[SPIR-V] Emit valid Lifestart/Lifestop instructions (llvm#98475)

This PR fixes emission of valid OpLifestart/OpLifestop instructions.
According to
https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#OpLifetimeStart:
"Size must be 0 if Pointer is a pointer to a non-void type or the
Addresses
[capability](https://registry.khronos.org/SPIR-V/specs/unified1/SPIRV.html#Capability)
is not declared.". The `Size` argument is set the corresponding
intrinsics arguments, so Size is not zero we must ensure that Pointer
has the required type by inserting a bitcast if needed.

Author: VyacheslavLevytskyy

llvm/lib/Target/SPIRV/SPIRVISelLowering.cpp

@@ -203,6 +203,30 @@ static void validateGroupWaitEventsPtr(const SPIRVSubtarget &STI,
   doInsertBitcast(STI, MRI, GR, I, OpReg, OpIdx, NewPtrType);
 }
 
+static void validateLifetimeStart(const SPIRVSubtarget &STI,
+                                  MachineRegisterInfo *MRI,
+                                  SPIRVGlobalRegistry &GR, MachineInstr &I) {
+  Register PtrReg = I.getOperand(0).getReg();
+  MachineFunction *MF = I.getParent()->getParent();
+  Register PtrTypeReg = getTypeReg(MRI, PtrReg);
+  SPIRVType *PtrType = GR.getSPIRVTypeForVReg(PtrTypeReg, MF);
+  SPIRVType *PonteeElemType = PtrType ? GR.getPointeeType(PtrType) : nullptr;
+  if (!PonteeElemType || PonteeElemType->getOpcode() == SPIRV::OpTypeVoid ||
+      (PonteeElemType->getOpcode() == SPIRV::OpTypeInt &&
+       PonteeElemType->getOperand(1).getImm() == 8))
+    return;
+  // To keep the code valid a bitcast must be inserted
+  SPIRV::StorageClass::StorageClass SC =
+      static_cast<SPIRV::StorageClass::StorageClass>(
+          PtrType->getOperand(1).getImm());
+  MachineIRBuilder MIB(I);
+  LLVMContext &Context = MF->getFunction().getContext();
+  SPIRVType *ElemType =
+      GR.getOrCreateSPIRVType(IntegerType::getInt8Ty(Context), MIB);
+  SPIRVType *NewPtrType = GR.getOrCreateSPIRVPointerType(ElemType, MIB, SC);
+  doInsertBitcast(STI, MRI, GR, I, PtrReg, 0, NewPtrType);
+}
+
 static void validateGroupAsyncCopyPtr(const SPIRVSubtarget &STI,
                                       MachineRegisterInfo *MRI,
                                       SPIRVGlobalRegistry &GR, MachineInstr &I,
@@ -413,6 +437,11 @@ void SPIRVTargetLowering::finalizeLowering(MachineFunction &MF) const {
                                       SPIRV::OpTypeBool))
           MI.setDesc(STI.getInstrInfo()->get(SPIRV::OpLogicalNotEqual));
         break;
+      case SPIRV::OpLifetimeStart:
+      case SPIRV::OpLifetimeStop:
+        if (MI.getOperand(1).getImm() > 0)
+          validateLifetimeStart(STI, MRI, GR, MI);
+        break;
       case SPIRV::OpGroupAsyncCopy:
         validateGroupAsyncCopyPtr(STI, MRI, GR, MI, 3);
         validateGroupAsyncCopyPtr(STI, MRI, GR, MI, 4);

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -2088,9 +2088,7 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
                                                        : SPIRV::OpLifetimeStop;
     int64_t Size = I.getOperand(I.getNumExplicitDefs() + 1).getImm();
     Register PtrReg = I.getOperand(I.getNumExplicitDefs() + 2).getReg();
-    unsigned PonteeOpType = GR.getPointeeTypeOp(PtrReg);
-    bool IsNonvoidPtr = PonteeOpType != 0 && PonteeOpType != SPIRV::OpTypeVoid;
-    if (Size == -1 || IsNonvoidPtr)
+    if (Size == -1)
       Size = 0;
     BuildMI(BB, I, I.getDebugLoc(), TII.get(Op)).addUse(PtrReg).addImm(Size);
   } break;

llvm/test/CodeGen/SPIRV/llvm-intrinsics/lifetime.ll

@@ -1,22 +1,61 @@
+; RUN: llc -O0 -mtriple=spirv64-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
 ; RUN: llc -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv32-unknown-unknown %s -o - -filetype=obj | spirv-val %}
 
