Index: llvm/lib/Transforms/Scalar/GuardWidening.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/GuardWidening.cpp
+++ llvm/lib/Transforms/Scalar/GuardWidening.cpp
@@ -42,6 +42,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/GuardUtils.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/LoopPass.h"
@@ -116,6 +117,7 @@
   DominatorTree &DT;
   PostDominatorTree *PDT;
   LoopInfo &LI;
+  AssumptionCache ∾
   MemorySSAUpdater *MSSAU;
 
   /// Together, these describe the region of interest.  This might be all of
@@ -273,10 +275,10 @@
 
 public:
   explicit GuardWideningImpl(DominatorTree &DT, PostDominatorTree *PDT,
-                             LoopInfo &LI, MemorySSAUpdater *MSSAU,
-                             DomTreeNode *Root,
-                             std::function<bool(BasicBlock*)> BlockFilter)
-      : DT(DT), PDT(PDT), LI(LI), MSSAU(MSSAU), Root(Root),
+                             LoopInfo &LI, AssumptionCache &AC,
+                             MemorySSAUpdater *MSSAU, DomTreeNode *Root,
+                             std::function<bool(BasicBlock *)> BlockFilter)
+      : DT(DT), PDT(PDT), LI(LI), AC(AC), MSSAU(MSSAU), Root(Root),
         BlockFilter(BlockFilter) {}
 
   /// The entry point for this pass.
@@ -468,7 +470,7 @@
   if (!Inst || DT.dominates(Inst, Loc) || Visited.count(Inst))
     return true;
 
-  if (!isSafeToSpeculativelyExecute(Inst, Loc, nullptr, &DT) ||
+  if (!isSafeToSpeculativelyExecute(Inst, Loc, &AC, &DT) ||
       Inst->mayReadFromMemory())
     return false;
 
@@ -488,7 +490,7 @@
   if (!Inst || DT.dominates(Inst, Loc))
     return;
 
-  assert(isSafeToSpeculativelyExecute(Inst, Loc, nullptr, &DT) &&
+  assert(isSafeToSpeculativelyExecute(Inst, Loc, &AC, &DT) &&
          !Inst->mayReadFromMemory() && "Should've checked with isAvailableAt!");
 
   for (Value *Op : Inst->operands())
@@ -764,11 +766,12 @@
   auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
   auto &LI = AM.getResult<LoopAnalysis>(F);
   auto &PDT = AM.getResult<PostDominatorTreeAnalysis>(F);
+  auto &AC = AM.getResult<AssumptionAnalysis>(F);
   auto *MSSAA = AM.getCachedResult<MemorySSAAnalysis>(F);
   std::unique_ptr<MemorySSAUpdater> MSSAU;
   if (MSSAA)
     MSSAU = std::make_unique<MemorySSAUpdater>(&MSSAA->getMSSA());
-  if (!GuardWideningImpl(DT, &PDT, LI, MSSAU ? MSSAU.get() : nullptr,
+  if (!GuardWideningImpl(DT, &PDT, LI, AC, MSSAU ? MSSAU.get() : nullptr,
                          DT.getRootNode(), [](BasicBlock *) { return true; })
            .run())
     return PreservedAnalyses::all();
@@ -791,8 +794,10 @@
   std::unique_ptr<MemorySSAUpdater> MSSAU;
   if (AR.MSSA)
     MSSAU = std::make_unique<MemorySSAUpdater>(AR.MSSA);
-  if (!GuardWideningImpl(AR.DT, nullptr, AR.LI, MSSAU ? MSSAU.get() : nullptr,
-                         AR.DT.getNode(RootBB), BlockFilter).run())
+  if (!GuardWideningImpl(AR.DT, nullptr, AR.LI, AR.AC,
+                         MSSAU ? MSSAU.get() : nullptr, AR.DT.getNode(RootBB),
+                         BlockFilter)
+           .run())
     return PreservedAnalyses::all();
 
   auto PA = getLoopPassPreservedAnalyses();
@@ -814,12 +819,13 @@
       return false;
     auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
     auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+    auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
     auto &PDT = getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree();
     auto *MSSAWP = getAnalysisIfAvailable<MemorySSAWrapperPass>();
     std::unique_ptr<MemorySSAUpdater> MSSAU;
     if (MSSAWP)
       MSSAU = std::make_unique<MemorySSAUpdater>(&MSSAWP->getMSSA());
-    return GuardWideningImpl(DT, &PDT, LI, MSSAU ? MSSAU.get() : nullptr,
+    return GuardWideningImpl(DT, &PDT, LI, AC, MSSAU ? MSSAU.get() : nullptr,
                              DT.getRootNode(),
                              [](BasicBlock *) { return true; })
         .run();
@@ -848,6 +854,8 @@
       return false;
     auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
     auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+    auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(
+        *L->getHeader()->getParent());
     auto *PDTWP = getAnalysisIfAvailable<PostDominatorTreeWrapperPass>();
     auto *PDT = PDTWP ? &PDTWP->getPostDomTree() : nullptr;
     auto *MSSAWP = getAnalysisIfAvailable<MemorySSAWrapperPass>();
@@ -861,8 +869,9 @@
     auto BlockFilter = [&](BasicBlock *BB) {
       return BB == RootBB || L->contains(BB);
     };
-    return GuardWideningImpl(DT, PDT, LI, MSSAU ? MSSAU.get() : nullptr,
-                             DT.getNode(RootBB), BlockFilter).run();
+    return GuardWideningImpl(DT, PDT, LI, AC, MSSAU ? MSSAU.get() : nullptr,
+                             DT.getNode(RootBB), BlockFilter)
+        .run();
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {