[mlir][llvm] Use tablegen for enum conversion.

[gysit]

Summary

The revision uses tablegen to convert multiple atomic and comparison
related enums automatically rather than using hand coded functions
in the import and export from and to LLVM IR.

The revision also adds additional binary operation cases to the
AtomicBinOp enum that have not been supported till now. It also
introduces the possibility to define unsupported enum cases that exist
only in LLVM IR and that are not imported into MLIR. These unsupported
cases are helpful to handle sentinel values such as BAD_BINOP that
LLVM commonly uses to terminate its enums.

[Dinistro]

I added one comment regarding naming but the rest LGTM! It's nice to see this conversion functions gone, especially as some of them did not cover everything.

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

327

"sentinels" might be misleading here. These are unsupported cases and do not necessarily correspond to sentinel values in the original LLVM enum. Change to something like unsupportedCases?

[gysit]

Address review comment.

mlir/include/mlir/Dialect/LLVMIR/LLVMEnums.td

def AsmATTOrIntel : LLVM_EnumAttr<
   /*list<LLVM_EnumAttrCase> cases=*/[AsmATT, AsmIntel]> {
   let cppNamespace = "::mlir::LLVM";
 }
 
 //===----------------------------------------------------------------------===//
 // Atomic Operations
 //===----------------------------------------------------------------------===//
 
-def AtomicBinOpXchg : I64EnumAttrCase<"xchg", 0>;
-def AtomicBinOpAdd  : I64EnumAttrCase<"add", 1>;
-def AtomicBinOpSub  : I64EnumAttrCase<"sub", 2>;
-def AtomicBinOpAnd  : I64EnumAttrCase<"_and", 3>;
-def AtomicBinOpNand : I64EnumAttrCase<"nand", 4>;
-def AtomicBinOpOr   : I64EnumAttrCase<"_or", 5>;
-def AtomicBinOpXor  : I64EnumAttrCase<"_xor", 6>;
-def AtomicBinOpMax  : I64EnumAttrCase<"max", 7>;
-def AtomicBinOpMin  : I64EnumAttrCase<"min", 8>;
-def AtomicBinOpUMax : I64EnumAttrCase<"umax", 9>;
-def AtomicBinOpUMin : I64EnumAttrCase<"umin", 10>;
-def AtomicBinOpFAdd : I64EnumAttrCase<"fadd", 11>;
-def AtomicBinOpFSub : I64EnumAttrCase<"fsub", 12>;
-def AtomicBinOp : I64EnumAttr<
+def AtomicBinOpXchg : LLVM_EnumAttrCase<"xchg", "xchg", "Xchg", 0>;
+def AtomicBinOpAdd  : LLVM_EnumAttrCase<"add", "add", "Add", 1>;
+def AtomicBinOpSub  : LLVM_EnumAttrCase<"sub", "sub", "Sub", 2>;
+def AtomicBinOpAnd  : LLVM_EnumAttrCase<"_and", "_and", "And", 3>;
+def AtomicBinOpNand : LLVM_EnumAttrCase<"nand", "nand", "Nand", 4>;
+def AtomicBinOpOr   : LLVM_EnumAttrCase<"_or", "_or", "Or", 5>;
+def AtomicBinOpXor  : LLVM_EnumAttrCase<"_xor", "_xor", "Xor", 6>;
+def AtomicBinOpMax  : LLVM_EnumAttrCase<"max", "max", "Max", 7>;
+def AtomicBinOpMin  : LLVM_EnumAttrCase<"min", "min", "Min", 8>;
+def AtomicBinOpUMax : LLVM_EnumAttrCase<"umax", "umax", "UMax", 9>;
+def AtomicBinOpUMin : LLVM_EnumAttrCase<"umin", "umin", "UMin", 10>;
+def AtomicBinOpFAdd : LLVM_EnumAttrCase<"fadd", "fadd", "FAdd", 11>;
+def AtomicBinOpFSub : LLVM_EnumAttrCase<"fsub", "fsub", "FSub", 12>;
+def AtomicBinOpFMax : LLVM_EnumAttrCase<"fmax", "fmax", "FMax", 13>;
+def AtomicBinOpFMin : LLVM_EnumAttrCase<"fmin", "fmin", "FMin", 14>;
+def AtomicBinOpUIncWrap : LLVM_EnumAttrCase<"uinc_wrap",
+                                            "uinc_wrap", "UIncWrap", 15>;
+def AtomicBinOpUDecWrap : LLVM_EnumAttrCase<"udec_wrap",
+                                            "udec_wrap", "UDecWrap", 16>;
+
+// Sentinel case that terminates the LLVM enum.
+def AtomicBadBinOp : LLVM_EnumAttrCase<"", "", "BAD_BINOP", 0>;
+
+def AtomicBinOp : LLVM_EnumAttr<
     "AtomicBinOp",
+    "::llvm::AtomicRMWInst::BinOp",
     "llvm.atomicrmw binary operations",
     [AtomicBinOpXchg, AtomicBinOpAdd, AtomicBinOpSub, AtomicBinOpAnd,
      AtomicBinOpNand, AtomicBinOpOr, AtomicBinOpXor, AtomicBinOpMax,
      AtomicBinOpMin, AtomicBinOpUMax, AtomicBinOpUMin, AtomicBinOpFAdd,
-     AtomicBinOpFSub]> {
+     AtomicBinOpFSub, AtomicBinOpFMax, AtomicBinOpFMin, AtomicBinOpUIncWrap,
+     AtomicBinOpUDecWrap],
+    [AtomicBadBinOp]> {
   let cppNamespace = "::mlir::LLVM";
 }
 
