Prevent duplicate array type insertion into TypeMap. (#3186)

Check if an array type exists in TypeMap before inserting it to prevent
duplications.

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@2a5a4e71d79d074

Author: maarquitos14

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -465,11 +465,13 @@ SPIRVType *LLVMToSPIRVBase::transType(Type *T) {
             ConstantInt::get(getSizetType(), ArraySize, false), nullptr)));
     mapType(T, TransType);
     if (ElTy->isPointerTy()) {
-      mapType(
+      Type *ArrTy =
           ArrayType::get(TypedPointerType::get(Type::getInt8Ty(*Ctx),
                                                ElTy->getPointerAddressSpace()),
-                         ArraySize),
-          TransType);
+                         ArraySize);
+      LLVMToSPIRVTypeMap::iterator Loc = TypeMap.find(ArrTy);
+      if (Loc == TypeMap.end())
+        mapType(ArrTy, TransType);
     }
     return TransType;
   }

llvm-spirv/test/duplicate-types.ll

@@ -0,0 +1,19 @@
+; Check that we don't end up with duplicated array types in TypeMap.
+; No FileCheck needed, we only want to check the absence of errors.
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -o %t.spv
+; RUN: spirv-val %t.spv
+
+; ModuleID = 'duplicate-array-types'
+target datalayout = "e-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-n8:16:32:64-G1"
+target triple = "spir64-unknown-unknown"
+
+%duplicate = type { [2 x ptr addrspace(4)] }
+
+; Function Attrs: mustprogress norecurse nounwind
+define spir_kernel void @foo() {
+entry:
+  alloca [2 x ptr addrspace(4)], align 8
+  alloca %duplicate, align 8
+  ret void
+}