From 88b79b875731199a789bbda43d104ea9c8a1f235 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Wed, 15 Apr 2015 15:43:51 +0200
Subject: erts: Optimize comparison operator for frequent immediates

* small integers
* atoms
---
 erts/emulator/beam/utils.c | 33 +++++++++++++++++++++++++++++++--
 1 file changed, 31 insertions(+), 2 deletions(-)

(limited to 'erts')

diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c
index aecfe04a75..4db2015eea 100644
--- a/erts/emulator/beam/utils.c
+++ b/erts/emulator/beam/utils.c
@@ -2922,15 +2922,44 @@ Sint cmp(Eterm a, Eterm b)
 }
 #endif
 
+#if HALFWORD_HEAP
+static Sint erts_cmp_compound_rel_opt(Eterm a, Eterm* a_base,
+                                     Eterm b, Eterm* b_base,
+                                     int exact, int eq_only);
+#else
+static Sint erts_cmp_compound(Eterm a, Eterm b, int exact, int eq_only);
+#endif
+
+#if HALFWORD_HEAP
+Sint erts_cmp(Eterm a, Eterm* a_base,
+              Eterm b, Eterm* b_base,
+              int exact, int eq_only)
+#else
+Sint erts_cmp(Eterm a, Eterm b, int exact, int eq_only)
+#endif
+{
+    if (is_atom(a) && is_atom(b)) {
+        return cmp_atoms(a, b);
+    } else if (is_both_small(a, b)) {
+        return (signed_val(a) - signed_val(b));
+    }
+#if HALFWORD_HEAP
+    return erts_cmp_compound(a,a_base,b,b_base,exact,eq_only);
+#else
+    return erts_cmp_compound(a,b,exact,eq_only);
+#endif
+}
+
+
 /* erts_cmp(Eterm a, Eterm b, int exact)
  * exact = 1 -> term-based compare
  * exact = 0 -> arith-based compare
  */
 #if HALFWORD_HEAP
-Sint erts_cmp_rel_opt(Eterm a, Eterm* a_base, Eterm b, Eterm* b_base,
+static Sint erts_cmp_compound_rel_opt(Eterm a, Eterm* a_base, Eterm b, Eterm* b_base,
                       int exact, int eq_only)
 #else
-Sint erts_cmp(Eterm a, Eterm b, int exact, int eq_only)
+static Sint erts_cmp_compound(Eterm a, Eterm b, int exact, int eq_only)
 #endif
 {
 #define PSTACK_TYPE struct erts_cmp_hashmap_state
-- 
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