-def AtomicOrderingNotAtomic              : I64EnumAttrCase<"not_atomic", 0>;
-def AtomicOrderingUnordered              : I64EnumAttrCase<"unordered", 1>;
-def AtomicOrderingMonotonic              : I64EnumAttrCase<"monotonic", 2>;
-def AtomicOrderingAcquire                : I64EnumAttrCase<"acquire", 4>;
-def AtomicOrderingRelease                : I64EnumAttrCase<"release", 5>;
-def AtomicOrderingAcquireRelease         : I64EnumAttrCase<"acq_rel", 6>;
-def AtomicOrderingSequentiallyConsistent : I64EnumAttrCase<"seq_cst", 7>;
-def AtomicOrdering : I64EnumAttr<
+def AtomicOrderingNotAtomic : LLVM_EnumAttrCase<"not_atomic",
+                                                "not_atomic", "NotAtomic", 0>;
+def AtomicOrderingUnordered : LLVM_EnumAttrCase<"unordered",
+                                                "unordered", "Unordered", 1>;
+def AtomicOrderingMonotonic : LLVM_EnumAttrCase<"monotonic",
+                                                "monotonic", "Monotonic", 2>;
+def AtomicOrderingAcquire   : LLVM_EnumAttrCase<"acquire",
+                                                "acquire", "Acquire", 4>;
+def AtomicOrderingRelease   : LLVM_EnumAttrCase<"release",
+                                                "release", "Release", 5>;
+def AtomicOrderingAcquireRelease :
+      LLVM_EnumAttrCase<"acq_rel", "acq_rel", "AcquireRelease", 6>;
+def AtomicOrderingSequentiallyConsistent :
+      LLVM_EnumAttrCase<"seq_cst", "seq_cst", "SequentiallyConsistent", 7>;
+def AtomicOrdering : LLVM_EnumAttr<
     "AtomicOrdering",
+    "::llvm::AtomicOrdering",
     "Atomic ordering for LLVM's memory model",
     [AtomicOrderingNotAtomic, AtomicOrderingUnordered, AtomicOrderingMonotonic,
      AtomicOrderingAcquire, AtomicOrderingRelease, AtomicOrderingAcquireRelease,
-     AtomicOrderingSequentiallyConsistent]> {
+     AtomicOrderingSequentiallyConsistent
+    ]> {
   let cppNamespace = "::mlir::LLVM";
 }
 
 //===----------------------------------------------------------------------===//
 // CallingConvention
 //===----------------------------------------------------------------------===//
 
 // These values must match llvm::CallingConv ones.
def FastmathFlags : I32BitEnumAttr<
      FMFreassoc, FMFfast]> {
   let separator = ", ";
   let cppNamespace = "::mlir::LLVM";
   let genSpecializedAttr = 0;
   let printBitEnumPrimaryGroups = 1;
 }
 
 //===----------------------------------------------------------------------===//
-// FCmp Predicates
+// FCmp and ICmp Predicates
 //===----------------------------------------------------------------------===//
 
-// Predicate for float comparisons
-def FCmpPredicateFALSE  : I64EnumAttrCase<"_false", 0>;
-def FCmpPredicateOEQ    : I64EnumAttrCase<"oeq", 1>;
-def FCmpPredicateOGT    : I64EnumAttrCase<"ogt", 2>;
-def FCmpPredicateOGE    : I64EnumAttrCase<"oge", 3>;
-def FCmpPredicateOLT    : I64EnumAttrCase<"olt", 4>;
-def FCmpPredicateOLE    : I64EnumAttrCase<"ole", 5>;
-def FCmpPredicateONE    : I64EnumAttrCase<"one", 6>;
-def FCmpPredicateORD    : I64EnumAttrCase<"ord", 7>;
-def FCmpPredicateUEQ    : I64EnumAttrCase<"ueq", 8>;
-def FCmpPredicateUGT    : I64EnumAttrCase<"ugt", 9>;
-def FCmpPredicateUGE    : I64EnumAttrCase<"uge", 10>;
-def FCmpPredicateULT    : I64EnumAttrCase<"ult", 11>;
-def FCmpPredicateULE    : I64EnumAttrCase<"ule", 12>;
-def FCmpPredicateUNE    : I64EnumAttrCase<"une", 13>;
-def FCmpPredicateUNO    : I64EnumAttrCase<"uno", 14>;
-def FCmpPredicateTRUE   : I64EnumAttrCase<"_true", 15>;
-
-def FCmpPredicate : I64EnumAttr<
+// Predicates for float comparisons
+def FCmpPredicateFALSE : LLVM_EnumAttrCase<"_false", "_false", "FCMP_FALSE", 0>;
+def FCmpPredicateOEQ   : LLVM_EnumAttrCase<"oeq", "oeq", "FCMP_OEQ", 1>;
+def FCmpPredicateOGT   : LLVM_EnumAttrCase<"ogt", "ogt", "FCMP_OGT", 2>;
+def FCmpPredicateOGE   : LLVM_EnumAttrCase<"oge", "oge", "FCMP_OGE", 3>;
+def FCmpPredicateOLT   : LLVM_EnumAttrCase<"olt", "olt", "FCMP_OLT", 4>;
+def FCmpPredicateOLE   : LLVM_EnumAttrCase<"ole", "ole", "FCMP_OLE", 5>;
+def FCmpPredicateONE   : LLVM_EnumAttrCase<"one", "one", "FCMP_ONE", 6>;
+def FCmpPredicateORD   : LLVM_EnumAttrCase<"ord", "ord", "FCMP_ORD", 7>;
+def FCmpPredicateUEQ   : LLVM_EnumAttrCase<"ueq", "ueq", "FCMP_UEQ", 8>;
+def FCmpPredicateUGT   : LLVM_EnumAttrCase<"ugt", "ugt", "FCMP_UGT", 9>;
+def FCmpPredicateUGE   : LLVM_EnumAttrCase<"uge", "uge", "FCMP_UGE", 10>;
+def FCmpPredicateULT   : LLVM_EnumAttrCase<"ult", "ult", "FCMP_ULT", 11>;
+def FCmpPredicateULE   : LLVM_EnumAttrCase<"ule", "ule", "FCMP_ULE", 12>;
+def FCmpPredicateUNE   : LLVM_EnumAttrCase<"une", "une", "FCMP_UNE", 13>;
+def FCmpPredicateUNO   : LLVM_EnumAttrCase<"uno", "uno", "FCMP_UNO", 14>;
+def FCmpPredicateTRUE  : LLVM_EnumAttrCase<"_true", "_true", "FCMP_TRUE", 15>;
+
+// Predicates for integer comparisons.
+def ICmpPredicateEQ  : LLVM_EnumAttrCase<"eq", "eq", "ICMP_EQ", 0>;
+def ICmpPredicateNE  : LLVM_EnumAttrCase<"ne", "ne", "ICMP_NE", 1>;
+def ICmpPredicateSLT : LLVM_EnumAttrCase<"slt", "slt", "ICMP_SLT", 2>;
+def ICmpPredicateSLE : LLVM_EnumAttrCase<"sle", "sle", "ICMP_SLE", 3>;
+def ICmpPredicateSGT : LLVM_EnumAttrCase<"sgt", "sgt", "ICMP_SGT", 4>;
+def ICmpPredicateSGE : LLVM_EnumAttrCase<"sge", "sge", "ICMP_SGE", 5>;
+def ICmpPredicateULT : LLVM_EnumAttrCase<"ult", "ult", "ICMP_ULT", 6>;
+def ICmpPredicateULE : LLVM_EnumAttrCase<"ule", "ule", "ICMP_ULE", 7>;
+def ICmpPredicateUGT : LLVM_EnumAttrCase<"ugt", "ugt", "ICMP_UGT", 8>;
+def ICmpPredicateUGE : LLVM_EnumAttrCase<"uge", "uge", "ICMP_UGE", 9>;
+
+// Sentinel cases that terminate the float and integer LLVM enum subranges.
+def ICmpPredicateBad : LLVM_EnumAttrCase<"", "", "BAD_ICMP_PREDICATE", 0>;
+def FCmpPredicateBad : LLVM_EnumAttrCase<"", "", "BAD_FCMP_PREDICATE", 0>;
+
+// LLVM's predicate enum contains the floating-point and integer comparison
+// cases, while the LLVM dialect uses two separate enums. The floating-point
+// predicate enum thus uses the integer comparison cases as sentinels and
+// vice versa.
+def FCmpPredicate : LLVM_EnumAttr<
     "FCmpPredicate",
+    "::llvm::CmpInst::Predicate",
     "llvm.fcmp comparison predicate",
     [FCmpPredicateFALSE, FCmpPredicateOEQ, FCmpPredicateOGT, FCmpPredicateOGE,
      FCmpPredicateOLT, FCmpPredicateOLE, FCmpPredicateONE, FCmpPredicateORD,
      FCmpPredicateUEQ, FCmpPredicateUGT, FCmpPredicateUGE, FCmpPredicateULT,
-     FCmpPredicateULE, FCmpPredicateUNE, FCmpPredicateUNO, FCmpPredicateTRUE
+     FCmpPredicateULE, FCmpPredicateUNE, FCmpPredicateUNO, FCmpPredicateTRUE],
+    [ICmpPredicateEQ, ICmpPredicateNE, ICmpPredicateSLT, ICmpPredicateSLE,
+     ICmpPredicateSGT, ICmpPredicateSGE, ICmpPredicateULT, ICmpPredicateULE,
+     ICmpPredicateUGT, ICmpPredicateUGE, FCmpPredicateBad, ICmpPredicateBad
     ]> {
   let cppNamespace = "::mlir::LLVM";
 }
 
