Index: llvm/docs/LangRef.rst
===================================================================
--- llvm/docs/LangRef.rst
+++ llvm/docs/LangRef.rst
@@ -1196,6 +1196,9 @@
     checked or enforced by LLVM; if the parameter or return pointer is null,
     the behavior is undefined.
 
+``nopoison``
+    This indicates that the parameter or return value must not be poison.
+
 ``dereferenceable(<n>)``
     This indicates that the parameter or return pointer is dereferenceable. This
     attribute may only be applied to pointer typed parameters. A pointer that
Index: llvm/include/llvm/Bitcode/LLVMBitCodes.h
===================================================================
--- llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -643,6 +643,7 @@
   ATTR_KIND_PREALLOCATED = 65,
   ATTR_KIND_NO_MERGE = 66,
   ATTR_KIND_NULL_POINTER_IS_VALID = 67,
+  ATTR_KIND_NO_POISON = 68,
 };
 
 enum ComdatSelectionKindCodes {
Index: llvm/include/llvm/IR/Argument.h
===================================================================
--- llvm/include/llvm/IR/Argument.h
+++ llvm/include/llvm/IR/Argument.h
@@ -54,6 +54,9 @@
   /// addrspace(0).
   bool hasNonNullAttr() const;
 
+  /// Return true if this argument is not poison
+  bool hasNoPoisonAttr() const;
+
   /// If this argument has the dereferenceable attribute, return the number of
   /// bytes known to be dereferenceable. Otherwise, zero is returned.
   uint64_t getDereferenceableBytes() const;
Index: llvm/include/llvm/IR/Attributes.td
===================================================================
--- llvm/include/llvm/IR/Attributes.td
+++ llvm/include/llvm/IR/Attributes.td
@@ -151,6 +151,9 @@
 /// Return value is always equal to this argument.
 def Returned : EnumAttr<"returned">;
 
+/// Variable is known to be not poison
+def NoPoison : EnumAttr<"nopoison">;
+
 /// Parameter is required to be a trivial constant.
 def ImmArg : EnumAttr<"immarg">;
 
Index: llvm/lib/AsmParser/LLLexer.cpp
===================================================================
--- llvm/lib/AsmParser/LLLexer.cpp
+++ llvm/lib/AsmParser/LLLexer.cpp
@@ -656,6 +656,7 @@
   KEYWORD(nofree);
   KEYWORD(noimplicitfloat);
   KEYWORD(noinline);
+  KEYWORD(nopoison);
   KEYWORD(norecurse);
   KEYWORD(nonlazybind);
   KEYWORD(nomerge);
Index: llvm/lib/AsmParser/LLParser.cpp
===================================================================
--- llvm/lib/AsmParser/LLParser.cpp
+++ llvm/lib/AsmParser/LLParser.cpp
@@ -1376,6 +1376,7 @@
     case lltok::kw_noalias:
     case lltok::kw_nocapture:
     case lltok::kw_nonnull:
+    case lltok::kw_nopoison:
     case lltok::kw_returned:
     case lltok::kw_sret:
     case lltok::kw_swifterror:
@@ -1681,6 +1682,7 @@
     case lltok::kw_nocapture:       B.addAttribute(Attribute::NoCapture); break;
     case lltok::kw_nofree:          B.addAttribute(Attribute::NoFree); break;
     case lltok::kw_nonnull:         B.addAttribute(Attribute::NonNull); break;
+    case lltok::kw_nopoison:        B.addAttribute(Attribute::NoPoison); break;
     case lltok::kw_readnone:        B.addAttribute(Attribute::ReadNone); break;
     case lltok::kw_readonly:        B.addAttribute(Attribute::ReadOnly); break;
     case lltok::kw_returned:        B.addAttribute(Attribute::Returned); break;
@@ -1775,6 +1777,7 @@
     case lltok::kw_inreg:           B.addAttribute(Attribute::InReg); break;
     case lltok::kw_noalias:         B.addAttribute(Attribute::NoAlias); break;
     case lltok::kw_nonnull:         B.addAttribute(Attribute::NonNull); break;
+    case lltok::kw_nopoison:        B.addAttribute(Attribute::NoPoison); break;
     case lltok::kw_signext:         B.addAttribute(Attribute::SExt); break;
     case lltok::kw_zeroext:         B.addAttribute(Attribute::ZExt); break;
 
Index: llvm/lib/AsmParser/LLToken.h
===================================================================
--- llvm/lib/AsmParser/LLToken.h
+++ llvm/lib/AsmParser/LLToken.h
@@ -206,6 +206,7 @@
   kw_nonlazybind,
   kw_nomerge,
   kw_nonnull,
+  kw_nopoison,
   kw_noredzone,
   kw_noreturn,
   kw_nosync,
Index: llvm/lib/Bitcode/Reader/BitcodeReader.cpp
===================================================================
--- llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -1532,6 +1532,8 @@
     return Attribute::SanitizeMemTag;
   case bitc::ATTR_KIND_PREALLOCATED:
     return Attribute::Preallocated;
+  case bitc::ATTR_KIND_NO_POISON:
+    return Attribute::NoPoison;
   }
 }
 
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -731,6 +731,8 @@
     return bitc::ATTR_KIND_SANITIZE_MEMTAG;
   case Attribute::Preallocated:
     return bitc::ATTR_KIND_PREALLOCATED;
+  case Attribute::NoPoison:
+    return bitc::ATTR_KIND_NO_POISON;
   case Attribute::EndAttrKinds:
     llvm_unreachable("Can not encode end-attribute kinds marker.");
   case Attribute::None:
Index: llvm/lib/IR/Attributes.cpp
===================================================================
--- llvm/lib/IR/Attributes.cpp
+++ llvm/lib/IR/Attributes.cpp
@@ -379,6 +379,8 @@
     return "nomerge";
   if (hasAttribute(Attribute::NonNull))
     return "nonnull";
+  if (hasAttribute(Attribute::NoPoison))
+    return "nopoison";
   if (hasAttribute(Attribute::NoRedZone))
     return "noredzone";
   if (hasAttribute(Attribute::NoReturn))
Index: llvm/lib/IR/Function.cpp
===================================================================
--- llvm/lib/IR/Function.cpp
+++ llvm/lib/IR/Function.cpp
@@ -96,6 +96,10 @@
   return false;
 }
 
+bool Argument::hasNoPoisonAttr() const {
+  return hasAttribute(Attribute::NoPoison);
+}
+
 bool Argument::hasByValAttr() const {
   if (!getType()->isPointerTy()) return false;
   return hasAttribute(Attribute::ByVal);
Index: llvm/test/Bitcode/attributes.ll
===================================================================
--- llvm/test/Bitcode/attributes.ll
+++ llvm/test/Bitcode/attributes.ll
@@ -386,6 +386,12 @@
   ret void;
 }
 
+; CHECK: define nopoison i32 @f66(i32 nopoison %a)
+define nopoison i32 @f66(i32 nopoison %a)
+{
+  ret i32 %a
+} 
+
 ; CHECK: attributes #0 = { noreturn }
 ; CHECK: attributes #1 = { nounwind }
 ; CHECK: attributes #2 = { readnone }