Index: lib/CodeGen/CodeGenPrepare.cpp
===================================================================
--- lib/CodeGen/CodeGenPrepare.cpp
+++ lib/CodeGen/CodeGenPrepare.cpp
@@ -6926,6 +6926,14 @@
   if (InsertedInsts.count(I))
     return false;
 
+  // Drop all llvm.assume calls
+  if (match(I, m_Intrinsic<Intrinsic::assume>())) {
+    Value *Arg = I->getOperand(0);
+    I->eraseFromParent();
+    RecursivelyDeleteTriviallyDeadInstructions(Arg);
+    return true;
+  }
+
   // TODO: Move into the switch on opcode below here.
   if (PHINode *P = dyn_cast<PHINode>(I)) {
     // It is possible for very late stage optimizations (such as SimplifyCFG)
Index: test/Transforms/CodeGenPrepare/assume.ll
===================================================================
--- test/Transforms/CodeGenPrepare/assume.ll
+++ test/Transforms/CodeGenPrepare/assume.ll
@@ -0,0 +1,17 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -codegenprepare  -S %s | FileCheck %s
+
+declare i32 @foo()
+declare void @llvm.assume(i1)
+
+define void @bar() {
+; CHECK-LABEL: @bar(
+; CHECK-NEXT:    ret void
+;
+  %call = tail call i32 @foo() #0
+  %cmp = icmp eq i32 %call, 1
+  tail call void @llvm.assume(i1 %cmp)
+  ret void
+}
+
+attributes #0 = { nounwind readnone }