-//===----------------------------------------------------------------------===//
-// ICmp Predicates
-//===----------------------------------------------------------------------===//
-
-// Predicate for integer comparisons.
-def ICmpPredicateEQ  : I64EnumAttrCase<"eq", 0>;
-def ICmpPredicateNE  : I64EnumAttrCase<"ne", 1>;
-def ICmpPredicateSLT : I64EnumAttrCase<"slt", 2>;
-def ICmpPredicateSLE : I64EnumAttrCase<"sle", 3>;
-def ICmpPredicateSGT : I64EnumAttrCase<"sgt", 4>;
-def ICmpPredicateSGE : I64EnumAttrCase<"sge", 5>;
-def ICmpPredicateULT : I64EnumAttrCase<"ult", 6>;
-def ICmpPredicateULE : I64EnumAttrCase<"ule", 7>;
-def ICmpPredicateUGT : I64EnumAttrCase<"ugt", 8>;
-def ICmpPredicateUGE : I64EnumAttrCase<"uge", 9>;
-def ICmpPredicate : I64EnumAttr<
+def ICmpPredicate : LLVM_EnumAttr<
     "ICmpPredicate",
-    "llvm.icmp comparison predicate",
+    "::llvm::CmpInst::Predicate",
+    "lvm.icmp comparison predicate",
     [ICmpPredicateEQ, ICmpPredicateNE, ICmpPredicateSLT, ICmpPredicateSLE,
      ICmpPredicateSGT, ICmpPredicateSGE, ICmpPredicateULT, ICmpPredicateULE,
-     ICmpPredicateUGT, ICmpPredicateUGE]> {
+     ICmpPredicateUGT, ICmpPredicateUGE],
+    [FCmpPredicateFALSE, FCmpPredicateOEQ, FCmpPredicateOGT, FCmpPredicateOGE,
+     FCmpPredicateOLT, FCmpPredicateOLE, FCmpPredicateONE, FCmpPredicateORD,
+     FCmpPredicateUEQ, FCmpPredicateUGT, FCmpPredicateUGE, FCmpPredicateULT,
+     FCmpPredicateULE, FCmpPredicateUNE, FCmpPredicateUNO, FCmpPredicateTRUE,
+     FCmpPredicateBad, ICmpPredicateBad
+    ]> {
   let cppNamespace = "::mlir::LLVM";
 }
 
 //===----------------------------------------------------------------------===//
 // Linkage
 //===----------------------------------------------------------------------===//
 
 // Linkage attribute is used on functions and globals. The order follows that of

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

 }
 
 // LLVM enum attribute backed by I64Attr with string representation
 // corresponding to what is visible in the textual IR form.
 // The parameters are as follows:
 //   - `name`: name of the C++ enum class in MLIR API;
 //   - `llvmName`: name of the C++ enum in LLVM API;
 //   - `description`: textual description for documentation purposes;
-//   - `cases`: list of enum cases.
+//   - `cases`: list of enum cases;
+//   - `sentinels`: optional list of enum cases used as sentinels.
 // For example, `LLVM_EnumAttr<Linkage, "::llvm::GlobalValue::LinkageTypes`
 // produces `mlir::LLVM::Linkage` enum class in MLIR API that corresponds to (a
 // subset of) values in the `llvm::GlobalValue::LinkageTypes` in LLVM API.
+// Any cases specified in the sentinels list trigger an error during the
+// import from LLVM IR and are not part of the generated MLIR enum. They can be
+// used to handle sentinels such as `llvm::AtomicRMWInst::BinOp::BAD_BINOP`
+// that LLVM commonly uses to terminate its enums. Importing these sentinel
+// values would introduce artifical error cases that require extra handling.
 class LLVM_EnumAttr<string name, string llvmName, string description,
-                    list<LLVM_EnumAttrCase> cases> :
+                    list<LLVM_EnumAttrCase> cases,
+                    list<LLVM_EnumAttrCase> sentinels = []> :
     I64EnumAttr<name, description, cases> {
 
