diff --git a/llvm/lib/Target/X86/X86LowerAMXType.cpp b/llvm/lib/Target/X86/X86LowerAMXType.cpp
--- a/llvm/lib/Target/X86/X86LowerAMXType.cpp
+++ b/llvm/lib/Target/X86/X86LowerAMXType.cpp
@@ -488,7 +488,7 @@
   // Get tile shape.
   IntrinsicInst *II = nullptr;
   if (IsPHI) {
-    Value *PhiOp = dyn_cast<PHINode>(V)->getIncomingValue(0);
+    Value *PhiOp = cast<PHINode>(V)->getIncomingValue(0);
     II = cast<IntrinsicInst>(PhiOp);
   } else {
     II = cast<IntrinsicInst>(V);