Revert "Fix PR18361: Invalidate LoopDispositions after LoopSimplify hoists things."

This commit was the source of crasher PR18384:

While deleting: label %for.cond127
An asserting value handle still pointed to this value!
UNREACHABLE executed at llvm/lib/IR/Value.cpp:671!

Reverting to get the builders green, feel free to re-land after fixing up.
(Renato has a handy isolated repro if you need it.)

This reverts commit r198478.

llvm-svn: 198503

1 files changed, 10 insertions, 17 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 1927d288d43..6d5f16ca333 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -309,7 +309,6 @@ ReprocessLoop:
       // Attempt to hoist out all instructions except for the
       // comparison and the branch.
       bool AllInvariant = true;
-      bool AnyInvariant = false;
       for (BasicBlock::iterator I = ExitingBlock->begin(); &*I != BI; ) {
         Instruction *Inst = I++;
         // Skip debug info intrinsics.
@@ -317,26 +316,12 @@ ReprocessLoop:
           continue;
         if (Inst == CI)
           continue;
-        if (!L->makeLoopInvariant(Inst, AnyInvariant,
-                                 Preheader ? Preheader->getTerminator() : 0)) {
+        if (!L->makeLoopInvariant(Inst, Changed,
+                                  Preheader ? Preheader->getTerminator() : 0)) {
           AllInvariant = false;
           break;
         }
       }
-      if (AnyInvariant) {
-        Changed = true;
-        // If any reachable control flow within this loop has changed, notify
-        // ScalarEvolution. Currently assume the parent loop doesn't change
-        // (spliting edges doesn't count). If blocks, CFG edges, or other values
-        // in the parent loop change, then we need call to forgetLoop() for the
-        // parent instead.
-        if (SE) {
-          SE->forgetLoop(L);
-          // The loop disposition of all SCEV expressions that depend on any
-          // hoisted values have also changed.
-          SE->forgetLoopDispositions(L);
-        }
-      }
       if (!AllInvariant) continue;
 
       // The block has now been cleared of all instructions except for
@@ -349,6 +334,14 @@ ReprocessLoop:
       DEBUG(dbgs() << "LoopSimplify: Eliminating exiting block "
                    << ExitingBlock->getName() << "\n");
 
+      // If any reachable control flow within this loop has changed, notify
+      // ScalarEvolution. Currently assume the parent loop doesn't change
+      // (spliting edges doesn't count). If blocks, CFG edges, or other values
+      // in the parent loop change, then we need call to forgetLoop() for the
+      // parent instead.
+      if (SE)
+        SE->forgetLoop(L);
+
       assert(pred_begin(ExitingBlock) == pred_end(ExitingBlock));
       Changed = true;
       LI->removeBlock(ExitingBlock);