Improve constant expressions lowering for function pointers.

zuban32 · AlexeySachkov · commit 246a4ef1dc9e · 2020-06-09T13:24:08.000+03:00
Extend constexprs lowering support to lower constant vector of pure function pointers
w/o any transformations inside.
diff --git a/llvm-spirv/lib/SPIRV/SPIRVLowerConstExpr.cpp b/llvm-spirv/lib/SPIRV/SPIRVLowerConstExpr.cpp
@@ -113,7 +113,6 @@ bool SPIRVLowerConstExpr::runOnModule(Module &Module) {
 
 void SPIRVLowerConstExpr::visit(Module *M) {
   for (auto &I : M->functions()) {
-    std::map<ConstantExpr *, Instruction *> CMap;
     std::list<Instruction *> WorkList;
     for (auto &BI : I) {
       for (auto &II : BI) {
@@ -124,7 +123,10 @@ void SPIRVLowerConstExpr::visit(Module *M) {
     while (!WorkList.empty()) {
       auto II = WorkList.front();
 
-      auto LowerOp = [&II, &FBegin, &I](ConstantExpr *CE) {
+      auto LowerOp = [&II, &FBegin, &I](Value *V) -> Value * {
+        if (isa<Function>(V))
+          return V;
+        auto *CE = cast<ConstantExpr>(V);
         SPIRVDBG(dbgs() << "[lowerConstantExpressions] " << *CE;)
         auto ReplInst = CE->getAsInstruction();
         auto InsPoint = II->getParent() == &*FBegin ? II : &FBegin->back();
@@ -149,25 +151,30 @@ void SPIRVLowerConstExpr::visit(Module *M) {
       for (unsigned OI = 0, OE = II->getNumOperands(); OI != OE; ++OI) {
         auto Op = II->getOperand(OI);
         auto *Vec = dyn_cast<ConstantVector>(Op);
-        if (Vec && std::all_of(Vec->op_begin(), Vec->op_end(),
-                               [](Value *V) { return isa<ConstantExpr>(V); })) {
+        if (Vec && std::all_of(Vec->op_begin(), Vec->op_end(), [](Value *V) {
+              return isa<ConstantExpr>(V) || isa<Function>(V);
+            })) {
           // Expand a vector of constexprs and construct it back with series of
           // insertelement instructions
-          std::list<Instruction *> ReplList;
-          std::transform(
-              Vec->op_begin(), Vec->op_end(), std::back_inserter(ReplList),
-              [LowerOp](Value *V) { return LowerOp(cast<ConstantExpr>(V)); });
+          std::list<Value *> OpList;
+          std::transform(Vec->op_begin(), Vec->op_end(),
+                         std::back_inserter(OpList),
+                         [LowerOp](Value *V) { return LowerOp(V); });
           Value *Repl = nullptr;
           unsigned Idx = 0;
-          for (auto V : ReplList)
+          std::list<Instruction *> ReplList;
+          for (auto V : OpList) {
+            if (auto *Inst = dyn_cast<Instruction>(V))
+              ReplList.push_back(Inst);
             Repl = InsertElementInst::Create(
                 (Repl ? Repl : UndefValue::get(Vec->getType())), V,
                 ConstantInt::get(Type::getInt32Ty(M->getContext()), Idx++), "",
                 II);
+          }
           II->replaceUsesOfWith(Op, Repl);
           WorkList.splice(WorkList.begin(), ReplList);
         } else if (auto CE = dyn_cast<ConstantExpr>(Op))
-          WorkList.push_front(LowerOp(CE));
+          WorkList.push_front(cast<Instruction>(LowerOp(CE)));
       }
     }
   }
diff --git a/llvm-spirv/lib/SPIRV/SPIRVWriter.cpp b/llvm-spirv/lib/SPIRV/SPIRVWriter.cpp
@@ -1302,13 +1302,22 @@ SPIRVValue *LLVMToSPIRV::transValueWithoutDecoration(Value *V,
 