+  // List of all cases used as sentinels in LLVM.
+  list<LLVM_EnumAttrCase> llvmSentinels = sentinels;
+
   // The equivalent enum class name in LLVM.
   string llvmClassName = llvmName;
 }
 
 // LLVM_CEnumAttr is functionally identical to LLVM_EnumAttr, but to be used for
 // non-class enums.
 class LLVM_CEnumAttr<string name, string llvmNS, string description,
       list<LLVM_EnumAttrCase> cases> :

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

def LLVM_ICmpOp : LLVM_ArithmeticCmpOp<"icmp", [Pure]> {
   let arguments = (ins ICmpPredicate:$predicate,
                    AnyTypeOf<[LLVM_ScalarOrVectorOf<AnyInteger>,
                               LLVM_ScalarOrVectorOf<LLVM_AnyPointer>]>:$lhs,
                    AnyTypeOf<[LLVM_ScalarOrVectorOf<AnyInteger>,
                               LLVM_ScalarOrVectorOf<LLVM_AnyPointer>]>:$rhs);
   let hasCustomAssemblyFormat = 1;
   string llvmInstName = "ICmp";
   string llvmBuilder = [{
-    $res = builder.CreateICmp(getLLVMCmpPredicate($predicate), $lhs, $rhs);
+    $res = builder.CreateICmp(
+            convertICmpPredicateToLLVM($predicate), $lhs, $rhs);
   }];
   string mlirBuilder = [{
     auto *iCmpInst = cast<llvm::ICmpInst>(inst);
-    $res = $_builder.create<$_qualCppClassName>(
-      $_location, getICmpPredicate(iCmpInst->getPredicate()), $lhs, $rhs);
+    $res = $_builder.create<$_qualCppClassName>($_location,
+            convertICmpPredicateFromLLVM(iCmpInst->getPredicate()), $lhs, $rhs);
   }];
   // Set the $predicate index to -1 to indicate there is no matching operand
   // and decrement the following indices.
   list<int> llvmArgIndices = [-1, 0, 1];
 }
 
 // Other floating-point operations.
 def LLVM_FCmpOp : LLVM_ArithmeticCmpOp<"fcmp", [
     Pure, DeclareOpInterfaceMethods<FastmathFlagsInterface>]> {
   let arguments = (ins FCmpPredicate:$predicate,
                    LLVM_ScalarOrVectorOf<LLVM_AnyFloat>:$lhs,
                    LLVM_ScalarOrVectorOf<LLVM_AnyFloat>:$rhs,
                    DefaultValuedAttr<LLVM_FastmathFlagsAttr,
                                      "{}">:$fastmathFlags);
   let hasCustomAssemblyFormat = 1;
   string llvmInstName = "FCmp";
   string llvmBuilder = [{
-    $res = builder.CreateFCmp(getLLVMCmpPredicate($predicate), $lhs, $rhs);
+    $res = builder.CreateFCmp(convertFCmpPredicateToLLVM($predicate), $lhs, $rhs);
   }];
   string mlirBuilder = [{
     auto *fCmpInst = cast<llvm::FCmpInst>(inst);
     auto op = $_builder.create<$_qualCppClassName>(
-      $_location, getFCmpPredicate(fCmpInst->getPredicate()), $lhs, $rhs);
+      $_location, convertFCmpPredicateFromLLVM(fCmpInst->getPredicate()), $lhs, $rhs);
     moduleImport.setFastmathFlagsAttr(inst, op);
     $res = op;
   }];
   // Set the $predicate index to -1 to indicate there is no matching operand
   // and decrement the following indices.
   list<int> llvmArgIndices = [-1, 0, 1, 2];
 }
 
def LLVM_AtomicRMWOp : LLVM_Op<"atomicrmw", [
   let results = (outs LLVM_AtomicRMWType:$res);
   let hasVerifier = 1;
   let assemblyFormat = [{
     $bin_op $ptr `,` $val $ordering
     attr-dict `:` qualified(type($ptr)) `,` type($val)
   }];
   string llvmInstName = "AtomicRMW";
   string llvmBuilder = [{
-    $res = builder.CreateAtomicRMW(getLLVMAtomicBinOp($bin_op), $ptr, $val,
-                                   llvm::MaybeAlign(),
-                                   getLLVMAtomicOrdering($ordering));
+    $res = builder.CreateAtomicRMW(
+        convertAtomicBinOpToLLVM($bin_op), $ptr, $val, llvm::MaybeAlign(),
+        convertAtomicOrderingToLLVM($ordering));
   }];
   string mlirBuilder = [{
     auto *atomicInst = cast<llvm::AtomicRMWInst>(inst);
     $res = $_builder.create<LLVM::AtomicRMWOp>($_location, $_resultType,
-        getLLVMAtomicBinOp(atomicInst->getOperation()), $ptr, $val,
-        getLLVMAtomicOrdering(atomicInst->getOrdering()));
+        convertAtomicBinOpFromLLVM(atomicInst->getOperation()), $ptr, $val,
+        convertAtomicOrderingFromLLVM(atomicInst->getOrdering()));
   }];
   // Only $ptr and $val are llvm instruction operands.
   list<int> llvmArgIndices = [-1, 0, 1, -1];
 }
 
 def LLVM_AtomicCmpXchgType : AnyTypeOf<[AnyInteger, LLVM_AnyPointer]>;
 
