AMDGPU: Fix annotate kernel features through casted calls

I thought I was testing this before, but the workitem id x
case isn't great since it's mandatory in the parent kernel.

llvm/lib/Target/AMDGPU/AMDGPUAnnotateKernelFeatures.cpp

@@ -289,7 +289,8 @@ bool AMDGPUAnnotateKernelFeatures::addFeatureAttributes(Function &F) {
     for (Instruction &I : BB) {
       CallSite CS(&I);
       if (CS) {
-        Function *Callee = CS.getCalledFunction();
+        const Function *Callee
+          = dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts());
 
         // TODO: Do something with indirect calls.
         if (!Callee) {

llvm/test/CodeGen/AMDGPU/annotate-kernel-features-hsa-call.ll

@@ -295,6 +295,20 @@ define amdgpu_kernel void @func_kern_defined() #3 {
   ret void
 }
 
+; HSA: define i32 @use_dispatch_ptr_ret_type() #20 {
+define i32 @use_dispatch_ptr_ret_type() #1 {
+  %dispatch.ptr = call i8 addrspace(4)* @llvm.amdgcn.dispatch.ptr()
+  store volatile i8 addrspace(4)* %dispatch.ptr, i8 addrspace(4)* addrspace(1)* undef
+  ret i32 0
+}
+
+; HSA: define float @func_indirect_use_dispatch_ptr_constexpr_cast_func() #20 {
+define float @func_indirect_use_dispatch_ptr_constexpr_cast_func() #1 {
+  %f = call float bitcast (i32()* @use_dispatch_ptr_ret_type to float()*)()
+  %fadd = fadd float %f, 1.0
+  ret float %fadd
+}
+
 attributes #0 = { nounwind readnone speculatable }
 attributes #1 = { nounwind "target-cpu"="fiji" }
 attributes #2 = { nounwind "target-cpu"="gfx900" }
@@ -320,3 +334,4 @@ attributes #3 = { nounwind }
 ; HSA: attributes #17 = { nounwind "uniform-work-group-size"="false" }
 ; HSA: attributes #18 = { nounwind }
 ; HSA: attributes #19 = { nounwind "amdgpu-calls" "uniform-work-group-size"="false" }
+; HSA: attributes #20 = { nounwind "amdgpu-dispatch-ptr" "target-cpu"="fiji" }