[Backport to 16] Fix SPIR-V global to function replacement for differing load types

lib/SPIRV/SPIRVUtil.cpp

@@ -1913,19 +1913,20 @@ bool isSPIRVBuiltinVariable(GlobalVariable *GV,
 /// are accumulated in the AccumulatedOffset parameter, which will eventually be
 /// used to figure out which index of a variable is being used.
 static void replaceUsesOfBuiltinVar(Value *V, const APInt &AccumulatedOffset,
-                                    Function *ReplacementFunc) {
+                                    Function *ReplacementFunc,
+                                    GlobalVariable *GV) {
   const DataLayout &DL = ReplacementFunc->getParent()->getDataLayout();
   SmallVector<Instruction *, 4> InstsToRemove;
   for (User *U : V->users()) {
     if (auto *Cast = dyn_cast<CastInst>(U)) {
-      replaceUsesOfBuiltinVar(Cast, AccumulatedOffset, ReplacementFunc);
+      replaceUsesOfBuiltinVar(Cast, AccumulatedOffset, ReplacementFunc, GV);
       InstsToRemove.push_back(Cast);
     } else if (auto *GEP = dyn_cast<GetElementPtrInst>(U)) {
       APInt NewOffset = AccumulatedOffset.sextOrTrunc(
           DL.getIndexSizeInBits(GEP->getPointerAddressSpace()));
       if (!GEP->accumulateConstantOffset(DL, NewOffset))
         llvm_unreachable("Illegal GEP of a SPIR-V builtin variable");
-      replaceUsesOfBuiltinVar(GEP, NewOffset, ReplacementFunc);
+      replaceUsesOfBuiltinVar(GEP, NewOffset, ReplacementFunc, GV);
       InstsToRemove.push_back(GEP);
     } else if (auto *Load = dyn_cast<LoadInst>(U)) {
       // Figure out which index the accumulated offset corresponds to. If we
@@ -1948,7 +1949,12 @@ static void replaceUsesOfBuiltinVar(Value *V, const APInt &AccumulatedOffset,
       } else {
         // The function has an index parameter.
         if (auto *VecTy = dyn_cast<FixedVectorType>(Load->getType())) {
-          if (!Index.isZero())
+          // Reconstruct the original global variable vector because
+          // the load type may not match.
+          // global <3 x i64>, load <6 x i32>
+          VecTy = cast<FixedVectorType>(GV->getValueType());
+          if (!Index.isZero() || DL.getTypeSizeInBits(VecTy) !=
+                                     DL.getTypeSizeInBits(Load->getType()))
             llvm_unreachable("Illegal use of a SPIR-V builtin variable");
           Replacement = UndefValue::get(VecTy);
           for (unsigned I = 0; I < VecTy->getNumElements(); I++) {
@@ -1958,6 +1964,19 @@ static void replaceUsesOfBuiltinVar(Value *V, const APInt &AccumulatedOffset,
                     Builder.CreateCall(ReplacementFunc, {Builder.getInt32(I)})),
                 Builder.getInt32(I));
           }
+          // Insert a bitcast from the reconstructed vector to the load vector
+          // type in case they are different.
+          // Input:
+          // %1 = load <6 x i32>, ptr addrspace(1) %0, align 32
+          // %2 = extractelement <6 x i32> %1, i32 0
+          // %3 = add i32 5, %2
+          // Modified:
+          // < reconstruct global vector elements 0 and 1 >
+          // %2 = insertelement <3 x i64> %0, i64 %1, i32 2
+          // %3 = bitcast <3 x i64> %2 to <6 x i32>
+          // %4 = extractelement <6 x i32> %3, i32 0
+          // %5 = add i32 5, %4
+          Replacement = Builder.CreateBitCast(Replacement, Load->getType());
         } else if (Load->getType() == ScalarTy) {
           Replacement = setAttrByCalledFunc(Builder.CreateCall(
               ReplacementFunc, {Builder.getInt32(Index.getZExtValue())}));
@@ -2011,7 +2030,7 @@ bool lowerBuiltinVariableToCall(GlobalVariable *GV,
     Func->setDoesNotAccessMemory();
   }
 
-  replaceUsesOfBuiltinVar(GV, APInt(64, 0), Func);
+  replaceUsesOfBuiltinVar(GV, APInt(64, 0), Func, GV);
   return true;
 }
 

test/transcoding/builtin_vars_different_type.ll

@@ -0,0 +1,27 @@
+; RUN: llvm-as %s -o %t.bc
+; RUN: llvm-spirv %t.bc -o %t.spv -spirv-ext=+SPV_INTEL_vector_compute
+; RUN: llvm-spirv -r %t.spv --spirv-target-env=SPV-IR -o %t.out.bc
+; RUN: llvm-dis %t.out.bc -o - | FileCheck %s --check-prefix=CHECK-SPV-IR
+
+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"
+
+@__spirv_BuiltInGlobalInvocationId = external dso_local local_unnamed_addr addrspace(1) constant <3 x i64>, align 32
+
+; Function Attrs: nounwind readnone
+define spir_kernel void @f() {
+entry:
+  %0 = load <6 x i32>, ptr addrspace(1) @__spirv_BuiltInGlobalInvocationId, align 32
+  %1 = extractelement <6 x i32> %0, i64 0
+  %2 = add i32 5, %1
+  ret void
+; CHECK-SPV-IR: %[[#ID0:]] = call spir_func i64 @_Z33__spirv_BuiltInGlobalInvocationIdi(i32 0) #1
+; CHECK-SPV-IR: %[[#ID1:]] = insertelement <3 x i64> undef, i64 %[[#ID0]], i32 0
+; CHECK-SPV-IR: %[[#ID2:]] = call spir_func i64 @_Z33__spirv_BuiltInGlobalInvocationIdi(i32 1) #1
+; CHECK-SPV-IR: %[[#ID3:]] = insertelement <3 x i64> %[[#ID1]], i64 %[[#ID2]], i32 1
+; CHECK-SPV-IR: %[[#ID4:]] = call spir_func i64 @_Z33__spirv_BuiltInGlobalInvocationIdi(i32 2) #1
+; CHECK-SPV-IR: %[[#ID5:]] = insertelement <3 x i64> %[[#ID3]], i64 %[[#ID4]], i32 2
+; CHECK-SPV-IR: %[[#ID6:]] = bitcast <3 x i64> %[[#ID5]] to <6 x i32>
+; CHECK-SPV-IR: %[[#ID7:]] = extractelement <6 x i32> %[[#ID6]], i32 0
+; CHECK-SPV-IR: = add i32 5, %[[#ID7]]
+}