 // FIXME: Need to add alignment attribute to MLIR cmpxchg operation.
def LLVM_AtomicCmpXchgOp : LLVM_Op<"cmpxchg", [
   let hasVerifier = 1;
   let assemblyFormat = [{
     $ptr `,` $cmp `,` $val $success_ordering $failure_ordering
     attr-dict `:` qualified(type($ptr)) `,` type($val)
   }];
   string llvmInstName = "AtomicCmpXchg";
   string llvmBuilder = [{
     $res = builder.CreateAtomicCmpXchg($ptr, $cmp, $val, llvm::MaybeAlign(),
-                   getLLVMAtomicOrdering($success_ordering),
-                   getLLVMAtomicOrdering($failure_ordering));
+                   convertAtomicOrderingToLLVM($success_ordering),
+                   convertAtomicOrderingToLLVM($failure_ordering));
   }];
   string mlirBuilder = [{
     auto *cmpXchgInst = cast<llvm::AtomicCmpXchgInst>(inst);
     $res = $_builder.create<LLVM::AtomicCmpXchgOp>(
       $_location, $_resultType, $ptr, $cmp, $val,
-      getLLVMAtomicOrdering(cmpXchgInst->getSuccessOrdering()),
-      getLLVMAtomicOrdering(cmpXchgInst->getFailureOrdering()));
+      convertAtomicOrderingFromLLVM(cmpXchgInst->getSuccessOrdering()),
+      convertAtomicOrderingFromLLVM(cmpXchgInst->getFailureOrdering()));
   }];
 }
 
 def LLVM_FenceOp : LLVM_Op<"fence"> {
   let arguments = (ins AtomicOrdering:$ordering, StrAttr:$syncscope);
   let builders = [LLVM_VoidResultTypeOpBuilder, LLVM_ZeroResultOpBuilder];
   string llvmInstName = "Fence";
   let llvmBuilder = [{
     llvm::LLVMContext &llvmContext = builder.getContext();
-    builder.CreateFence(getLLVMAtomicOrdering($ordering),
+    builder.CreateFence(convertAtomicOrderingToLLVM($ordering),
       llvmContext.getOrInsertSyncScopeID($syncscope));
   }];
   string mlirBuilder = [{
     llvm::FenceInst *fenceInst = cast<llvm::FenceInst>(inst);
     $_op = $_builder.create<LLVM::FenceOp>(
       $_location,
-      getLLVMAtomicOrdering(fenceInst->getOrdering()),
+      convertAtomicOrderingFromLLVM(fenceInst->getOrdering()),
       getLLVMSyncScope(fenceInst));
   }];
   let hasCustomAssemblyFormat = 1;
   let hasVerifier = 1;
 }
 
 def LLVM_InlineAsmOp : LLVM_Op<"inline_asm", []> {
   let description = [{

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

 //===----------------------------------------------------------------------===//
 
 LogicalResult AtomicRMWOp::verify() {
   auto ptrType = getPtr().getType().cast<LLVM::LLVMPointerType>();
   auto valType = getVal().getType();
   if (!ptrType.isOpaque() && valType != ptrType.getElementType())
     return emitOpError("expected LLVM IR element type for operand #0 to "
                        "match type for operand #1");
-  if (getBinOp() == AtomicBinOp::fadd || getBinOp() == AtomicBinOp::fsub) {
+  if (getBinOp() == AtomicBinOp::fadd || getBinOp() == AtomicBinOp::fsub ||
+      getBinOp() == AtomicBinOp::fmin || getBinOp() == AtomicBinOp::fmax) {
     if (!mlir::LLVM::isCompatibleFloatingPointType(valType))
       return emitOpError("expected LLVM IR floating point type");
   } else if (getBinOp() == AtomicBinOp::xchg) {
     auto intType = valType.dyn_cast<IntegerType>();
     unsigned intBitWidth = intType ? intType.getWidth() : 0;
     if (intBitWidth != 8 && intBitWidth != 16 && intBitWidth != 32 &&
         intBitWidth != 64 && !valType.isa<BFloat16Type>() &&
         !valType.isa<Float16Type>() && !valType.isa<Float32Type>() &&

mlir/lib/Target/LLVMIR/Dialect/LLVMIR/LLVMToLLVMIRTranslation.cpp

 #include "llvm/IR/Operator.h"
 
 using namespace mlir;
 using namespace mlir::LLVM;
 using mlir::LLVM::detail::getLLVMConstant;
 
 #include "mlir/Dialect/LLVMIR/LLVMConversionEnumsToLLVM.inc"
 
