diff --git a/lib/IR/DataLayout.cpp b/lib/IR/DataLayout.cpp
index ab90388fae3..1b9ff3922d1 100644
--- a/lib/IR/DataLayout.cpp
+++ b/lib/IR/DataLayout.cpp
@@ -378,7 +378,10 @@ void DataLayout::parseSpecifier(StringRef Desc) {
       }
       break;
     case 'S': { // Stack natural alignment.
-      StackNaturalAlign = MaybeAlign(inBytes(getInt(Tok)));
+      uint64_t Alignment = inBytes(getInt(Tok));
+      if (Alignment != 0 && !llvm::isPowerOf2_64(Alignment))
+        report_fatal_error("Alignment is neither 0 nor a power of 2");
+      StackNaturalAlign = MaybeAlign(Alignment);
       break;
     }
     case 'F': {
@@ -394,7 +397,10 @@ void DataLayout::parseSpecifier(StringRef Desc) {
                            "datalayout string");
       }
       Tok = Tok.substr(1);
-      FunctionPtrAlign = MaybeAlign(inBytes(getInt(Tok)));
+      uint64_t Alignment = inBytes(getInt(Tok));
+      if (Alignment != 0 && !llvm::isPowerOf2_64(Alignment))
+        report_fatal_error("Alignment is neither 0 nor a power of 2");
+      FunctionPtrAlign = MaybeAlign(Alignment);
       break;
     }
     case 'P': { // Function address space.
diff --git a/test/Assembler/datalayout-invalid-function-ptr-alignment.ll b/test/Assembler/datalayout-invalid-function-ptr-alignment.ll
new file mode 100644
index 00000000000..21cd6a6dc78
--- /dev/null
+++ b/test/Assembler/datalayout-invalid-function-ptr-alignment.ll
@@ -0,0 +1,5 @@
+; RUN: not llvm-as %s 2>&1 | FileCheck %s
+
+; CHECK: LLVM ERROR: Alignment is neither 0 nor a power of 2
+
+target datalayout = "Fi24"
diff --git a/test/Assembler/datalayout-invalid-stack-natural-alignment.ll b/test/Assembler/datalayout-invalid-stack-natural-alignment.ll
new file mode 100644
index 00000000000..c8d7ba62ab8
--- /dev/null
+++ b/test/Assembler/datalayout-invalid-stack-natural-alignment.ll
@@ -0,0 +1,5 @@
+; RUN: not llvm-as %s 2>&1 | FileCheck %s
+
+; CHECK: LLVM ERROR: Alignment is neither 0 nor a power of 2
+
+target datalayout = "S24"
diff --git a/test/Bitcode/invalid-functionptr-align.ll b/test/Bitcode/invalid-functionptr-align.ll
new file mode 100644
index 00000000000..4ff797a4b01
--- /dev/null
+++ b/test/Bitcode/invalid-functionptr-align.ll
@@ -0,0 +1,5 @@
+; Bitcode with invalid function pointer alignment.
+
+; RUN: not llvm-dis %s.bc -o - 2>&1 | FileCheck %s
+
+CHECK: LLVM ERROR: Alignment is neither 0 nor a power of 2
diff --git a/test/Bitcode/invalid-functionptr-align.ll.bc b/test/Bitcode/invalid-functionptr-align.ll.bc
new file mode 100644
index 00000000000..38e4ed8f110
Binary files /dev/null and b/test/Bitcode/invalid-functionptr-align.ll.bc differ