[AMDGPU] Avoid offset register in MUBUF for direct stack object accesses

We use an absolute address for stack objects and
it would be necessary to have a constant 0 for soffset field.

Fixes: SWDEV-228562

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D89234

diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
index 8915ef8..8993d41 100644 (file)
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelDAGToDAG.cpp
@@ -1468,22 +1468,14 @@ static bool isStackPtrRelative(const MachinePointerInfo &PtrInfo) {
 
 std::pair<SDValue, SDValue> AMDGPUDAGToDAGISel::foldFrameIndex(SDValue N) const {
   SDLoc DL(N);
-  const MachineFunction &MF = CurDAG->getMachineFunction();
-  const SIMachineFunctionInfo *Info = MF.getInfo<SIMachineFunctionInfo>();
 
-  if (auto FI = dyn_cast<FrameIndexSDNode>(N)) {
-    SDValue TFI = CurDAG->getTargetFrameIndex(FI->getIndex(),
-                                              FI->getValueType(0));
-
-    // If we can resolve this to a frame index access, this will be relative to
-    // either the stack or frame pointer SGPR.
-    return std::make_pair(
-        TFI, CurDAG->getRegister(Info->getStackPtrOffsetReg(), MVT::i32));
-  }
+  auto *FI = dyn_cast<FrameIndexSDNode>(N);
+  SDValue TFI =
+      FI ? CurDAG->getTargetFrameIndex(FI->getIndex(), FI->getValueType(0)) : N;
 
-  // If we don't know this private access is a local stack object, it needs to
-  // be relative to the entry point's scratch wave offset.
-  return std::make_pair(N, CurDAG->getTargetConstant(0, DL, MVT::i32));
+  // We rebase the base address into an absolute stack address and hence
+  // use constant 0 for soffset.
+  return std::make_pair(TFI, CurDAG->getTargetConstant(0, DL, MVT::i32));
 }
 
 bool AMDGPUDAGToDAGISel::SelectMUBUFScratchOffen(SDNode *Parent,

diff --git a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
index a4e9444..e064197 100644 (file)
--- a/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIRegisterInfo.cpp
@@ -478,9 +478,10 @@ void SIRegisterInfo::resolveFrameIndex(MachineInstr &MI, Register BaseReg,
   assert(TII->isMUBUF(MI));
 
   MachineOperand *SOffset = TII->getNamedOperand(MI, AMDGPU::OpName::soffset);
-  assert(SOffset->getReg() ==
-             MF->getInfo<SIMachineFunctionInfo>()->getStackPtrOffsetReg() &&
-         "should only be seeing stack pointer offset relative FrameIndex");
+  assert((SOffset->isReg() &&
+          SOffset->getReg() ==
+              MF->getInfo<SIMachineFunctionInfo>()->getStackPtrOffsetReg()) ||
+         (SOffset->isImm() && SOffset->getImm() == 0));
 
   MachineOperand *OffsetOp = TII->getNamedOperand(MI, AMDGPU::OpName::offset);
   int64_t NewOffset = OffsetOp->getImm() + Offset;
@@ -489,10 +490,6 @@ void SIRegisterInfo::resolveFrameIndex(MachineInstr &MI, Register BaseReg,
 
   FIOp->ChangeToRegister(BaseReg, false);
   OffsetOp->setImm(NewOffset);
-
-  // The move materializing the base address will be an absolute stack address,
-  // so clear the base offset.
-  SOffset->ChangeToImmediate(0);
 }
 
 bool SIRegisterInfo::isFrameOffsetLegal(const MachineInstr *MI,
@@ -1455,6 +1452,8 @@ void SIRegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator MI,
           } else {
             SOffset.setReg(FrameReg);
           }
+        } else if (SOffset.isImm() && FrameReg != AMDGPU::NoRegister) {
+          SOffset.ChangeToRegister(FrameReg, false);
         }
 
         int64_t Offset = FrameInfo.getObjectOffset(Index);

diff --git a/llvm/test/CodeGen/AMDGPU/call-argument-types.ll b/llvm/test/CodeGen/AMDGPU/call-argument-types.ll
index fb1cd3b..20d398c 100644 (file)
--- a/llvm/test/CodeGen/AMDGPU/call-argument-types.ll
+++ b/llvm/test/CodeGen/AMDGPU/call-argument-types.ll
@@ -744,13 +744,13 @@ entry:
 