-/// Convert MLIR integer comparison predicate to LLVM IR comparison predicate.
-static llvm::CmpInst::Predicate getLLVMCmpPredicate(ICmpPredicate p) {
-  switch (p) {
-  case LLVM::ICmpPredicate::eq:
-    return llvm::CmpInst::Predicate::ICMP_EQ;
-  case LLVM::ICmpPredicate::ne:
-    return llvm::CmpInst::Predicate::ICMP_NE;
-  case LLVM::ICmpPredicate::slt:
-    return llvm::CmpInst::Predicate::ICMP_SLT;
-  case LLVM::ICmpPredicate::sle:
-    return llvm::CmpInst::Predicate::ICMP_SLE;
-  case LLVM::ICmpPredicate::sgt:
-    return llvm::CmpInst::Predicate::ICMP_SGT;
-  case LLVM::ICmpPredicate::sge:
-    return llvm::CmpInst::Predicate::ICMP_SGE;
-  case LLVM::ICmpPredicate::ult:
-    return llvm::CmpInst::Predicate::ICMP_ULT;
-  case LLVM::ICmpPredicate::ule:
-    return llvm::CmpInst::Predicate::ICMP_ULE;
-  case LLVM::ICmpPredicate::ugt:
-    return llvm::CmpInst::Predicate::ICMP_UGT;
-  case LLVM::ICmpPredicate::uge:
-    return llvm::CmpInst::Predicate::ICMP_UGE;
-  }
-  llvm_unreachable("incorrect comparison predicate");
-}
-
-static llvm::CmpInst::Predicate getLLVMCmpPredicate(FCmpPredicate p) {
-  switch (p) {
-  case LLVM::FCmpPredicate::_false:
-    return llvm::CmpInst::Predicate::FCMP_FALSE;
-  case LLVM::FCmpPredicate::oeq:
-    return llvm::CmpInst::Predicate::FCMP_OEQ;
-  case LLVM::FCmpPredicate::ogt:
-    return llvm::CmpInst::Predicate::FCMP_OGT;
-  case LLVM::FCmpPredicate::oge:
-    return llvm::CmpInst::Predicate::FCMP_OGE;
-  case LLVM::FCmpPredicate::olt:
-    return llvm::CmpInst::Predicate::FCMP_OLT;
-  case LLVM::FCmpPredicate::ole:
-    return llvm::CmpInst::Predicate::FCMP_OLE;
-  case LLVM::FCmpPredicate::one:
-    return llvm::CmpInst::Predicate::FCMP_ONE;
-  case LLVM::FCmpPredicate::ord:
-    return llvm::CmpInst::Predicate::FCMP_ORD;
-  case LLVM::FCmpPredicate::ueq:
-    return llvm::CmpInst::Predicate::FCMP_UEQ;
-  case LLVM::FCmpPredicate::ugt:
-    return llvm::CmpInst::Predicate::FCMP_UGT;
-  case LLVM::FCmpPredicate::uge:
-    return llvm::CmpInst::Predicate::FCMP_UGE;
-  case LLVM::FCmpPredicate::ult:
-    return llvm::CmpInst::Predicate::FCMP_ULT;
-  case LLVM::FCmpPredicate::ule:
-    return llvm::CmpInst::Predicate::FCMP_ULE;
-  case LLVM::FCmpPredicate::une:
-    return llvm::CmpInst::Predicate::FCMP_UNE;
-  case LLVM::FCmpPredicate::uno:
-    return llvm::CmpInst::Predicate::FCMP_UNO;
-  case LLVM::FCmpPredicate::_true:
-    return llvm::CmpInst::Predicate::FCMP_TRUE;
-  }
-  llvm_unreachable("incorrect comparison predicate");
-}
-
-static llvm::AtomicRMWInst::BinOp getLLVMAtomicBinOp(AtomicBinOp op) {
-  switch (op) {
-  case LLVM::AtomicBinOp::xchg:
-    return llvm::AtomicRMWInst::BinOp::Xchg;
-  case LLVM::AtomicBinOp::add:
-    return llvm::AtomicRMWInst::BinOp::Add;
-  case LLVM::AtomicBinOp::sub:
-    return llvm::AtomicRMWInst::BinOp::Sub;
-  case LLVM::AtomicBinOp::_and:
-    return llvm::AtomicRMWInst::BinOp::And;
-  case LLVM::AtomicBinOp::nand:
-    return llvm::AtomicRMWInst::BinOp::Nand;
-  case LLVM::AtomicBinOp::_or:
-    return llvm::AtomicRMWInst::BinOp::Or;
-  case LLVM::AtomicBinOp::_xor:
-    return llvm::AtomicRMWInst::BinOp::Xor;
-  case LLVM::AtomicBinOp::max:
-    return llvm::AtomicRMWInst::BinOp::Max;
-  case LLVM::AtomicBinOp::min:
-    return llvm::AtomicRMWInst::BinOp::Min;
-  case LLVM::AtomicBinOp::umax:
-    return llvm::AtomicRMWInst::BinOp::UMax;
-  case LLVM::AtomicBinOp::umin:
-    return llvm::AtomicRMWInst::BinOp::UMin;
-  case LLVM::AtomicBinOp::fadd:
-    return llvm::AtomicRMWInst::BinOp::FAdd;
-  case LLVM::AtomicBinOp::fsub:
-    return llvm::AtomicRMWInst::BinOp::FSub;
-  }
-  llvm_unreachable("incorrect atomic binary operator");
-}
-
-static llvm::AtomicOrdering getLLVMAtomicOrdering(AtomicOrdering ordering) {
-  switch (ordering) {
-  case LLVM::AtomicOrdering::not_atomic:
-    return llvm::AtomicOrdering::NotAtomic;
-  case LLVM::AtomicOrdering::unordered:
-    return llvm::AtomicOrdering::Unordered;
-  case LLVM::AtomicOrdering::monotonic:
-    return llvm::AtomicOrdering::Monotonic;
-  case LLVM::AtomicOrdering::acquire:
-    return llvm::AtomicOrdering::Acquire;
-  case LLVM::AtomicOrdering::release:
-    return llvm::AtomicOrdering::Release;
-  case LLVM::AtomicOrdering::acq_rel:
-    return llvm::AtomicOrdering::AcquireRelease;
-  case LLVM::AtomicOrdering::seq_cst:
-    return llvm::AtomicOrdering::SequentiallyConsistent;
-  }
-  llvm_unreachable("incorrect atomic ordering");
-}
-
 static llvm::FastMathFlags getFastmathFlags(FastmathFlagsInterface &op) {
   using llvmFMF = llvm::FastMathFlags;
   using FuncT = void (llvmFMF::*)(bool);
   const std::pair<FastmathFlags, FuncT> handlers[] = {
       // clang-format off
       {FastmathFlags::nnan,     &llvmFMF::setNoNaNs},
       {FastmathFlags::ninf,     &llvmFMF::setNoInfs},
       {FastmathFlags::nsz,      &llvmFMF::setNoSignedZeros},

mlir/lib/Target/LLVMIR/ModuleImport.cpp

case 80:
     return FloatType::getF80(&ctx);
   case 128:
     return FloatType::getF128(&ctx);
   default:
     return nullptr;
   }
 }
 
