From 8ffc5ca5320db705acbb6f2e42660118c3ff4390 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Tue, 31 Mar 2015 02:49:58 +0000
Subject: [PATCH] [bpf] mark mov instructions as ReMaterializable

loading immediate into register is cheap, so take advantage of remat.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233666 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/BPF/BPFInstrInfo.td | 7 +++++--
 test/CodeGen/BPF/basictest.ll  | 4 ++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/lib/Target/BPF/BPFInstrInfo.td b/lib/Target/BPF/BPFInstrInfo.td
index 346c7f9b787..26b2cfebdc8 100644
--- a/lib/Target/BPF/BPFInstrInfo.td
+++ b/lib/Target/BPF/BPFInstrInfo.td
@@ -231,8 +231,6 @@ class MOV_RI<string OpcodeStr>
   let BPFSrc = 0;   // BPF_K
   let BPFClass = 7; // BPF_ALU64
 }
-def MOV_rr : MOV_RR<"mov">;
-def MOV_ri : MOV_RI<"mov">;
 
 class LD_IMM64<bits<4> Pseudo, string OpcodeStr>
     : InstBPF<(outs GPR:$dst), (ins u64imm:$imm),
@@ -255,7 +253,12 @@ class LD_IMM64<bits<4> Pseudo, string OpcodeStr>
   let size = 3;     // BPF_DW
   let BPFClass = 0; // BPF_LD
 }
+
+let isReMaterializable = 1, isAsCheapAsAMove = 1 in {
 def LD_imm64 : LD_IMM64<0, "ld_64">;
+def MOV_rr : MOV_RR<"mov">;
+def MOV_ri : MOV_RI<"mov">;
+}
 
 def LD_pseudo
     : InstBPF<(outs GPR:$dst), (ins i64imm:$pseudo, u64imm:$imm),
diff --git a/test/CodeGen/BPF/basictest.ll b/test/CodeGen/BPF/basictest.ll
index c0b6af414d0..2a2d49878a6 100644
--- a/test/CodeGen/BPF/basictest.ll
+++ b/test/CodeGen/BPF/basictest.ll
@@ -8,8 +8,8 @@ define i32 @test0(i32 %X) {
 }
 
 ; CHECK-LABEL: store_imm:
-; CHECK: stw  0(r1), r0
-; CHECK: stw  4(r2), r0
+; CHECK: stw  0(r1), r{{[03]}}
+; CHECK: stw  4(r2), r{{[03]}}
 define i32 @store_imm(i32* %a, i32* %b) {
 entry:
   store i32 0, i32* %a, align 4
-- 
2.34.1