[FuncSpec] Invalidate analysis by setting MadeChanges explicitly (#155833)

As reported in
https://github.com/llvm/llvm-project/issues/154668#issuecomment-3233294078,
we missed invalidating analysis as we don't set the MadeChanges to true
after removing dead functions.

This patch makes it explicit to remove the dead functions marked by
FuncSpec in SCCP and set MadeChanges correctly.

llvm/lib/Transforms/IPO/SCCP.cpp

diff --git a/llvm/lib/Transforms/IPO/SCCP.cpp b/llvm/lib/Transforms/IPO/SCCP.cpp
index f4961fa..2ecadd5 100644
--- a/llvm/lib/Transforms/IPO/SCCP.cpp
+++ b/llvm/lib/Transforms/IPO/SCCP.cpp
@@ -170,9 +170,12 @@
     if (F.isDeclaration())
       continue;
     // Skip the dead functions marked by FunctionSpecializer, avoiding removing
-    // blocks in dead functions.
-    if (IsFuncSpecEnabled && Specializer.isDeadFunction(&F))
+    // blocks in dead functions. Set MadeChanges if there is any dead function
+    // that will be removed later.
+    if (IsFuncSpecEnabled && Specializer.isDeadFunction(&F)) {
+      MadeChanges = true;
       continue;
+    }
 
     SmallVector<BasicBlock *, 512> BlocksToErase;