From d734f64cc5b4e8b906f0d4f1b28f67c492a05bae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= <bjorn@erlang.org>
Date: Thu, 11 Nov 2010 12:18:50 +0100
Subject: Eliminate redundant jump instructions

---
 erts/emulator/beam/beam_load.c | 8 ++++++++
 erts/emulator/beam/ops.tab     | 5 +++++
 2 files changed, 13 insertions(+)

diff --git a/erts/emulator/beam/beam_load.c b/erts/emulator/beam/beam_load.c
index cf87e111db..65cd6f91bb 100644
--- a/erts/emulator/beam/beam_load.c
+++ b/erts/emulator/beam/beam_load.c
@@ -2260,6 +2260,14 @@ mixed_types(LoaderState* stp, GenOpArg Size, GenOpArg* Rest)
     return 0;
 }
 
+static int
+same_label(LoaderState* stp, GenOpArg Target, GenOpArg Label)
+{
+    return Target.type = TAG_f && Label.type == TAG_u &&
+	Target.val == Label.val;
+}
+
+
 /*
  * Generate an instruction for element/2.
  */
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index 2d89926bc5..81be97fd1e 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -163,6 +163,11 @@ i_select_tuple_arity s f I
 i_jump_on_val_zero s f I
 i_jump_on_val s f I I
 
+jump Target | label Lbl | same_label(Target, Lbl) => label Lbl
+
+is_ne_exact L1 S1 S2 | jump Fail | label L2 | same_label(L1, L2) => \
+  is_eq_exact Fail S1 S2 | label L2
+
 %macro: get_list GetList -pack
 get_list x x x
 get_list x x y
-- 
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