   if (auto Ins = dyn_cast<InsertElementInst>(V)) {
     auto Index = Ins->getOperand(2);
-    if (auto Const = dyn_cast<ConstantInt>(Index))
+    if (auto Const = dyn_cast<ConstantInt>(Index)) {
+      SPIRVValue *InsVal = nullptr;
+      if (auto *F = dyn_cast<Function>(Ins->getOperand(1))) {
+        if (!BM->checkExtension(ExtensionID::SPV_INTEL_function_pointers,
+                                SPIRVEC_FunctionPointers, toString(V)))
+          return nullptr;
+        InsVal = BM->addFunctionPointerINTELInst(
+            transType(F->getType()),
+            static_cast<SPIRVFunction *>(transValue(F, BB)), BB);
+      } else
+        InsVal = transValue(Ins->getOperand(1), BB);
       return mapValue(V, BM->addCompositeInsertInst(
-                             transValue(Ins->getOperand(1), BB),
-                             transValue(Ins->getOperand(0), BB),
+                             InsVal, transValue(Ins->getOperand(0), BB),
                              std::vector<SPIRVWord>(1, Const->getZExtValue()),
                              BB));
-    else
+    } else
       return mapValue(
           V, BM->addVectorInsertDynamicInst(transValue(Ins->getOperand(0), BB),
                                             transValue(Ins->getOperand(1), BB),
diff --git a/llvm-spirv/test/constexpr_vector.ll b/llvm-spirv/test/constexpr_vector.ll
@@ -1,8 +1,7 @@
 ; RUN: llvm-as < %s | llvm-spirv -s | llvm-dis | FileCheck %s --check-prefix=CHECK-LLVM
 
 ; CHECK-LLVM: define dllexport void @vadd() {
-; CHECK-LLVM-NEXT: entry:
-; CHECK-LLVM-NEXT:   %Funcs = alloca <16 x i8>, align 16
+; CHECK-LLVM:   %Funcs = alloca <16 x i8>, align 16
 ; CHECK-LLVM-NEXT:   %0 = ptrtoint i32 (i32)* @_Z2f1u2CMvb32_j to i64
 ; CHECK-LLVM-NEXT:   %1 = bitcast i64 %0 to <8 x i8>
 ; CHECK-LLVM-NEXT:   %2 = extractelement <8 x i8> %1, i32 0
@@ -40,8 +39,12 @@
 ; CHECK-LLVM-NEXT:   %34 = insertelement <16 x i8> %33, i8 %18, i32 14
 ; CHECK-LLVM-NEXT:   %35 = insertelement <16 x i8> %34, i8 %19, i32 15
 ; CHECK-LLVM-NEXT:   store <16 x i8> %35, <16 x i8>* %Funcs, align 16
-; CHECK-LLVM-NEXT:   ret void
-; CHECK-LLVM-NEXT: }
+; CHECK-LLVM:        %Funcs1 = alloca <2 x i64>, align 16
+; CHECK-LLVM-NEXT:   %36 = ptrtoint i32 (i32)* @_Z2f1u2CMvb32_j to i64
+; CHECK-LLVM-NEXT:   %37 = ptrtoint i32 (i32)* @_Z2f2u2CMvb32_j to i64
+; CHECK-LLVM-NEXT:   %38 = insertelement <2 x i64> undef, i64 %36, i32 0
+; CHECK-LLVM-NEXT:   %39 = insertelement <2 x i64> %38, i64 %37, i32 1
+; CHECK-LLVM-NEXT:   store <2 x i64> %39, <2 x i64>* %Funcs1, align 16
 
 ; RUN: llvm-as < %s | llvm-spirv -spirv-text --spirv-ext=+SPV_INTEL_function_pointers | FileCheck %s --check-prefix=CHECK-SPIRV
 
