1 files changed, 21 insertions, 10 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/mod.rs b/compiler/rustc_codegen_ssa/src/mir/mod.rs
index 3a896071bc6..0758e5d0456 100644
--- a/compiler/rustc_codegen_ssa/src/mir/mod.rs
+++ b/compiler/rustc_codegen_ssa/src/mir/mod.rs
@@ -3,7 +3,7 @@ use std::iter;
 use rustc_index::IndexVec;
 use rustc_index::bit_set::DenseBitSet;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
-use rustc_middle::mir::{UnwindTerminateReason, traversal};
+use rustc_middle::mir::{Local, UnwindTerminateReason, traversal};
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, HasTypingEnv, TyAndLayout};
 use rustc_middle::ty::{self, Instance, Ty, TyCtxt, TypeFoldable, TypeVisitableExt};
 use rustc_middle::{bug, mir, span_bug};
@@ -240,7 +240,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     let local_values = {
         let args = arg_local_refs(&mut start_bx, &mut fx, &memory_locals);
 
-        let mut allocate_local = |local| {
+        let mut allocate_local = |local: Local| {
             let decl = &mir.local_decls[local];
             let layout = start_bx.layout_of(fx.monomorphize(decl.ty));
             assert!(!layout.ty.has_erasable_regions());
@@ -502,14 +502,25 @@ fn find_cold_blocks<'tcx>(
     for (bb, bb_data) in traversal::postorder(mir) {
         let terminator = bb_data.terminator();
 
-        // If a BB ends with a call to a cold function, mark it as cold.
-        if let mir::TerminatorKind::Call { ref func, .. } = terminator.kind
-            && let ty::FnDef(def_id, ..) = *func.ty(local_decls, tcx).kind()
-            && let attrs = tcx.codegen_fn_attrs(def_id)
-            && attrs.flags.contains(CodegenFnAttrFlags::COLD)
-        {
-            cold_blocks[bb] = true;
-            continue;
+        match terminator.kind {
+            // If a BB ends with a call to a cold function, mark it as cold.
+            mir::TerminatorKind::Call { ref func, .. }
+            | mir::TerminatorKind::TailCall { ref func, .. }
+                if let ty::FnDef(def_id, ..) = *func.ty(local_decls, tcx).kind()
+                    && let attrs = tcx.codegen_fn_attrs(def_id)
+                    && attrs.flags.contains(CodegenFnAttrFlags::COLD) =>
+            {
+                cold_blocks[bb] = true;
+                continue;
+            }
+
+            // If a BB ends with an `unreachable`, also mark it as cold.
+            mir::TerminatorKind::Unreachable => {
+                cold_blocks[bb] = true;
+                continue;
+            }
+
+            _ => {}
         }
 
         // If all successors of a BB are cold and there's at least one of them, mark this BB as cold