minor cleanup

Author: xacrimon

Cargo.toml

@@ -95,6 +95,6 @@ codegen-units = 1
 # lto = true
 
 [profile.release.package.rustc_mir_build]
-opt-level = 1
+opt-level = 0
 [profile.release.package.rustc_driver]
-opt-level = 1
+opt-level = 0

compiler/rustc_mir_build/src/builder/matches/match_pair.rs

@@ -56,9 +56,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             ((prefix.len() + suffix.len()).try_into().unwrap(), false)
         };
 
-        let mut prefix_opt = false;
-
-        if self.is_constant_pattern_subslice(prefix) && opt_slice.is_none() && suffix.len() == 0 {
+        if self.subslice_work_optimizing(prefix) {
             let elem_ty = prefix[0].ty;
             let prefix_valtree = self.simplify_const_pattern_slice_into_valtree(prefix);
 
@@ -72,10 +70,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             );
 
             match_pairs.push(match_pair);
-            prefix_opt = true;
-        }
-
-        if !prefix_opt {
+        } else {
             match_pairs.extend(prefix.iter().enumerate().map(|(idx, subpattern)| {
                 let elem = ProjectionElem::ConstantIndex {
                     offset: idx as u64,
@@ -108,17 +103,16 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         }));
     }
 
-    fn is_constant_pattern_subslice(&self, subslice: &[Box<Pat<'tcx>>]) -> bool {
-        subslice.len() > 1 && subslice.iter().all(|p| self.is_constant_pattern(p))
+    fn subslice_work_optimizing(&self, subslice: &[Box<Pat<'tcx>>]) -> bool {
+        slice.len() > 1 && subslice.iter().all(|p| self.is_constant_pattern(p))
     }
 
     fn is_constant_pattern(&self, pat: &Pat<'tcx>) -> bool {
         if let PatKind::Constant { value } = pat.kind
             && let Const::Ty(_, const_) = value
             && let ty::ConstKind::Value(ty, valtree) = const_.kind()
-            && let ty::ValTree::Leaf(scalar) = valtree
+            && let ty::ValTree::Leaf(_) = valtree
             && self.tcx.types.u8 == ty
-            && scalar.to_u8() != b'_'
         {
             true
         } else {