 ; GCN-LABEL: {{^}}tail_call_byval_align16:
 ; GCN-NOT: s32
-; GCN: buffer_load_dword v32, off, s[0:3], s32 offset:12
-; GCN: buffer_load_dword v33, off, s[0:3], s32 offset:8
+; GCN: buffer_load_dword [[VREG1:v[0-9]+]], off, s[0:3], s32 offset:8
+; GCN: buffer_load_dword [[VREG2:v[0-9]+]], off, s[0:3], s32 offset:12
 
 ; GCN: s_getpc_b64
 
-; GCN: buffer_store_dword v32, off, s[0:3], s32 offset:4
-; GCN: buffer_store_dword v33, off, s[0:3], s32{{$}}
+; GCN: buffer_store_dword [[VREG2]], off, s[0:3], s32 offset:4
+; GCN: buffer_store_dword [[VREG1]], off, s[0:3], s32{{$}}
 ; GCN-NOT: s32
 ; GCN: s_setpc_b64
 define void @tail_call_byval_align16(<32 x i32> %val, double %tmp) #0 {

diff --git a/llvm/test/CodeGen/AMDGPU/callee-special-input-vgprs.ll b/llvm/test/CodeGen/AMDGPU/callee-special-input-vgprs.ll
index 9bbcc23..18fe484 100644 (file)
--- a/llvm/test/CodeGen/AMDGPU/callee-special-input-vgprs.ll
+++ b/llvm/test/CodeGen/AMDGPU/callee-special-input-vgprs.ll
@@ -611,12 +611,10 @@ define void @too_many_args_use_workitem_id_x_byval(
 ; GCN-LABEL: {{^}}kern_call_too_many_args_use_workitem_id_x_byval:
 ; VARABI: enable_vgpr_workitem_id = 0
 ; VARABI: v_mov_b32_e32 [[K:v[0-9]+]], 0x3e7{{$}}
-; VARABI: buffer_store_dword [[K]], off, s[0:3], 0 offset:4
-; VARABI: buffer_load_dword [[RELOAD_BYVAL:v[0-9]+]], off, s[0:3], 0 offset:4
 ; VARABI: s_movk_i32 s32, 0x400{{$}}
-
-; VARABI-NOT: s32
+; VARABI: buffer_store_dword [[K]], off, s[0:3], 0 offset:4
 ; VARABI: buffer_store_dword v0, off, s[0:3], s32 offset:4
+; VARABI: buffer_load_dword [[RELOAD_BYVAL:v[0-9]+]], off, s[0:3], 0 offset:4
 
 ; VARABI: buffer_store_dword [[RELOAD_BYVAL]], off, s[0:3], s32{{$}}
 ; VARABI: v_mov_b32_e32 [[RELOAD_BYVAL]],
@@ -660,8 +658,8 @@ define amdgpu_kernel void @kern_call_too_many_args_use_workitem_id_x_byval() #1
 ; GCN-LABEL: {{^}}func_call_too_many_args_use_workitem_id_x_byval:
 ; VARABI: v_mov_b32_e32 [[K:v[0-9]+]], 0x3e7{{$}}
 ; VARABI: buffer_store_dword [[K]], off, s[0:3], s33{{$}}
-; VARABI: buffer_load_dword [[RELOAD_BYVAL:v[0-9]+]], off, s[0:3], s33{{$}}
 ; VARABI: buffer_store_dword v0, off, s[0:3], s32 offset:4
+; VARABI: buffer_load_dword [[RELOAD_BYVAL:v[0-9]+]], off, s[0:3], s33{{$}}
 ; VARABI: buffer_store_dword [[RELOAD_BYVAL]], off, s[0:3], s32{{$}}
 ; VARABI: v_mov_b32_e32 [[RELOAD_BYVAL]],
 ; VARABI: s_swappc_b64