From 1adc9a307ca9009a9cd39b7ed109cd9ecb597200 Mon Sep 17 00:00:00 2001
From: Kaz Kylheku <kaz@kylheku.com>
Date: Tue, 21 Mar 2023 20:51:13 -0700
Subject: compiler: bug: unmatchable pattern in optimizer.

This was uncovered by unused variable warnings.

* stdlib/optimize.tl (basic-blocks peephole-block):
The pattern trying to detect wasteful register moves
is incorrect; the reg1 term is intended to be the
@reg1 variable. It is matched literally and so will
not match because the symbol reg1 does not literally
occur in the VM code.
---
 stdlib/optimize.tl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/stdlib/optimize.tl b/stdlib/optimize.tl
index 329bae03..7681bca1 100644
--- a/stdlib/optimize.tl
+++ b/stdlib/optimize.tl
@@ -397,7 +397,7 @@
       ;; wasteful moves
       (((mov @reg0 @nil) (mov @reg0 @nil) . @nil)
        (cdr insns))
-      (((mov @reg0 @reg1) (mov reg1 @reg0) . @rest)
+      (((mov @reg0 @reg1) (mov @reg1 @reg0) . @rest)
        (pushnew bl bb.rescan)
        (set bb.recalc t)
        ^(,(car insns) ,*rest))
-- 
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