From: Tom Stellard <thomas.stellard@amd.com>
Date: Mon, 2 May 2016 19:37:56 +0000 (+0000)
Subject: AMDGPU/SI: Set the kill flag on temp VGPRs used to restore SGPRs from scratch
X-Git-Tag: llvmorg-3.9.0-rc1~7227
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ce5e994887f7700da3b22bd1b027f52092e5cabb;p=platform%2Fupstream%2Fllvm.git

AMDGPU/SI: Set the kill flag on temp VGPRs used to restore SGPRs from scratch

Summary:
When we restore an SGPR value from scratch, we first load it into a
temporary VGPR and then use v_readlane_b32 to copy the value from the
VGPR back into an SGPR.

We weren't setting the kill flag on the VGPR in the v_readlane_b32
instruction, so the register scavenger wasn't able to re-use this
temp value later.

I wasn't able to create a lit test for this.

Reviewers: arsenm

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D19744

llvm-svn: 268287
---

diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
index d0ba8e6..9012b31 100644
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -590,7 +590,7 @@ void SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
                   .addMemOperand(MMO);
           BuildMI(*MBB, MI, DL,
                   TII->getMCOpcodeFromPseudo(AMDGPU::V_READLANE_B32), SubReg)
-                  .addReg(TmpReg)
+                  .addReg(TmpReg, RegState::Kill)
                   .addImm(0)
                   .addReg(MI->getOperand(0).getReg(), RegState::ImplicitDefine);
         }