AMDGPU: Preserve m0 value when spilling

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@287844 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AMDGPU/SIRegisterInfo.cpp b/lib/Target/AMDGPU/SIRegisterInfo.cpp
index 93c2060381d4d9fa44ef72641594d87934c70e34..64abfef007df082e290780b58cd47ce7d467fdfa 100644 (file)
--- a/lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ b/lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -530,6 +530,16 @@ void SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI,
   assert(SuperReg != AMDGPU::M0 && "m0 should never spill");
 
   const unsigned EltSize = 4;
+  unsigned OffsetReg = AMDGPU::M0;
+  unsigned M0CopyReg = AMDGPU::NoRegister;
+
+  if (SpillToSMEM) {
+    if (RS->isRegUsed(AMDGPU::M0)) {
+      M0CopyReg = MRI.createVirtualRegister(&AMDGPU::SReg_32_XM0RegClass);
+      BuildMI(*MBB, MI, DL, TII->get(AMDGPU::COPY), M0CopyReg)
+        .addReg(AMDGPU::M0);
+    }
+  }
 
   // SubReg carries the "Kill" flag when SubReg == SuperReg.
   unsigned SubKillState = getKillRegState((NumSubRegs == 1) && IsKill);
@@ -546,7 +556,6 @@ void SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI,
         = MF->getMachineMemOperand(PtrInfo, MachineMemOperand::MOStore,
                                    EltSize, MinAlign(Align, EltSize * i));
 
-      unsigned OffsetReg = AMDGPU::M0;
       // Add i * 4 wave offset.
       //
       // SMEM instructions only support a single offset, so increment the wave
@@ -565,7 +574,7 @@ void SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI,
       BuildMI(*MBB, MI, DL, TII->get(AMDGPU::S_BUFFER_STORE_DWORD_SGPR))
         .addReg(SubReg, getKillRegState(IsKill)) // sdata
         .addReg(MFI->getScratchRSrcReg())        // sbase
-        .addReg(OffsetReg)                       // soff
+        .addReg(OffsetReg, RegState::Kill)       // soff
         .addImm(0)                               // glc
         .addMemOperand(MMO);
 
@@ -621,6 +630,11 @@ void SIRegisterInfo::spillSGPR(MachineBasicBlock::iterator MI,
     }
   }
 
+  if (M0CopyReg != AMDGPU::NoRegister) {
+    BuildMI(*MBB, MI, DL, TII->get(AMDGPU::COPY), AMDGPU::M0)
+      .addReg(M0CopyReg, RegState::Kill);
+  }
+
   MI->eraseFromParent();
   MFI->addToSpilledSGPRs(NumSubRegs);
 }
@@ -643,6 +657,18 @@ void SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
 
   assert(SuperReg != AMDGPU::M0 && "m0 should never spill");
 
+  unsigned OffsetReg = AMDGPU::M0;
+  unsigned M0CopyReg = AMDGPU::NoRegister;
+
+  if (SpillToSMEM) {
+    if (RS->isRegUsed(AMDGPU::M0)) {
+      M0CopyReg = MRI.createVirtualRegister(&AMDGPU::SReg_32_XM0RegClass);
+      BuildMI(*MBB, MI, DL, TII->get(AMDGPU::COPY), M0CopyReg)
+        .addReg(AMDGPU::M0);
+    }
+  }
+
+  // SubReg carries the "Kill" flag when SubReg == SuperReg.
   int64_t FrOffset = FrameInfo.getObjectOffset(Index);
 
   const unsigned EltSize = 4;
@@ -659,8 +685,6 @@ void SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
         = MF->getMachineMemOperand(PtrInfo, MachineMemOperand::MOLoad,
                                    EltSize, MinAlign(Align, EltSize * i));
 
-      unsigned OffsetReg = AMDGPU::M0;
-
       // Add i * 4 offset
       int64_t Offset = ST.getWavefrontSize() * (FrOffset + 4 * i);
       if (Offset != 0) {
@@ -675,7 +699,7 @@ void SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
       auto MIB =
         BuildMI(*MBB, MI, DL, TII->get(AMDGPU::S_BUFFER_LOAD_DWORD_SGPR), SubReg)
         .addReg(MFI->getScratchRSrcReg()) // sbase
-        .addReg(OffsetReg)                // soff
+        .addReg(OffsetReg, RegState::Kill)                // soff
         .addImm(0)                        // glc
         .addMemOperand(MMO);
 
@@ -726,6 +750,11 @@ void SIRegisterInfo::restoreSGPR(MachineBasicBlock::iterator MI,
     }
   }
 