@@ -115,5 +118,7 @@ define dllexport void @vadd() {
 entry:
   %Funcs = alloca <16 x i8>, align 16
   store <16 x i8> <i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 0), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 1), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 2), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 3), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 4), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 5), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 6), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64) to <8 x i8>), i32 7), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 0), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 1), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 2), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 3), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 4), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 5), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 6), i8 extractelement (<8 x i8> bitcast (i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64) to <8 x i8>), i32 7)>, <16 x i8>* %Funcs, align 16
+  %Funcs1 = alloca <2 x i64>, align 16
+  store <2 x i64> <i64 ptrtoint (i32 (i32)* @_Z2f1u2CMvb32_j to i64), i64 ptrtoint (i32 (i32)* @_Z2f2u2CMvb32_j to i64)>, <2 x i64>* %Funcs1, align 16
   ret void
 }
diff --git a/llvm-spirv/test/transcoding/SPV_INTEL_function_pointers/vector_elem.ll b/llvm-spirv/test/transcoding/SPV_INTEL_function_pointers/vector_elem.ll
@@ -0,0 +1,42 @@
+; RUN: llvm-as < %s | llvm-spirv -spirv-text --spirv-ext=+SPV_INTEL_function_pointers | FileCheck %s --check-prefix=CHECK-SPIRV
+
+; CHECK-SPIRV-DAG: 6 Name [[F1:[0-9+]]] "_Z2f1u2CMvb32_j"
+; CHECK-SPIRV-DAG: 6 Name [[F2:[0-9+]]] "_Z2f2u2CMvb32_j"
+; CHECK-SPIRV-DAG: 4 Name [[Funcs:[0-9]+]] "Funcs"
+
+; CHECK-SPIRV: 4 TypeInt [[TypeInt32:[0-9]+]] 32 0
+; CHECK-SPIRV: 4 TypeFunction [[TypeFunc:[0-9]+]] [[TypeInt32]] [[TypeInt32]]
+; CHECK-SPIRV: 4 TypePointer [[TypePtr:[0-9]+]] {{[0-9]+}} [[TypeFunc]]
+; CHECK-SPIRV: 4 TypeVector [[TypeVec:[0-9]+]] [[TypePtr]] [[TypeInt32]]
+; CHECK-SPIRV: 3 Undef [[TypeVec]] [[TypeUndef:[0-9]+]]
+
+; CHECK-SPIRV: 4 FunctionPointerINTEL [[TypePtr]] [[F1Ptr:[0-9]+]] [[F1]]
+; CHECK-SPIRV: 6 CompositeInsert [[TypeVec]] [[NewVec0:[0-9]+]] [[F1Ptr]] [[TypeUndef]] 0
+; CHECK-SPIRV: 4 FunctionPointerINTEL [[TypePtr]] [[F2Ptr:[0-9]+]] [[F2]]
+; CHECK-SPIRV: 6 CompositeInsert [[TypeVec]] [[NewVec1:[0-9]+]] [[F2Ptr]] [[NewVec0]] 1
+; CHECK-SPIRV: 5 Store [[Funcs]] [[NewVec1]] [[TypeInt32]] {{[0-9+]}}
+
+
+target datalayout = "e-p:32:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024"
+target triple = "spir-unknown-unknown"
+
+; Function Attrs: noinline norecurse nounwind readnone
+define internal i32 @_Z2f1u2CMvb32_j(i32 %x) {
+entry:
+  ret i32 %x
+}
+; Function Attrs: noinline norecurse nounwind readnone
+define internal i32 @_Z2f2u2CMvb32_j(i32 %x) {
+entry:
+  ret i32 %x
+}
+
+; Function Attrs: noinline nounwind
+define dllexport void @vadd() {
+entry:
+  %Funcs = alloca <2 x i32 (i32)*>, align 16
+  %0 = insertelement <2 x i32 (i32)*> undef, i32 (i32)* @_Z2f1u2CMvb32_j, i32 0
+  %1 = insertelement <2 x i32 (i32)*> %0, i32 (i32)* @_Z2f2u2CMvb32_j, i32 1
+  store <2 x i32 (i32)*> %1, <2 x i32 (i32)*>* %Funcs, align 16
+  ret void
+}
