Index: docs/LangRef.rst
===================================================================
--- docs/LangRef.rst
+++ docs/LangRef.rst
@@ -1945,6 +1945,8 @@
     targets.
 ``a:<abi>:<pref>``
     This specifies the alignment for an object of aggregate type.
+``F<abi>``
+    This specifies the alignment for function pointers.
 ``m:<mangling>``
     If present, specifies that llvm names are mangled in the output. Symbols
     prefixed with the mangling escape character ``\01`` are passed through
Index: include/llvm/IR/DataLayout.h
===================================================================
--- include/llvm/IR/DataLayout.h
+++ include/llvm/IR/DataLayout.h
@@ -115,6 +115,7 @@
 
   unsigned AllocaAddrSpace;
   unsigned StackNaturalAlign;
+  unsigned FunctionPtrAlign;
   unsigned ProgramAddrSpace;
 
   enum ManglingModeT {
@@ -200,6 +201,7 @@
     BigEndian = DL.isBigEndian();
     AllocaAddrSpace = DL.AllocaAddrSpace;
     StackNaturalAlign = DL.StackNaturalAlign;
+    FunctionPtrAlign = DL.FunctionPtrAlign;
     ProgramAddrSpace = DL.ProgramAddrSpace;
     ManglingMode = DL.ManglingMode;
     LegalIntWidths = DL.LegalIntWidths;
@@ -255,6 +257,7 @@
   }
 
   unsigned getStackAlignment() const { return StackNaturalAlign; }
+  unsigned getFunctionPtrAlign() const { return FunctionPtrAlign; }
   unsigned getAllocaAddrSpace() const { return AllocaAddrSpace; }
 
   unsigned getProgramAddressSpace() const { return ProgramAddrSpace; }
Index: lib/IR/DataLayout.cpp
===================================================================
--- lib/IR/DataLayout.cpp
+++ lib/IR/DataLayout.cpp
@@ -184,6 +184,7 @@
   BigEndian = false;
   AllocaAddrSpace = 0;
   StackNaturalAlign = 0;
+  FunctionPtrAlign = 0;
   ProgramAddrSpace = 0;
   ManglingMode = MM_None;
   NonIntegralAddressSpaces.clear();
@@ -380,6 +381,10 @@
       StackNaturalAlign = inBytes(getInt(Tok));
       break;
     }
+    case 'F': {
+      FunctionPtrAlign = inBytes(getInt(Tok));
+      break;
+    }
     case 'P': { // Function address space.
       ProgramAddrSpace = getAddrSpace(Tok);
       break;
@@ -432,6 +437,7 @@
   bool Ret = BigEndian == Other.BigEndian &&
              AllocaAddrSpace == Other.AllocaAddrSpace &&
              StackNaturalAlign == Other.StackNaturalAlign &&
+             FunctionPtrAlign == Other.FunctionPtrAlign &&
              ProgramAddrSpace == Other.ProgramAddrSpace &&
              ManglingMode == Other.ManglingMode &&
              LegalIntWidths == Other.LegalIntWidths &&
Index: lib/IR/Value.cpp
===================================================================
--- lib/IR/Value.cpp
+++ lib/IR/Value.cpp
@@ -685,7 +685,10 @@
 
   unsigned Align = 0;
   if (auto *GO = dyn_cast<GlobalObject>(this)) {
-    Align = GO->getAlignment();
+    if (isa<Function>(GO))
+      Align = DL.getFunctionPtrAlign();
+    if (Align == 0)
+      Align = GO->getAlignment();
     if (Align == 0) {
       if (auto *GVar = dyn_cast<GlobalVariable>(GO)) {
         Type *ObjectType = GVar->getValueType();
Index: lib/Target/ARM/ARMTargetMachine.cpp
===================================================================
--- lib/Target/ARM/ARMTargetMachine.cpp
+++ lib/Target/ARM/ARMTargetMachine.cpp
@@ -140,6 +140,10 @@
   // Pointers are 32 bits and aligned to 32 bits.
   Ret += "-p:32:32";
 
+  // Function pointers are aligned to 8 bits (because the LSB stores the
+  // ARM/Thumb state).
+  Ret += "-F8";
+
   // ABIs other than APCS have 64 bit integers with natural alignment.
   if (ABI != ARMBaseTargetMachine::ARM_ABI_APCS)
     Ret += "-i64:64";
Index: test/Analysis/ValueTracking/func-ptr-lsb.ll
===================================================================
--- /dev/null
+++ test/Analysis/ValueTracking/func-ptr-lsb.ll
@@ -0,0 +1,15 @@
+; RUN: opt -instcombine -S < %s | FileCheck %s
+
+target datalayout = "e-p:32:32-n32-S64-F8"
+
+; CHECK-LABEL: @foo_ptr
+; CHECK: and
+define i32 @foo_ptr() {
+entry:
+  ret i32 and (i32 ptrtoint (void ()* @foo to i32), i32 -4)
+}
+
+define internal void @foo() align 16 {
+entry:
+  ret void
+}