Fix GEP generation for reverse translation of OpCompositeConstruct (#2300)

Author: vmaksimo

lib/SPIRV/SPIRVReader.cpp

@@ -2262,7 +2262,7 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       // 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);
+            AT, Alloca, {getInt32(M, 0), getInt32(M, I)}, "gep", BB);
         GEP->setIsInBounds(true);
         new StoreInst(Constituents[I], GEP, false, BB);
       }
@@ -2281,7 +2281,7 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       // 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);
+            ST, Alloca, {getInt32(M, 0), getInt32(M, I)}, "gep", BB);
         GEP->setIsInBounds(true);
         new StoreInst(Constituents[I], GEP, false, BB);
       }

test/composite_construct_array_non_constant.spvasm

@@ -7,13 +7,13 @@
 
 ; CHECK: define spir_func [4 x i8] @non_constant_array_elements(i8 %[[#ARG0:]], i8 %[[#ARG1:]])
 ; CHECK: %[[#ArrayPtr:]] = alloca [4 x i8]
-; CHECK: %[[GEP:[0-9a-z.]+]] = getelementptr inbounds i8, ptr %[[#ArrayPtr]], i32 0
+; CHECK: %[[GEP:[0-9a-z.]+]] = getelementptr inbounds [4 x i8], ptr %[[#ArrayPtr]], i32 0, i32 0
 ; CHECK: store i8 %[[#ARG1]], ptr %[[GEP]]
-; CHECK: %[[GEP1:[0-9a-z.]+]] = getelementptr inbounds i8, ptr %[[#ArrayPtr]], i32 1
+; CHECK: %[[GEP1:[0-9a-z.]+]] = getelementptr inbounds [4 x i8], ptr %[[#ArrayPtr]], i32 0, i32 1
 ; CHECK: store i8 %[[#ARG0]], ptr %[[GEP1]]
-; CHECK: %[[GEP2:[0-9a-z.]+]] = getelementptr inbounds i8, ptr %[[#ArrayPtr]], i32 2
+; CHECK: %[[GEP2:[0-9a-z.]+]] = getelementptr inbounds [4 x i8], ptr %[[#ArrayPtr]], i32 0, i32 2
 ; CHECK: store i8 0, ptr %[[GEP2]]
-; CHECK: %[[GEP3:[0-9a-z.]+]] = getelementptr inbounds i8, ptr %[[#ArrayPtr]], i32 3
+; CHECK: %[[GEP3:[0-9a-z.]+]] = getelementptr inbounds [4 x i8], ptr %[[#ArrayPtr]], i32 0, i32 3
 ; CHECK: store i8 10, ptr %[[GEP3]]
 
 ; CHECK: %[[LoadArr:[0-9a-z.]+]] = load [4 x i8], ptr %[[#ArrayPtr]]

test/composite_construct_struct_non_constant.spt

@@ -1,14 +1,14 @@
 ; 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
+; RUN: llvm-spirv -r %t.spv -o %t.rev.bc
+; RUN: llvm-dis %t.rev.bc
+; RUN: FileCheck < %t.rev.ll %s
 
 ; CHECK: %[[StructTy:[0-9a-z.]+]] = type { float, i32 }
 ; CHECK: %[[#StructPtr:]] = alloca %[[StructTy]]
-; CHECK: %[[GEP:[0-9a-z.]+]] = getelementptr inbounds float, ptr %[[#StructPtr]], i32 0
+; CHECK: %[[GEP:[0-9a-z.]+]] = getelementptr inbounds %[[StructTy]], ptr %[[#StructPtr]], i32 0, i32 0
 ; CHECK: store float %[[#]], ptr %[[GEP]]
-; CHECK: %[[GEP1:[0-9a-z.]+]] = getelementptr inbounds i32, ptr %[[#StructPtr]], i32 1
+; CHECK: %[[GEP1:[0-9a-z.]+]] = getelementptr inbounds %[[StructTy]], ptr %[[#StructPtr]], i32 0, i32 1
 ; CHECK: store i32 %[[#]], ptr %[[GEP1]]
 ; CHECK: %[[LoadStr:[0-9a-z.]+]] = load %[[StructTy]], ptr %[[#StructPtr]]
 ; CHECK: ret %[[StructTy]] %[[LoadStr]]