[AliasSet] Fix UnknownInstructions printing

Summary:
AliasSet::print uses `I->printAsOperand` to print UnknownInstructions. The problem is that not all UnknownInstructions have names (e.g. call instructions). When such instructions are printed, they appear as `<badref>` in AliasSets, which is very confusing, as the values are perfectly valid.

This patch fixes that by printing UnknownInstructions without a name using `print` instead of `printAsOperand`.

Reviewers: asbirlea, chandlerc, sanjoy, grosser

Reviewed By: asbirlea

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D48609

llvm-svn: 335751

Author: kuhar

llvm/lib/Analysis/AliasSetTracker.cpp

@@ -639,8 +639,12 @@ void AliasSet::print(raw_ostream &OS) const {
     OS << "\n    " << UnknownInsts.size() << " Unknown instructions: ";
     for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
       if (i) OS << ", ";
-      if (auto *I = getUnknownInst(i))
-        I->printAsOperand(OS);
+      if (auto *I = getUnknownInst(i)) {
+        if (I->hasName())
+          I->printAsOperand(OS);
+        else
+          I->print(OS);
+      }
     }
   }
   OS << "\n";