[fast-isel] Fallback to SelectionDAG isel if we require strict alignment for
non-halfword-aligned i16 loads/stores.
rdar://12304911

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164345 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index 045d904..af45ed7 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -1021,6 +1021,9 @@
       RC = &ARM::GPRRegClass;
       break;
     case MVT::i16:
+      if (Alignment && Alignment < 2 && !Subtarget->allowsUnalignedMem())
+        return false;
+
       if (isThumb2) {
         if (Addr.Offset < 0 && Addr.Offset > -256 && Subtarget->hasV6T2Ops())
           Opc = isZExt ? ARM::t2LDRHi8 : ARM::t2LDRSHi8;
@@ -1139,6 +1142,9 @@
       }
       break;
     case MVT::i16:
+      if (Alignment && Alignment < 2 && !Subtarget->allowsUnalignedMem())
+        return false;
+
       if (isThumb2) {
         if (Addr.Offset < 0 && Addr.Offset > -256 && Subtarget->hasV6T2Ops())
           StrOpc = ARM::t2STRHi8;