From b58b4718012cfb848dad3106b2ab22c08997c639 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn-Egil=20Dahlberg?= <egil@erlang.org>
Date: Thu, 23 Apr 2015 19:21:34 +0200
Subject: erts: Specialize rem instruction for common case

* i_rem specialization on x registers
---
 erts/emulator/beam/beam_emu.c | 13 +++++++++++++
 erts/emulator/beam/ops.tab    |  2 ++
 2 files changed, 15 insertions(+)

(limited to 'erts')

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index aca340db6b..f369d7b632 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -2902,6 +2902,19 @@ do {								\
         goto lb_Cl_error;                \
     } while(0)
 
+ OpCase(i_rem_jIxxd):
+ {
+     Eterm result;
+
+     if (xb(Arg(3)) == SMALL_ZERO) {
+	 goto badarith;
+     } else if (is_both_small(xb(Arg(2)), xb(Arg(3)))) {
+	 result = make_small(signed_val(xb(Arg(2))) % signed_val(xb(Arg(3))));
+         StoreBifResult(4, result);
+     }
+     DO_BIG_ARITH(ARITH_FUNC(int_rem),xb(Arg(2)),xb(Arg(3)));
+ }
+
  OpCase(i_rem_jId):
  {
      Eterm result;
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index 3436b664d9..7f7b0baacc 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -1658,6 +1658,7 @@ gc_bif2 Fail I u$bif:erlang:stimes/2 S1 S2 Dst=d => i_fetch S1 S2 | i_times Fail
 gc_bif2 Fail I u$bif:erlang:div/2 S1 S2 Dst=d => i_fetch S1 S2 | i_m_div Fail I Dst
 
 gc_bif2 Fail I u$bif:erlang:intdiv/2 S1 S2 Dst=d => i_fetch S1 S2 | i_int_div Fail I Dst
+gc_bif2 Fail I u$bif:erlang:rem/2 S1=x S2=x Dst=d => i_rem Fail I S1 S2 Dst
 gc_bif2 Fail I u$bif:erlang:rem/2 S1 S2 Dst=d => i_fetch S1 S2 | i_rem Fail I Dst
 
 gc_bif2 Fail I u$bif:erlang:bsl/2 S1 S2 Dst=d => i_fetch S1 S2 | i_bsl Fail I Dst
@@ -1682,6 +1683,7 @@ i_minus j I d
 i_times j I d
 i_m_div j I d
 i_int_div j I d
+i_rem j I x x d
 i_rem j I d
 
 i_bsl j I d
-- 
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