8209783: AArch64: Combine Multiply and Neg operations in C2
Generate mneg instructions for a*(-b) or (-a)*b to save one instruction
Reviewed-by: adinn
diff --git a/src/hotspot/cpu/aarch64/aarch64.ad b/src/hotspot/cpu/aarch64/aarch64.ad
index d7680d1..abc26ae 100644
--- a/src/hotspot/cpu/aarch64/aarch64.ad
+++ b/src/hotspot/cpu/aarch64/aarch64.ad
@@ -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) %{
