[AsmParser] Check whether use is callee when determining function type

The code ended up treating a use in a call argument as if it were
a call. Make sure this is actually the callee use.

Author: nikic

llvm/lib/AsmParser/LLParser.cpp

@@ -306,9 +306,9 @@ bool LLParser::validateEndOfModule(bool UpgradeDebugInfo) {
   for (const auto &[Name, Info] : make_early_inc_range(ForwardRefVals)) {
     auto GetCommonFunctionType = [](Value *V) -> FunctionType * {
       FunctionType *FTy = nullptr;
-      for (User *U : V->users()) {
-        auto *CB = dyn_cast<CallBase>(U);
-        if (!CB || (FTy && FTy != CB->getFunctionType()))
+      for (Use &U : V->uses()) {
+        auto *CB = dyn_cast<CallBase>(U.getUser());
+        if (!CB || !CB->isCallee(&U) || (FTy && FTy != CB->getFunctionType()))
           return nullptr;
         FTy = CB->getFunctionType();
       }

llvm/test/Assembler/incomplete-ir-declarations.ll

@@ -4,6 +4,7 @@
 ; CHECK: @g1 = external global i8
 ; CHECK: @g2 = external global i8
 ; CHECK: @g3 = external global i8
+; CHECK: @g4 = external global i8
 
 ; CHECK: declare void @fn1(i32)
 
@@ -12,9 +13,10 @@ define ptr @test() {
   call void @fn1(i32 1)
   call void @fn2(i32 2)
   call void @fn2(i32 2, i32 3)
-  load i32, ptr @g1
-  store i32 0, ptr @g1
-  load i32, ptr @g1
-  load i64, ptr @g2
-  ret ptr @g3
+  call void @fn2(ptr @g1)
+  load i32, ptr @g2
+  store i32 0, ptr @g2
+  load i32, ptr @g3
+  load i64, ptr @g3
+  ret ptr @g4
 }