-; CHECK: OpFunction
-; CHECK: %[[FooArg:.*]] = OpVariable
-; CHECK: OpLifetimeStart %[[FooArg]], 0
-; CHECK: OpCopyMemorySized
-; CHECK: OpBitcast
-; CHECK: OpInBoundsPtrAccessChain
-; CHECK: OpLifetimeStop %[[FooArg]], 0
+; CHECK-DAG: %[[#Char:]] = OpTypeInt 8 0
+; CHECK-DAG: %[[#PtrChar:]] = OpTypePointer Function %[[#Char]]
 
 %tprange = type { %tparray }
 %tparray = type { [2 x i64] }
 
+; CHECK: OpFunction
+; CHECK: %[[#FooVar:]] = OpVariable
+; CHECK: %[[#Casted1:]] = OpBitcast %[[#PtrChar]] %[[#FooVar]]
+; CHECK: OpLifetimeStart %[[#Casted1]], 72
+; CHECK: OpCopyMemorySized
+; CHECK: OpBitcast
+; CHECK: OpInBoundsPtrAccessChain
+; CHECK: %[[#Casted2:]] = OpBitcast %[[#PtrChar]] %[[#FooVar]]
+; CHECK: OpLifetimeStop %[[#Casted2]], 72
 define spir_func void @foo(ptr noundef byval(%tprange) align 8 %_arg_UserRange) {
   %RoundedRangeKernel = alloca %tprange, align 8
-  call void @llvm.lifetime.start.p0(i64 72, ptr nonnull %RoundedRangeKernel) #7
+  call void @llvm.lifetime.start.p0(i64 72, ptr nonnull %RoundedRangeKernel)
   call void @llvm.memcpy.p0.p0.i64(ptr align 8 %RoundedRangeKernel, ptr align 8 %_arg_UserRange, i64 16, i1 false)
   %KernelFunc = getelementptr inbounds i8, ptr %RoundedRangeKernel, i64 16
-  call void @llvm.lifetime.end.p0(i64 72, ptr nonnull %RoundedRangeKernel) #7
+  call void @llvm.lifetime.end.p0(i64 72, ptr nonnull %RoundedRangeKernel)
+  ret void
+}
+
+; CHECK: OpFunction
+; CHECK: %[[#BarVar:]] = OpVariable
+; CHECK: OpLifetimeStart %[[#BarVar]], 0
+; CHECK: OpCopyMemorySized
+; CHECK: OpBitcast
+; CHECK: OpInBoundsPtrAccessChain
+; CHECK: OpLifetimeStop %[[#BarVar]], 0
+define spir_func void @bar(ptr noundef byval(%tprange) align 8 %_arg_UserRange) {
+  %RoundedRangeKernel = alloca %tprange, align 8
+  call void @llvm.lifetime.start.p0(i64 -1, ptr nonnull %RoundedRangeKernel)
+  call void @llvm.memcpy.p0.p0.i64(ptr align 8 %RoundedRangeKernel, ptr align 8 %_arg_UserRange, i64 16, i1 false)
+  %KernelFunc = getelementptr inbounds i8, ptr %RoundedRangeKernel, i64 16
+  call void @llvm.lifetime.end.p0(i64 -1, ptr nonnull %RoundedRangeKernel)
+  ret void
+}
+
+; CHECK: OpFunction
+; CHECK: %[[#TestVar:]] = OpVariable
+; CHECK: OpLifetimeStart %[[#TestVar]], 1
+; CHECK: OpCopyMemorySized
+; CHECK: OpInBoundsPtrAccessChain
+; CHECK: OpLifetimeStop %[[#TestVar]], 1
+define spir_func void @test(ptr noundef align 8 %_arg) {
+  %var = alloca i8, align 8
+  call void @llvm.lifetime.start.p0(i64 1, ptr nonnull %var)
+  call void @llvm.memcpy.p0.p0.i64(ptr align 8 %var, ptr align 8 %_arg, i64 1, i1 false)
+  %KernelFunc = getelementptr inbounds i8, ptr %var, i64 0
+  call void @llvm.lifetime.end.p0(i64 1, ptr nonnull %var)
   ret void
 }