-static ICmpPredicate getICmpPredicate(llvm::CmpInst::Predicate pred) {
-  switch (pred) {
-  default:
-    llvm_unreachable("incorrect comparison predicate");
-  case llvm::CmpInst::Predicate::ICMP_EQ:
-    return LLVM::ICmpPredicate::eq;
-  case llvm::CmpInst::Predicate::ICMP_NE:
-    return LLVM::ICmpPredicate::ne;
-  case llvm::CmpInst::Predicate::ICMP_SLT:
-    return LLVM::ICmpPredicate::slt;
-  case llvm::CmpInst::Predicate::ICMP_SLE:
-    return LLVM::ICmpPredicate::sle;
-  case llvm::CmpInst::Predicate::ICMP_SGT:
-    return LLVM::ICmpPredicate::sgt;
-  case llvm::CmpInst::Predicate::ICMP_SGE:
-    return LLVM::ICmpPredicate::sge;
-  case llvm::CmpInst::Predicate::ICMP_ULT:
-    return LLVM::ICmpPredicate::ult;
-  case llvm::CmpInst::Predicate::ICMP_ULE:
-    return LLVM::ICmpPredicate::ule;
-  case llvm::CmpInst::Predicate::ICMP_UGT:
-    return LLVM::ICmpPredicate::ugt;
-  case llvm::CmpInst::Predicate::ICMP_UGE:
-    return LLVM::ICmpPredicate::uge;
-  }
-  llvm_unreachable("incorrect integer comparison predicate");
-}
-
-static FCmpPredicate getFCmpPredicate(llvm::CmpInst::Predicate pred) {
-  switch (pred) {
-  default:
-    llvm_unreachable("incorrect comparison predicate");
-  case llvm::CmpInst::Predicate::FCMP_FALSE:
-    return LLVM::FCmpPredicate::_false;
-  case llvm::CmpInst::Predicate::FCMP_TRUE:
-    return LLVM::FCmpPredicate::_true;
-  case llvm::CmpInst::Predicate::FCMP_OEQ:
-    return LLVM::FCmpPredicate::oeq;
-  case llvm::CmpInst::Predicate::FCMP_ONE:
-    return LLVM::FCmpPredicate::one;
-  case llvm::CmpInst::Predicate::FCMP_OLT:
-    return LLVM::FCmpPredicate::olt;
-  case llvm::CmpInst::Predicate::FCMP_OLE:
-    return LLVM::FCmpPredicate::ole;
-  case llvm::CmpInst::Predicate::FCMP_OGT:
-    return LLVM::FCmpPredicate::ogt;
-  case llvm::CmpInst::Predicate::FCMP_OGE:
-    return LLVM::FCmpPredicate::oge;
-  case llvm::CmpInst::Predicate::FCMP_ORD:
-    return LLVM::FCmpPredicate::ord;
-  case llvm::CmpInst::Predicate::FCMP_ULT:
-    return LLVM::FCmpPredicate::ult;
-  case llvm::CmpInst::Predicate::FCMP_ULE:
-    return LLVM::FCmpPredicate::ule;
-  case llvm::CmpInst::Predicate::FCMP_UGT:
-    return LLVM::FCmpPredicate::ugt;
-  case llvm::CmpInst::Predicate::FCMP_UGE:
-    return LLVM::FCmpPredicate::uge;
-  case llvm::CmpInst::Predicate::FCMP_UNO:
-    return LLVM::FCmpPredicate::uno;
-  case llvm::CmpInst::Predicate::FCMP_UEQ:
-    return LLVM::FCmpPredicate::ueq;
-  case llvm::CmpInst::Predicate::FCMP_UNE:
-    return LLVM::FCmpPredicate::une;
-  }
-  llvm_unreachable("incorrect floating point comparison predicate");
-}
-
-static AtomicOrdering getLLVMAtomicOrdering(llvm::AtomicOrdering ordering) {
-  switch (ordering) {
-  case llvm::AtomicOrdering::NotAtomic:
-    return LLVM::AtomicOrdering::not_atomic;
-  case llvm::AtomicOrdering::Unordered:
-    return LLVM::AtomicOrdering::unordered;
-  case llvm::AtomicOrdering::Monotonic:
-    return LLVM::AtomicOrdering::monotonic;
-  case llvm::AtomicOrdering::Acquire:
-    return LLVM::AtomicOrdering::acquire;
-  case llvm::AtomicOrdering::Release:
-    return LLVM::AtomicOrdering::release;
-  case llvm::AtomicOrdering::AcquireRelease:
-    return LLVM::AtomicOrdering::acq_rel;
-  case llvm::AtomicOrdering::SequentiallyConsistent:
-    return LLVM::AtomicOrdering::seq_cst;
-  }
-  llvm_unreachable("incorrect atomic ordering");
-}
-
-static AtomicBinOp getLLVMAtomicBinOp(llvm::AtomicRMWInst::BinOp binOp) {
-  switch (binOp) {
-  case llvm::AtomicRMWInst::Xchg:
-    return LLVM::AtomicBinOp::xchg;
-  case llvm::AtomicRMWInst::Add:
-    return LLVM::AtomicBinOp::add;
-  case llvm::AtomicRMWInst::Sub:
-    return LLVM::AtomicBinOp::sub;
-  case llvm::AtomicRMWInst::And:
-    return LLVM::AtomicBinOp::_and;
-  case llvm::AtomicRMWInst::Nand:
-    return LLVM::AtomicBinOp::nand;
-  case llvm::AtomicRMWInst::Or:
-    return LLVM::AtomicBinOp::_or;
-  case llvm::AtomicRMWInst::Xor:
-    return LLVM::AtomicBinOp::_xor;
-  case llvm::AtomicRMWInst::Max:
-    return LLVM::AtomicBinOp::max;
-  case llvm::AtomicRMWInst::Min:
-    return LLVM::AtomicBinOp::min;
-  case llvm::AtomicRMWInst::UMax:
-    return LLVM::AtomicBinOp::umax;
-  case llvm::AtomicRMWInst::UMin:
-    return LLVM::AtomicBinOp::umin;
-  case llvm::AtomicRMWInst::FAdd:
-    return LLVM::AtomicBinOp::fadd;
-  case llvm::AtomicRMWInst::FSub:
-    return LLVM::AtomicBinOp::fsub;
-  default:
-    llvm_unreachable("unsupported atomic binary operation");
-  }
-}
-
 /// Converts the sync scope identifier of `fenceInst` to the string
 /// representation necessary to build the LLVM dialect fence operation.
 static StringRef getLLVMSyncScope(llvm::FenceInst *fenceInst) {
   llvm::LLVMContext &llvmContext = fenceInst->getContext();
   SmallVector<StringRef> syncScopeNames;
   llvmContext.getSyncScopeNames(syncScopeNames);
   for (StringRef name : syncScopeNames)
     if (fenceInst->getSyncScopeID() == llvmContext.getOrInsertSyncScopeID(name))

mlir/test/Target/LLVMIR/Import/instructions.ll

define void @atomic_rmw(ptr %ptr1, i32 %val1, ptr %ptr2, float %val2) {
   ; CHECK:  llvm.atomicrmw umax %[[PTR1]], %[[VAL1]] acquire
   %10 = atomicrmw umax ptr %ptr1, i32 %val1 acquire
   ; CHECK:  llvm.atomicrmw umin %[[PTR1]], %[[VAL1]] acquire
   %11 = atomicrmw umin ptr %ptr1, i32 %val1 acquire
   ; CHECK:  llvm.atomicrmw fadd %[[PTR2]], %[[VAL2]] acquire
   %12 = atomicrmw fadd ptr %ptr2, float %val2 acquire
   ; CHECK:  llvm.atomicrmw fsub %[[PTR2]], %[[VAL2]] acquire
   %13 = atomicrmw fsub ptr %ptr2, float %val2 acquire
+  ; CHECK:  llvm.atomicrmw fmax %[[PTR2]], %[[VAL2]] acquire
+  %14 = atomicrmw fmax ptr %ptr2, float %val2 acquire
+  ; CHECK:  llvm.atomicrmw fmin %[[PTR2]], %[[VAL2]] acquire
+  %15 = atomicrmw fmin ptr %ptr2, float %val2 acquire
+  ; CHECK:  llvm.atomicrmw uinc_wrap %[[PTR1]], %[[VAL1]] acquire
+  %16 = atomicrmw uinc_wrap ptr %ptr1, i32 %val1 acquire
+  ; CHECK:  llvm.atomicrmw udec_wrap %[[PTR1]], %[[VAL1]] acquire
+  %17 = atomicrmw udec_wrap ptr %ptr1, i32 %val1 acquire
   ret void
 }
 
