From: Ben.Lippmeier@anu.edu.au <unknown>
Date: Sat, 10 Jan 2009 02:58:02 +0000 (+0000)
Subject: Better panic message in RegAllocLinear
X-Git-Url: http://git.megacz.com/?a=commitdiff_plain;h=8c4b04006dcf5aedfb11fcbc7fcfb05c2b387f92;p=ghc-hetmet.git

Better panic message in RegAllocLinear
---

diff --git a/compiler/nativeGen/RegAllocLinear.hs b/compiler/nativeGen/RegAllocLinear.hs
index c67ce3e..c4a5a4a 100644
--- a/compiler/nativeGen/RegAllocLinear.hs
+++ b/compiler/nativeGen/RegAllocLinear.hs
@@ -699,8 +699,11 @@ allocateRegsAndSpill reading keep spills alloc (r:rs) = do
 	        -- to spill.  We just pick the first one that isn't used in 
 	        -- the current instruction for now.
 
-	        let (temp_to_push_out, my_reg) = myHead "regalloc" candidates2
-
+	        let (temp_to_push_out, my_reg) 
+			= case candidates2 of
+				[]	-> panic "RegAllocLinear.allocRegsAndSpill: no spill candidates"
+				(x:_)	-> x
+				
     	        (spill_insn, slot) <- spillR (RealReg my_reg) temp_to_push_out
 		let spill_store	 = (if reading then id else reverse)
 					[ COMMENT (fsLit "spill alloc") 
@@ -741,9 +744,6 @@ loadTemp _ _ _ _ spills =
    return spills
 
 
-myHead s [] = panic s
-myHead _ (x:_) = x
-
 -- -----------------------------------------------------------------------------
 -- Joining a jump instruction to its targets