[GR-59621] Backport to 24.1: ensure only safepoint usages left

PullRequest: graal/19522

Author: elkorchi

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/nodes/loop/LoopFragmentInside.java

@@ -343,6 +343,11 @@ protected CompareNode placeNewSegmentAndCleanup(LoopEx loop, EconomicMap<Node, N
                         lastCodeNode = newAnchoringPointAfterPrevIteration;
                     }
                     newSegmentBegin.replaceAtUsages(lastCodeNode, InputType.Guard, InputType.Anchor);
+
+                    // at this point only safepoint usages can live here
+                    assert newSegmentBegin.usages().filter(x -> !(x instanceof SafepointNode)).count() == 0 : "Must only have safepoint(association) usages left for " + newSegmentBegin + " usages=" +
+                                    newSegmentBegin.usages();
+                    newSegmentBegin.replaceAtUsages(mainLoopBegin, InputType.Association);
                 }
                 lastCodeNode.replaceFirstSuccessor(loopEndNode, newSegmentFirstNode);
                 newSegmentLastNode.replaceFirstSuccessor(newSegmentEnd, loopEndNode);