From a20afbefe0d65ae140069c2996f530ed1452e95d Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Sat, 18 Feb 2017 10:22:00 -0800
Subject: [PATCH] Improve assertion text for missing live ranges.

---
 lib/cretonne/src/regalloc/live_value_tracker.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/cretonne/src/regalloc/live_value_tracker.rs b/lib/cretonne/src/regalloc/live_value_tracker.rs
index 838c5b6bb9..bcbbb62fe1 100644
--- a/lib/cretonne/src/regalloc/live_value_tracker.rs
+++ b/lib/cretonne/src/regalloc/live_value_tracker.rs
@@ -229,7 +229,10 @@ impl LiveValueTracker {
         // Add the values defined by `inst`.
         let first_def = self.live.values.len();
         for value in dfg.inst_results(inst) {
-            let lr = liveness.get(value).expect("Instruction result has no live range");
+            let lr = match liveness.get(value) {
+                Some(lr) => lr,
+                None => panic!("{} result {} has no live range", dfg[inst].opcode(), value),
+            };
             assert_eq!(lr.def(), inst.into());
             match lr.def_local_end().into() {
                 ExpandedProgramPoint::Inst(endpoint) => {