[ScopInfo] Completely remove MemoryAccesses when their parent statement is removed.

Removing a statement left its MemoryAccesses in some lists and maps of
the SCoP.  Which lists depends on at which phase of the SCoP
construction the statement is deleted.  Follow-up passes could still see
the already deleted MemoryAccesses by iterating through these
lists/maps, resulting in an access violation.

When removing a ScopStmt, also remove all its MemoryAccesses by using
the same mechnism that removes a MemoryAccess.

llvm-svn: 329640

1 files changed, 18 insertions, 10 deletions

diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 81edb824c05..61552929f95 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1819,13 +1819,15 @@ void ScopStmt::removeMemoryAccess(MemoryAccess *MA) {
   InstructionToAccess.erase(MA->getAccessInstruction());
 }
 
-void ScopStmt::removeSingleMemoryAccess(MemoryAccess *MA) {
-  auto MAIt = std::find(MemAccs.begin(), MemAccs.end(), MA);
-  assert(MAIt != MemAccs.end());
-  MemAccs.erase(MAIt);
-
-  removeAccessData(MA);
-  Parent.removeAccessData(MA);
+void ScopStmt::removeSingleMemoryAccess(MemoryAccess *MA, bool AfterHoisting) {
+  if (AfterHoisting) {
+    auto MAIt = std::find(MemAccs.begin(), MemAccs.end(), MA);
+    assert(MAIt != MemAccs.end());
+    MemAccs.erase(MAIt);
+
+    removeAccessData(MA);
+    Parent.removeAccessData(MA);
+  }
 
   auto It = InstructionToAccess.find(MA->getAccessInstruction());
   if (It != InstructionToAccess.end()) {
@@ -3553,13 +3555,19 @@ void Scop::removeFromStmtMap(ScopStmt &Stmt) {
   }
 }
 
-void Scop::removeStmts(std::function<bool(ScopStmt &)> ShouldDelete) {
+void Scop::removeStmts(std::function<bool(ScopStmt &)> ShouldDelete,
+                       bool AfterHoisting) {
   for (auto StmtIt = Stmts.begin(), StmtEnd = Stmts.end(); StmtIt != StmtEnd;) {
     if (!ShouldDelete(*StmtIt)) {
       StmtIt++;
       continue;
     }
 
+    // Start with removing all of the statement's accesses including erasing it
+    // from all maps that are pointing to them.
+    for (auto *MA : *StmtIt)
+      StmtIt->removeSingleMemoryAccess(MA, AfterHoisting);
+
     removeFromStmtMap(*StmtIt);
     StmtIt = Stmts.erase(StmtIt);
   }
@@ -3569,7 +3577,7 @@ void Scop::removeStmtNotInDomainMap() {
   auto ShouldDelete = [this](ScopStmt &Stmt) -> bool {
     return !this->DomainMap.lookup(Stmt.getEntryBlock());
   };
-  removeStmts(ShouldDelete);
+  removeStmts(ShouldDelete, false);
 }
 
 void Scop::simplifySCoP(bool AfterHoisting) {
@@ -3592,7 +3600,7 @@ void Scop::simplifySCoP(bool AfterHoisting) {
     return RemoveStmt;
   };
 
-  removeStmts(ShouldDelete);
+  removeStmts(ShouldDelete, AfterHoisting);
 }
 
 InvariantEquivClassTy *Scop::lookupInvariantEquivClass(Value *Val) {