[clang] [Clang][CodeGen] Report when an alias points to an incompatible target (PR #192397)

[Aaron Ballman via cfe-commits]

================
@@ -804,6 +804,49 @@ void CodeGenModule::checkAliases() {
       continue;
     }
 
+    if (!IsIFunc) {
+      // Function declarations can only alias functions (including IFUNCs).
+      // Similarly, variable declarations can only alias variables.
+      if (isa<FunctionDecl>(D) !=
+          (isa<llvm::Function>(GV) || isa<llvm::GlobalIFunc>(GV))) {
----------------
AaronBallman wrote:

```suggestion
      if (isa<FunctionDecl>(D) != isa<llvm::Function, llvm::GlobalIFunc>(GV))) {
```

https://github.com/llvm/llvm-project/pull/192397