+  if (M0CopyReg != AMDGPU::NoRegister) {
+    BuildMI(*MBB, MI, DL, TII->get(AMDGPU::COPY), AMDGPU::M0)
+      .addReg(M0CopyReg, RegState::Kill);
+  }
+
   MI->eraseFromParent();
 }
 

diff --git a/test/CodeGen/AMDGPU/spill-m0.ll b/test/CodeGen/AMDGPU/spill-m0.ll
index 548735f1e78a0ec9b44e46135cffb1375cc81cb0..ae3b2de30a663a5113335c5460183906b9b4a0c5 100644 (file)
--- a/test/CodeGen/AMDGPU/spill-m0.ll
+++ b/test/CodeGen/AMDGPU/spill-m0.ll
@@ -61,6 +61,30 @@ endif:
 @lds = internal addrspace(3) global [64 x float] undef
 
 ; GCN-LABEL: {{^}}spill_m0_lds:
+; GCN: s_mov_b32 m0, s6
+; GCN: v_interp_mov_f32
+
+; TOSMEM: s_mov_b32 vcc_hi, m0
+; TOSMEM: s_mov_b32 m0, s7
+; TOSMEM-NEXT: s_buffer_store_dword s{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, m0 ; 4-byte Folded Spill
+; TOSMEM: s_mov_b32 m0, vcc_hi
+
+; TOSMEM: s_mov_b32 vcc_hi, m0
+; TOSMEM: s_add_u32 m0, s7, 0x100
+; TOSMEM: s_buffer_store_dword s{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, m0 ; 4-byte Folded Spill
+; TOSMEM: s_add_u32 m0, s7, 0x200
+; TOSMEM: s_buffer_store_dword s{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, m0 ; 4-byte Folded Spill
+; TOSMEM: s_mov_b32 m0, vcc_hi
+
+; TOSMEM: s_mov_b64 exec,
+; TOSMEM: s_cbranch_execz
+; TOSMEM: s_branch
+
+; TOSMEM: BB{{[0-9]+_[0-9]+}}:
+; TOSMEM-NEXT: s_add_u32 m0, s7, 0x100
+; TOSMEM-NEXT: s_buffer_load_dword s{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, m0 ; 4-byte Folded Reload
+
+
 ; GCN-NOT: v_readlane_b32 m0
 ; GCN-NOT: s_buffer_store_dword m0
 ; GCN-NOT: s_buffer_load_dword m0
@@ -87,6 +111,52 @@ endif:
   ret void
 }
 
+; GCN-LABEL: {{^}}restore_m0_lds:
+; TOSMEM: s_cmp_eq_u32
+; TOSMEM: s_mov_b32 vcc_hi, m0
+; TOSMEM: s_mov_b32 m0, s3
+; TOSMEM: s_buffer_store_dword s4, s[84:87], m0 ; 4-byte Folded Spill
+; TOSMEM: s_mov_b32 m0, vcc_hi
+; TOSMEM: s_cbranch_scc1
+
+; TOSMEM: s_mov_b32 m0, -1
+
+; TOSMEM: s_mov_b32 vcc_hi, m0
+; TOSMEM: s_mov_b32 m0, s3
+; TOSMEM: s_buffer_load_dword s4, s[84:87], m0 ; 4-byte Folded Reload
+; TOSMEM: s_add_u32 m0, s3, 0x100
+; TOSMEM: s_waitcnt lgkmcnt(0)
+; TOSMEM: s_buffer_load_dword s5, s[84:87], m0 ; 4-byte Folded Reload
+; TOSMEM: s_mov_b32 m0, vcc_hi
+; TOSMEM: s_waitcnt lgkmcnt(0)
+
+; TOSMEM: ds_write_b64
+
+; TOSMEM: s_mov_b32 vcc_hi, m0
+; TOSMEM: s_add_u32 m0, s3, 0x200
+; TOSMEM: s_buffer_load_dword s0, s[84:87], m0 ; 4-byte Folded Reload
+; TOSMEM: s_mov_b32 m0, vcc_hi
+; TOSMEM: s_waitcnt lgkmcnt(0)
+; TOSMEM: s_mov_b32 m0, s0
+; TOSMEM: ; use m0
+
+; TOSMEM: s_dcache_wb
+; TOSMEM: s_endpgm
+define void @restore_m0_lds(i32 %arg) {
+  %m0 = call i32 asm sideeffect "s_mov_b32 m0, 0", "={M0}"() #0
+  %sval = load volatile i64, i64 addrspace(2)* undef
+  %cmp = icmp eq i32 %arg, 0
+  br i1 %cmp, label %ret, label %bb
+
+bb:
+  store volatile i64 %sval, i64 addrspace(3)* undef
+  call void asm sideeffect "; use $0", "{M0}"(i32 %m0) #0
+  br label %ret
+
+ret:
+  ret void
+}
+
 declare float @llvm.SI.fs.constant(i32, i32, i32) readnone
 
 declare i32 @llvm.SI.packf16(float, float) readnone