Add "unknown" results for memdep, which mean "I don't know whether a dependence for the given instruction exists in the given block". This cleans up all the existing hacks in memdep which represent this concept by returning clobber with various unrelated instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133031 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 19 insertions, 10 deletions

diff --git a/lib/Analysis/MemDepPrinter.cpp b/lib/Analysis/MemDepPrinter.cpp
index 64d215c37c..2283db0bc4 100644
--- a/lib/Analysis/MemDepPrinter.cpp
+++ b/lib/Analysis/MemDepPrinter.cpp
@@ -79,8 +79,8 @@ bool MemDepPrinter::runOnFunction(Function &F) {
 
     MemDepResult Res = MDA.getDependency(Inst);
     if (!Res.isNonLocal()) {
-      assert(Res.isClobber() != Res.isDef() &&
-             "Local dep should be def or clobber!");
+      assert((Res.isUnknown() || Res.isClobber() || Res.isDef()) &&
+              "Local dep should be unknown, def or clobber!");
       Deps[Inst].insert(std::make_pair(InstAndClobberFlag(Res.getInst(),
                                                           Res.isClobber()),
                                        static_cast<BasicBlock *>(0)));
@@ -92,8 +92,9 @@ bool MemDepPrinter::runOnFunction(Function &F) {
       for (MemoryDependenceAnalysis::NonLocalDepInfo::const_iterator
            I = NLDI.begin(), E = NLDI.end(); I != E; ++I) {
         const MemDepResult &Res = I->getResult();
-        assert(Res.isClobber() != Res.isDef() &&
-               "Resolved non-local call dep should be def or clobber!");
+        assert((Res.isUnknown() || Res.isClobber() || Res.isDef()) &&
+                "Resolved non-local call dep should be unknown, def or "
+                "clobber!");
         InstDeps.insert(std::make_pair(InstAndClobberFlag(Res.getInst(),
                                                           Res.isClobber()),
                                        I->getBB()));
@@ -148,16 +149,24 @@ void MemDepPrinter::print(raw_ostream &OS, const Module *M) const {
       bool isClobber = I->first.getInt();
       const BasicBlock *DepBB = I->second;
 
-      OS << "    " << (isClobber ? "Clobber" : "    Def");
+      OS << "    ";
+      if (!DepInst)
+        OS << "Unknown";
+      else if (isClobber)
+        OS << "Clobber";
+      else
+        OS << "    Def";
       if (DepBB) {
         OS << " in block ";
         WriteAsOperand(OS, DepBB, /*PrintType=*/false, M);
       }
-      OS << " from: ";
-      if (DepInst == Inst)
-        OS << "<unspecified>";
-      else
-        DepInst->print(OS);
+      if (DepInst) {
+        OS << " from: ";
+        if (DepInst == Inst)
+          OS << "<unspecified>";
+        else
+          DepInst->print(OS);
+      }
       OS << "\n";
     }