# HG changeset patch
# User adinn
# Date 1534950411 -3600
# Node ID 25048be67f4a966f34a6a3c744f65d8ed0d5a087
# Parent  b5abbca5b2dc99c08b04ca95bfa67075e832bfa7
8209783: AArch64: Combine Multiply and Neg operations in C2
Summary: Generate mneg instructions for a*(-b) or (-a)*b to save one instruction
Reviewed-by: adinn
Contributed-by: pengfei.li@arm.com

diff -r b5abbca5b2dc -r 25048be67f4a src/hotspot/cpu/aarch64/aarch64.ad
--- a/src/hotspot/cpu/aarch64/aarch64.ad	Wed Aug 22 10:36:39 2018 +0200
+++ b/src/hotspot/cpu/aarch64/aarch64.ad	Wed Aug 22 16:06:51 2018 +0100
@@ -9623,6 +9623,24 @@
   ins_pipe(imac_reg_reg);
 %}
 
+// Combined Integer Multiply & Neg
+
+instruct mnegI(iRegINoSp dst, iRegIorL2I src1, iRegIorL2I src2, immI0 zero) %{
+  match(Set dst (MulI (SubI zero src1) src2));
+  match(Set dst (MulI src1 (SubI zero src2)));
+
+  ins_cost(INSN_COST * 3);
+  format %{ "mneg  $dst, $src1, $src2" %}
+
+  ins_encode %{
+    __ mnegw(as_Register($dst$$reg),
+             as_Register($src1$$reg),
+             as_Register($src2$$reg));
+  %}
+
+  ins_pipe(imac_reg_reg);
+%}
+
 // Combined Long Multiply & Add/Sub
 
 instruct maddL(iRegLNoSp dst, iRegL src1, iRegL src2, iRegL src3) %{
@@ -9657,6 +9675,24 @@
   ins_pipe(lmac_reg_reg);
 %}
 
+// Combined Long Multiply & Neg
+
+instruct mnegL(iRegLNoSp dst, iRegL src1, iRegL src2, immL0 zero) %{
+  match(Set dst (MulL (SubL zero src1) src2));
+  match(Set dst (MulL src1 (SubL zero src2)));
+
+  ins_cost(INSN_COST * 5);
+  format %{ "mneg  $dst, $src1, $src2" %}
+
+  ins_encode %{
+    __ mneg(as_Register($dst$$reg),
+            as_Register($src1$$reg),
+            as_Register($src2$$reg));
+  %}
+
+  ins_pipe(lmac_reg_reg);
+%}
+
 // Integer Divide
 
 instruct divI(iRegINoSp dst, iRegIorL2I src1, iRegIorL2I src2) %{