Fix GEP lowering pass in VC

The `ptrtoint` folding function should take care of `<1 x ptr>` bitcast
to and from `ptr`.

Author: vmustya

IGC/VectorCompiler/lib/GenXCodeGen/GenXGEPLowering.cpp

@@ -137,8 +137,13 @@ Value *GenXGEPLowering::visitPtrToIntInst(PtrToIntInst &PTI) {
       // The `addrspacecast` is just no-op so it can be eliminated
       Src = Cast->getOperand(0);
     } else if (isa<BitCastInst>(Cast)) {
+      auto *Arg = Cast->getOperand(0);
+      auto *ArgTy = Arg->getType();
+      auto *CastTy = Cast->getType();
+      if (ArgTy->isVectorTy() != CastTy->isVectorTy())
+        break;
       // The `bitcast` is just no-op so it can be eliminated
-      Src = Cast->getOperand(0);
+      Src = Arg;
     } else {
       // We found `inttoptr`, getting rid of `ptrtoint`
       if (isa<IntToPtrInst>(Cast))

IGC/VectorCompiler/test/GenXGEPLowering/fold-ptrtoint.ll

@@ -63,3 +63,14 @@ label:                                                ; preds = %entry
   %splat = shufflevector <16 x i64> %ins, <16 x i64> undef, <16 x i32> zeroinitializer
   ret void
 }
+
+; CHECK-LABEL: @test_bitcast_vector_to_scalar
+define i64 @test_bitcast_vector_to_scalar(<1 x i8*> %vptr) {
+  %ptr = bitcast <1 x i8*> %vptr to i8*
+  %gep = getelementptr i8, i8* %ptr, i32 123
+  %addr = ptrtoint i8* %gep to i64
+  ; CHECK: [[PTI:%[^ ]+]] = ptrtoint i8* %ptr to i64
+  ; CHECK: [[ADD:%[^ ]+]] = add i64 [[PTI]], 123
+  ; CHECK: ret i64 [[ADD]]
+  ret i64 %addr
+}