Fix reverse translation of non-constant values of OpCompositeConstruct (#2256)

This patch introduces a way to use runtime values for structure fields.

Co-authored-by: Arvind Sudarsanam <[email protected]>

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@a6f017a

Author: vmaksimo

llvm-spirv/lib/SPIRV/SPIRVReader.cpp

@@ -2235,9 +2235,14 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
     auto *CC = static_cast<SPIRVCompositeConstruct *>(BV);
     auto Constituents = transValue(CC->getOperands(), F, BB);
     std::vector<Constant *> CV;
+    bool HasRtValues = false;
     for (const auto &I : Constituents) {
-      CV.push_back(dyn_cast<Constant>(I));
+      auto *C = dyn_cast<Constant>(I);
+      CV.push_back(C);
+      if (!HasRtValues && C == nullptr)
+        HasRtValues = true;
     }
+
     switch (static_cast<size_t>(BV->getType()->getOpCode())) {
     case OpTypeVector:
       return mapValue(BV, ConstantVector::get(CV));
@@ -2247,7 +2252,22 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
     }
     case OpTypeStruct: {
       auto *ST = cast<StructType>(transType(CC->getType()));
-      return mapValue(BV, ConstantStruct::get(ST, CV));
+      if (!HasRtValues)
+        return mapValue(BV, ConstantStruct::get(ST, CV));
+
+      AllocaInst *Alloca = new AllocaInst(ST, SPIRAS_Private, "", BB);
+
+      // get pointer to the element of structure
+      // store the result of argument
+      for (size_t I = 0; I < Constituents.size(); I++) {
+        auto *GEP = GetElementPtrInst::Create(
+            Constituents[I]->getType(), Alloca, {getInt32(M, I)}, "gep", BB);
+        GEP->setIsInBounds(true);
+        new StoreInst(Constituents[I], GEP, false, BB);
+      }
+
+      auto *Load = new LoadInst(ST, Alloca, "load", false, BB);
+      return mapValue(BV, Load);
     }
     case internal::OpTypeJointMatrixINTEL:
     case OpTypeCooperativeMatrixKHR:

llvm-spirv/test/composite_construct_struct_non_constant.spt

@@ -0,0 +1,48 @@
+; RUN: llvm-spirv %s -to-binary -o %t.spv
+; RUN: spirv-val %t.spv
+; RUN: llvm-spirv -r %t.spv -o %t.bc
+; RUN: llvm-dis %t.bc
+; RUN: FileCheck < %t.ll %s --check-prefix=CHECK-LLVM
+
+; CHECK-LLVM: %[[StructTy:[0-9a-z.]+]] = type { float, i32 }
+; CHECK-LLVM: %[[#StructPtr:]] = alloca %[[StructTy]]
+; CHECK-LLVM: %[[GEP:[0-9a-z.]+]] = getelementptr inbounds float, ptr %[[#StructPtr]], i32 0
+; CHECK-LLVM: store float %[[#]], ptr %[[GEP]]
+; CHECK-LLVM: %[[GEP1:[0-9a-z.]+]] = getelementptr inbounds i32, ptr %[[#StructPtr]], i32 1
+; CHECK-LLVM: store i32 %[[#]], ptr %[[GEP1]]
+; CHECK-LLVM: %[[LoadStr:[0-9a-z.]+]] = load %[[StructTy]], ptr %[[#StructPtr]]
+; CHECK-LLVM: ret %[[StructTy]] %[[LoadStr]]
+
+119734787 65536 393230 23 0 
+2 Capability Addresses 
+2 Capability Linkage 
+2 Capability Kernel 
+5 ExtInstImport 1 "OpenCL.std" 
+3 MemoryModel 2 2 
+3 Source 0 0 
+5 Name 2 "structtype" 
+9 Name 6 "non_constant_struct_fields" 
+11 Decorate 6 LinkageAttributes "non_constant_struct_fields" Export 
+4 Decorate 9 Alignment 4 
+4 Decorate 11 Alignment 4 
+4 TypeInt 4 32 0 
+4 Constant 4 17 0 
+4 Constant 4 20 1 
+3 TypeFloat 3 32 
+4 TypeStruct 2 3 4 
+
+3 TypeFunction 5 2 
+4 TypePointer 8 7 4 
+4 TypePointer 10 7 3 
+
+5 Function 2 6 0 5 
+
+2 Label 7 
+4 Variable 8 9 7 
+4 Variable 10 11 7 
+4 Load 4 12 9 
+4 Load 3 13 11 
+5 CompositeConstruct 2 14 13 12
+2 ReturnValue 14 
+
+1 FunctionEnd