType::NUM)
+  tree case_low = error_mark_node;
+  if (variant->is_specified_discriminant_node ())
     {
-      mpz_init_set_ui (disciminantl, variant->get_discriminant ());
+      auto discrim_node = variant->get_discriminant_node ();
+      auto &discrim_expr = discrim_node->get_discriminant_expression ();
+
+      tree discrim_expr_node = CompileExpr::Compile (discrim_expr.get (), ctx);
+      tree folded_discrim_expr = ConstCtx::fold (discrim_expr_node);
+      case_low = folded_discrim_expr;
     }
   else
     {
-      HirId variant_id = variant->get_id ();
-      mpz_init_set_ui (disciminantl, variant_id);
-    }
+      mpz_t disciminantl;
+      if (variant->get_variant_type () == TyTy::VariantDef::VariantType::NUM)
+	{
+	  mpz_init_set_ui (disciminantl, variant->get_discriminant ());
+	}
+      else
+	{
+	  HirId variant_id = variant->get_id ();
+	  mpz_init_set_ui (disciminantl, variant_id);
+	}
 
-  tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
-  tree case_low
-    = double_int_to_tree (t, mpz_get_double_int (t, disciminantl, true));
+      tree t = TyTyResolveCompile::get_implicit_enumeral_node_type (ctx);
+      case_low
+	= double_int_to_tree (t, mpz_get_double_int (t, disciminantl, true));
+    }
 
   case_label_expr
     = build_case_label (case_low, NULL_TREE, associated_case_label);