From a69b85acbf5f81a1a684156e152e68aa2ae40e99 Mon Sep 17 00:00:00 2001
From: Camil Staps
Date: Fri, 28 Jul 2017 11:05:15 +0200
Subject: Optimise: remove unreachacble ABC-code

---
 Sil/Compile.icl | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'Sil/Compile.icl')

diff --git a/Sil/Compile.icl b/Sil/Compile.icl
index 81196bf..e342a66 100644
--- a/Sil/Compile.icl
+++ b/Sil/Compile.icl
@@ -47,6 +47,8 @@ where
 	opt ['ABC'.PushI i:'ABC'.Update_b 0 l:'ABC'.Pop_b n:ss] | l == n = ['ABC'.Pop_b n:'ABC'.PushI i:opt ss]
 	opt ['ABC'.Pop_a i:'ABC'.Pop_a j:ss] = opt ['ABC'.Pop_a (i+j):ss]
 	opt ['ABC'.Pop_b i:'ABC'.Pop_b j:ss] = opt ['ABC'.Pop_b (i+j):ss]
+	opt ['ABC'.Rtn:ss] = ['ABC'.Rtn:opt $ skipUntilEntryPoint ss]
+	opt ['ABC'.Jmp l:ss] = ['ABC'.Jmp l:opt $ skipUntilEntryPoint ss]
 	opt [s:ss] = [s:opt ss]
 	opt []     = []
 
@@ -58,6 +60,14 @@ where
 	isUseful ('ABC'.Comment _)    = False
 	isUseful _                    = True
 
+	skipUntilEntryPoint :: 'ABC'.Assembler -> 'ABC'.Assembler
+	skipUntilEntryPoint ss
+	| all (\t -> t =: ('ABC'.Annotation _)) before = ss
+	| otherwise                                    = skipUntilEntryPoint $ tl ss
+	where
+		(before,after) = span (not o (\t -> t =: ('ABC'.Label _))) ss
+	skipUntilEntryPoint [] = []
+
 :: Address
 	= AAddr Int
 	| BAddr Int
-- 
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