Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -514,8 +514,10 @@
       case Intrinsic::lifetime_start:
       case Intrinsic::lifetime_end:
       case Intrinsic::objectsize:
+      case Intrinsic::annotation:
       case Intrinsic::ptr_annotation:
       case Intrinsic::var_annotation:
+      case Intrinsic::experimental_widenable_condition:
         return true;
       }
 
@@ -558,12 +560,18 @@
         return true;
   }
 
+  // Don't let an assume affect itself - this would cause the problems
+  // `isEphemeralValueOf` is trying to prevent, and it would also make
+  // the loop below go out of bounds.
+  if (Inv == CxtI)
+    return false;
+
   // The context comes first, but they're both in the same block. Make sure
   // there is nothing in between that might interrupt the control flow.
   for (BasicBlock::const_iterator I =
          std::next(BasicBlock::const_iterator(CxtI)), IE(Inv);
        I != IE; ++I)
-    if (!isSafeToSpeculativelyExecute(&*I) && !isAssumeLikeIntrinsic(&*I))
+    if (!isGuaranteedToTransferExecutionToSuccessor(&*I))
       return false;
 
   return !isEphemeralValueOf(Inv, CxtI);
@@ -4268,9 +4276,7 @@
     // FIXME: This isn't aggressive enough; a call which only writes to a global
     // is guaranteed to return.
     return CS.onlyReadsMemory() || CS.onlyAccessesArgMemory() ||
-           match(I, m_Intrinsic<Intrinsic::assume>()) ||
-           match(I, m_Intrinsic<Intrinsic::sideeffect>()) ||
-           match(I, m_Intrinsic<Intrinsic::experimental_widenable_condition>());
+           isAssumeLikeIntrinsic(I);
   }
 
   // Other instructions return normally.
Index: llvm/test/Transforms/InstCombine/assume_inevitable.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/InstCombine/assume_inevitable.ll
@@ -0,0 +1,59 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Check that assume is propagated backwards through all
+; operations that are `isGuaranteedToTransferExecutionToSuccessor`
+; (it should reach the load and mark it as `align 32`).
+define i32 @assume_inevitable(i32* %a, i32* %b, i8* %c) {
+; CHECK-LABEL: @assume_inevitable
+; CHECK-DAG: load i32, i32* %a, align 32
+; CHECK-DAG: call void @llvm.assume
+; CHECK: ret i32
+entry:
+  %dummy = alloca i8, align 4
+  %m = alloca i64
+  %0 = load i32, i32* %a, align 4
+
+  ; START perform a bunch of inevitable operations
+  %loadres = load i32, i32* %b
+  %loadres2 = call i32 @llvm.annotation.i32(i32 %loadres, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i32 0, i32 0), i32 2)
+  store i32 %loadres2, i32* %a
+
+  %dummy_eq = icmp ugt i32 %loadres, 42
+  tail call void @llvm.assume(i1 %dummy_eq)
+
+  call void @llvm.lifetime.start.p0i8(i64 1, i8* %dummy)
+  %i = call {}* @llvm.invariant.start.p0i8(i64 1, i8* %dummy)
+  call void @llvm.invariant.end.p0i8({}* %i, i64 1, i8* %dummy)
+  call void @llvm.lifetime.end.p0i8(i64 1, i8* %dummy)
+
+  %m_i8 = bitcast i64* %m to i8*
+  %m_a = call i8* @llvm.ptr.annotation.p0i8(i8* %m_i8, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i32 0, i32 0), i32 2)
+  %m_x = bitcast i8* %m_a to i64*
+  %objsz = call i64 @llvm.objectsize.i64.p0i8(i8* %c, i1 false)
+  store i64 %objsz, i64* %m_x
+  ; END perform a bunch of inevitable operations
+
+  ; AND here's the assume:
+  %ptrint = ptrtoint i32* %a to i64
+  %maskedptr = and i64 %ptrint, 31
+  %maskcond = icmp eq i64 %maskedptr, 0
+  tail call void @llvm.assume(i1 %maskcond)
+
+  ret i32 %0
+}
+
+@.str = private unnamed_addr constant [4 x i8] c"sth\00", section "llvm.metadata"
+@.str1 = private unnamed_addr constant [4 x i8] c"t.c\00", section "llvm.metadata"
+
+declare i64 @llvm.objectsize.i64.p0i8(i8*, i1)
+declare i32 @llvm.annotation.i32(i32, i8*, i8*, i32)
+declare i8* @llvm.ptr.annotation.p0i8(i8*, i8*, i8*, i32)
+
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture)
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture)
+
+declare {}* @llvm.invariant.start.p0i8(i64, i8* nocapture)
+declare void @llvm.invariant.end.p0i8({}*, i64, i8* nocapture)
+declare void @llvm.assume(i1)