[CallSiteSplitting] Don't copy !llvm.loop metadata to split block

llvm/lib/Transforms/Scalar/CallSiteSplitting.cpp

@@ -328,6 +328,12 @@ static void splitCallSite(CallBase &CB,
         DTU);
     assert(SplitBlock && "Unexpected new basic block split.");
 
+    // The split block shouldn't inherit !llvm.loop metadata.
+    Instruction *SplitTerm = SplitBlock->getTerminator();
+    SplitTerm->eraseMetadataIf([](unsigned MDKind, MDNode *Node) {
+      return MDKind == LLVMContext::MD_loop;
+    });
+
     auto *NewCI =
         cast<CallBase>(&*std::prev(SplitBlock->getTerminator()->getIterator()));
     addConditions(*NewCI, Preds[i].second);

llvm/test/Transforms/CallSiteSplitting/loop-metadata.ll

@@ -0,0 +1,44 @@
+; Verify that we don't add incorrect llvm.loop metadata to a
+; non-latching branch.
+
+; RUN: opt -passes=callsite-splitting -S < %s 2>&1 | FileCheck %s
+
+; CHECK-NOT: br label %x{{.*}}, !llvm.loop !0
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define internal void @foo(i1 %0, i1 %1, i1 %2) {
+  br i1 %0, label %x1, label %x2
+
+x1:
+  br label %x16
+
+x2:
+  br label %x16
+
+x16:
+  %x17 = phi i32 [ 0, %x1 ], [ 1, %x2 ]
+  br i1 %1, label %x55, label %x46
+
+x46:
+  %x47 = icmp eq i32 %x17, 0
+  br i1 %x47, label %x49, label %x48
+
+x48:
+  br i1 %2, label %x49, label %x48, !llvm.loop !0
+
+x49:
+  %x50 = tail call fastcc i32 @func1(i32 noundef %x17)
+  br label %x55
+
+x55:
+  ret void
+}
+
+define internal fastcc i32 @func1(i32 noundef %0) unnamed_addr {
+  ret i32 13
+}
+
+!0 = distinct !{!0, !1}
+!1 = !{!"llvm.loop.mustprogress"}