diff --git a/llvm/include/llvm/Analysis/MemoryBuiltins.h b/llvm/include/llvm/Analysis/MemoryBuiltins.h
--- a/llvm/include/llvm/Analysis/MemoryBuiltins.h
+++ b/llvm/include/llvm/Analysis/MemoryBuiltins.h
@@ -76,6 +76,14 @@
                     bool LookThroughBitCast = false);
 
 /// Tests if a value is a call or invoke to a library function that
+/// allocates uninitialized memory with alignment (such as aligned_alloc).
+bool isAlignedAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+                          bool LookThroughBitCast = false);
+bool isAlignedAllocLikeFn(
+    const Value *V, function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
+    bool LookThroughBitCast = false);
+
+/// Tests if a value is a call or invoke to a library function that
 /// allocates zero-filled memory (such as calloc).
 bool isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
                     bool LookThroughBitCast = false);
diff --git a/llvm/include/llvm/Analysis/TargetLibraryInfo.def b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
--- a/llvm/include/llvm/Analysis/TargetLibraryInfo.def
+++ b/llvm/include/llvm/Analysis/TargetLibraryInfo.def
@@ -481,6 +481,9 @@
 /// long double acosl(long double x);
 TLI_DEFINE_ENUM_INTERNAL(acosl)
 TLI_DEFINE_STRING_INTERNAL("acosl")
+/// void *aligned_alloc(size_t alignment, size_t size);
+TLI_DEFINE_ENUM_INTERNAL(aligned_alloc)
+TLI_DEFINE_STRING_INTERNAL("aligned_alloc")
 /// double asin(double x);
 TLI_DEFINE_ENUM_INTERNAL(asin)
 TLI_DEFINE_STRING_INTERNAL("asin")
diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -960,7 +960,7 @@
     }
   }
 
-  // If the call is to malloc or calloc, we can assume that it doesn't
+  // If the call is malloc/calloc like, we can assume that it doesn't
   // modify any IR visible value.  This is only valid because we assume these
   // routines do not read values visible in the IR.  TODO: Consider special
   // casing realloc and strdup routines which access only their arguments as
diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -52,11 +52,12 @@
 enum AllocType : uint8_t {
   OpNewLike          = 1<<0, // allocates; never returns null
   MallocLike         = 1<<1 | OpNewLike, // allocates; may return null
-  CallocLike         = 1<<2, // allocates + bzero
-  ReallocLike        = 1<<3, // reallocates
-  StrDupLike         = 1<<4,
-  MallocOrCallocLike = MallocLike | CallocLike,
-  AllocLike          = MallocLike | CallocLike | StrDupLike,
+  AlignedAllocLike   = 1<<2, // allocates with alignment; may return null
+  CallocLike         = 1<<3, // allocates + bzero
+  ReallocLike        = 1<<4, // reallocates
+  StrDupLike         = 1<<5,
+  MallocOrCallocLike = MallocLike | CallocLike | AlignedAllocLike,
+  AllocLike          = MallocOrCallocLike | StrDupLike,
   AnyAlloc           = AllocLike | ReallocLike
 };
 
@@ -100,6 +101,7 @@
   {LibFunc_msvc_new_array_int_nothrow, {MallocLike,  2, 0,  -1}}, // new[](unsigned int, nothrow)
   {LibFunc_msvc_new_array_longlong,         {OpNewLike,   1, 0,  -1}}, // new[](unsigned long long)
   {LibFunc_msvc_new_array_longlong_nothrow, {MallocLike,  2, 0,  -1}}, // new[](unsigned long long, nothrow)
+  {LibFunc_aligned_alloc,       {AlignedAllocLike, 2, 1,  -1}},
   {LibFunc_calloc,              {CallocLike,  2, 0,   1}},
   {LibFunc_realloc,             {ReallocLike, 2, 1,  -1}},
   {LibFunc_reallocf,            {ReallocLike, 2, 1,  -1}},
@@ -266,6 +268,20 @@
 }
 
 /// Tests if a value is a call or invoke to a library function that
+/// allocates uninitialized memory with alignment (such as aligned_alloc).
+bool llvm::isAlignedAllocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
+                                bool LookThroughBitCast) {
+  return getAllocationData(V, AlignedAllocLike, TLI, LookThroughBitCast)
+      .hasValue();
+}
+bool llvm::isAlignedAllocLikeFn(
+    const Value *V, function_ref<const TargetLibraryInfo &(Function &)> GetTLI,
+    bool LookThroughBitCast) {
+  return getAllocationData(V, AlignedAllocLike, GetTLI, LookThroughBitCast)
+      .hasValue();
+}
+
+/// Tests if a value is a call or invoke to a library function that
 /// allocates zero-filled memory (such as calloc).
 bool llvm::isCallocLikeFn(const Value *V, const TargetLibraryInfo *TLI,
                           bool LookThroughBitCast) {
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -901,6 +901,8 @@
             FTy.getParamType(1)->isPointerTy());
   case LibFunc_write:
     return (NumParams == 3 && FTy.getParamType(1)->isPointerTy());
+  case LibFunc_aligned_alloc:
+    return (NumParams == 2 && FTy.getReturnType()->isPointerTy());
   case LibFunc_bcopy:
   case LibFunc_bcmp:
     return (NumParams == 3 && FTy.getParamType(0)->isPointerTy() &&
diff --git a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
--- a/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -378,6 +378,10 @@
     Changed |= setDoesNotCapture(F, 1);
     Changed |= setOnlyReadsMemory(F, 1);
     return Changed;
+  case LibFunc_aligned_alloc:
+    Changed |= setDoesNotThrow(F);
+    Changed |= setRetDoesNotAlias(F);
+    return Changed;
   case LibFunc_bcopy:
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
diff --git a/llvm/test/Transforms/DeadStoreElimination/simple.ll b/llvm/test/Transforms/DeadStoreElimination/simple.ll
--- a/llvm/test/Transforms/DeadStoreElimination/simple.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/simple.ll
@@ -259,6 +259,8 @@
 
 declare noalias i8* @malloc(i32)
 declare noalias i8* @calloc(i32, i32)
+declare noalias i8* @aligned_alloc(i32, i32)
+declare void @free(i8*)
 
 
 define void @test14(i32* %Q) {
@@ -272,6 +274,17 @@
 
 }
 
+; Dead store on an aligned_alloc: should know that %M doesn't alias with %A.
+define i32 @test14a(i8* %M, i8 %value) {
+; CHECK-LABEL: @test14a(
+; CHECK-NOT: store
+; CHECK:     ret i32 0
+;
+  %A = tail call i8* @aligned_alloc(i32 32, i32 1024)
+  store i8 %value, i8* %A
+  tail call void @free(i8* %A)
+  ret i32 0
+}
 
 ; PR8701
 
diff --git a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
--- a/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
+++ b/llvm/unittests/Analysis/TargetLibraryInfoTest.cpp
@@ -96,6 +96,7 @@
       "declare float @acoshf(float)\n"
       "declare x86_fp80 @acoshl(x86_fp80)\n"
       "declare x86_fp80 @acosl(x86_fp80)\n"
+      "declare i8* @aligned_alloc(i64, i64)\n"
       "declare double @asin(double)\n"
       "declare float @asinf(float)\n"
       "declare double @asinh(double)\n"