Revert "[BasicAA] Revert "Revert r218714 - Make better use of zext and sign informati...

[oota-llvm.git] / lib / Analysis / ScalarEvolution.cpp

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 00b485dedee50d41475ea74b47fa2abaadddf57f..d1274d78a30575aad9e8d2acbffc5c1262e6c66b 100644 (file)
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -6313,13 +6313,22 @@ ScalarEvolution::isLoopBackedgeGuardedByCond(const Loop *L,
 
   BranchInst *LoopContinuePredicate =
     dyn_cast<BranchInst>(Latch->getTerminator());
-  if (!LoopContinuePredicate ||
-      LoopContinuePredicate->isUnconditional())
-    return false;
+  if (LoopContinuePredicate && LoopContinuePredicate->isConditional() &&
+      isImpliedCond(Pred, LHS, RHS,
+                    LoopContinuePredicate->getCondition(),
+                    LoopContinuePredicate->getSuccessor(0) != L->getHeader()))
+    return true;
+
+  // Check conditions due to any @llvm.assume intrinsics.
+  for (auto &CI : AT->assumptions(F)) {
+    if (!DT->dominates(CI, Latch->getTerminator()))
+      continue;
+
+    if (isImpliedCond(Pred, LHS, RHS, CI->getArgOperand(0), false))
+      return true;
+  }
 
-  return isImpliedCond(Pred, LHS, RHS,
-                       LoopContinuePredicate->getCondition(),
-                       LoopContinuePredicate->getSuccessor(0) != L->getHeader());
+  return false;
 }
 
 /// isLoopEntryGuardedByCond - Test whether entry to the loop is protected
@@ -6353,6 +6362,15 @@ ScalarEvolution::isLoopEntryGuardedByCond(const Loop *L,
       return true;
   }
 
+  // Check conditions due to any @llvm.assume intrinsics.
+  for (auto &CI : AT->assumptions(F)) {
+    if (!DT->dominates(CI, L->getHeader()))
+      continue;
+
+    if (isImpliedCond(Pred, LHS, RHS, CI->getArgOperand(0), false))
+      return true;
+  }
+
   return false;
 }