[sycl-post-link] Don't split module if function pointer has a user that's not CallInst (intel#4657)

Author: wenju-he

llvm/test/tools/sycl-post-link/auto-module-split-func-ptr.ll

@@ -0,0 +1,38 @@
+; RUN: sycl-post-link -split=auto -symbols -S %s -o %t.table
+; RUN: FileCheck %s -input-file=%t_0.sym
+
+; This test checkes that module is not split if function pointer's user is not
+; CallInst.
+
+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"
+target triple = "spir64_x86_64-unknown-unknown"
+
+@_Z2f1iTable = weak global [1 x i32 (i32)*] [i32 (i32)* @_Z2f1i], align 8
+
+; Function Attrs: mustprogress nofree norecurse nosync nounwind readnone willreturn
+define dso_local spir_func i32 @_Z2f1i(i32 %a) #0 {
+entry:
+  ret i32 %a
+}
+
+; Function Attrs: convergent norecurse
+define weak_odr dso_local spir_kernel void @kernel1() #1 {
+entry:
+  %0 = call i32 @indirect_call(i32 (i32)* addrspace(4)* addrspacecast (i32 (i32)** getelementptr inbounds ([1 x i32 (i32)*], [1 x i32 (i32)*]* @_Z2f1iTable, i64 0, i64 0) to i32 (i32)* addrspace(4)*), i32 0)
+  ret void
+}
+
+; Function Attrs: convergent norecurse
+define dso_local spir_kernel void @kernel2() #2 {
+entry:
+  ret void
+}
+
+declare dso_local spir_func i32 @indirect_call(i32 (i32)* addrspace(4)*, i32) local_unnamed_addr
+
+attributes #0 = { mustprogress nofree norecurse nosync nounwind readnone willreturn }
+attributes #1 = { convergent norecurse "sycl-module-id"="TU1.cpp" }
+attributes #2 = { convergent norecurse "sycl-module-id"="TU2.cpp" }
+
+; CHECK: kernel1
+; CHECK: kernel2

llvm/tools/sycl-post-link/sycl-post-link.cpp

@@ -239,6 +239,10 @@ static KernelMapEntryScope selectDeviceCodeSplitScopeAutomatically(Module &M) {
         }
       }
     }
+    // Function pointer is used somewhere. Follow the same rule as above.
+    for (const auto *U : F.users())
+      if (!isa<CallInst>(U))
+        return Scope_Global;
   }
 
   // At the moment, we assume that per-source split is the best way of splitting