From d8eaa19ddafbe8bfbbbe583b49809a67e6cbc4fb Mon Sep 17 00:00:00 2001
From: Dan Gohman <sunfish@mozilla.com>
Date: Tue, 29 May 2018 14:11:07 -0700
Subject: [PATCH] Make an assert message more verbose.

---
 lib/codegen/src/regalloc/reload.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/codegen/src/regalloc/reload.rs b/lib/codegen/src/regalloc/reload.rs
index ff204a4fd9..b8ba2166ca 100644
--- a/lib/codegen/src/regalloc/reload.rs
+++ b/lib/codegen/src/regalloc/reload.rs
@@ -283,7 +283,11 @@ impl<'a> Context<'a> {
                 .expect("Extra results on non-call instruction");
             for (i, lv) in retvals.iter().enumerate() {
                 let abi = self.cur.func.dfg.signatures[sig].returns[i];
-                debug_assert!(abi.location.is_reg());
+                debug_assert!(
+                    abi.location.is_reg(),
+                    "expected reg; got {:?}",
+                    abi.location
+                );
                 if lv.affinity.is_stack() {
                     let reg = self.cur.func.dfg.replace_result(lv.value, abi.value_type);
                     self.liveness