 ; // -----
 
 ; CHECK-LABEL: @atomic_cmpxchg
 ; CHECK-SAME:  %[[PTR1:[a-zA-Z0-9]+]]
 ; CHECK-SAME:  %[[VAL1:[a-zA-Z0-9]+]]

mlir/test/Target/LLVMIR/llvmir.mlir

 // CHECK-LABEL: @atomicrmw
 llvm.func @atomicrmw(
     %f32_ptr : !llvm.ptr<f32>, %f32 : f32,
     %i32_ptr : !llvm.ptr<i32>, %i32 : i32) {
   // CHECK: atomicrmw fadd ptr %{{.*}}, float %{{.*}} monotonic
   %0 = llvm.atomicrmw fadd %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
   // CHECK: atomicrmw fsub ptr %{{.*}}, float %{{.*}} monotonic
   %1 = llvm.atomicrmw fsub %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
+  // CHECK: atomicrmw fmax ptr %{{.*}}, float %{{.*}} monotonic
+  %2 = llvm.atomicrmw fmax %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
+  // CHECK: atomicrmw fmin ptr %{{.*}}, float %{{.*}} monotonic
+  %3 = llvm.atomicrmw fmin %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
   // CHECK: atomicrmw xchg ptr %{{.*}}, float %{{.*}} monotonic
-  %2 = llvm.atomicrmw xchg %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
+  %4 = llvm.atomicrmw xchg %f32_ptr, %f32 monotonic : !llvm.ptr<f32>, f32
   // CHECK: atomicrmw add ptr %{{.*}}, i32 %{{.*}} acquire
-  %3 = llvm.atomicrmw add %i32_ptr, %i32 acquire : !llvm.ptr<i32>, i32
+  %5 = llvm.atomicrmw add %i32_ptr, %i32 acquire : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw sub ptr %{{.*}}, i32 %{{.*}} release
-  %4 = llvm.atomicrmw sub %i32_ptr, %i32 release : !llvm.ptr<i32>, i32
+  %6 = llvm.atomicrmw sub %i32_ptr, %i32 release : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw and ptr %{{.*}}, i32 %{{.*}} acq_rel
-  %5 = llvm.atomicrmw _and %i32_ptr, %i32 acq_rel : !llvm.ptr<i32>, i32
+  %7 = llvm.atomicrmw _and %i32_ptr, %i32 acq_rel : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw nand ptr %{{.*}}, i32 %{{.*}} seq_cst
-  %6 = llvm.atomicrmw nand %i32_ptr, %i32 seq_cst : !llvm.ptr<i32>, i32
+  %8 = llvm.atomicrmw nand %i32_ptr, %i32 seq_cst : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw or ptr %{{.*}}, i32 %{{.*}} monotonic
-  %7 = llvm.atomicrmw _or %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %9 = llvm.atomicrmw _or %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw xor ptr %{{.*}}, i32 %{{.*}} monotonic
-  %8 = llvm.atomicrmw _xor %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %10 = llvm.atomicrmw _xor %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw max ptr %{{.*}}, i32 %{{.*}} monotonic
-  %9 = llvm.atomicrmw max %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %11 = llvm.atomicrmw max %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw min ptr %{{.*}}, i32 %{{.*}} monotonic
-  %10 = llvm.atomicrmw min %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %12 = llvm.atomicrmw min %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw umax ptr %{{.*}}, i32 %{{.*}} monotonic
-  %11 = llvm.atomicrmw umax %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %13 = llvm.atomicrmw umax %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   // CHECK: atomicrmw umin ptr %{{.*}}, i32 %{{.*}} monotonic
-  %12 = llvm.atomicrmw umin %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  %14 = llvm.atomicrmw umin %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  // CHECK: atomicrmw uinc_wrap ptr %{{.*}}, i32 %{{.*}} monotonic
+  %15 = llvm.atomicrmw uinc_wrap %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
+  // CHECK: atomicrmw udec_wrap ptr %{{.*}}, i32 %{{.*}} monotonic
+  %16 = llvm.atomicrmw udec_wrap %i32_ptr, %i32 monotonic : !llvm.ptr<i32>, i32
   llvm.return
 }
 
 // CHECK-LABEL: @cmpxchg
 llvm.func @cmpxchg(%ptr : !llvm.ptr<i32>, %cmp : i32, %val: i32) {
   // CHECK: cmpxchg ptr %{{.*}}, i32 %{{.*}}, i32 %{{.*}} acq_rel monotonic
   %0 = llvm.cmpxchg %ptr, %cmp, %val acq_rel monotonic : !llvm.ptr<i32>, i32
   // CHECK: %{{[0-9]+}} = extractvalue { i32, i1 } %{{[0-9]+}}, 0

mlir/tools/mlir-tblgen/LLVMIRConversionGen.cpp

public:
   std::vector<LLVMEnumAttrCase> getAllCases() const {
     std::vector<LLVMEnumAttrCase> cases;
 
     for (auto &c : tblgen::EnumAttr::getAllCases())
       cases.emplace_back(c);
 
     return cases;
   }
+
+  std::vector<LLVMEnumAttrCase> getAllSentinels() const {
+    const auto *inits = def->getValueAsListInit("llvmSentinels");
+
+    std::vector<LLVMEnumAttrCase> cases;
+    cases.reserve(inits->size());
+
+    for (const llvm::Init *init : *inits)
+      cases.emplace_back(cast<llvm::DefInit>(init));
+
+    return cases;
+  }
 };
 
 // Wraper class around a Tablegen definition of a C-style LLVM enum attribute.
 class LLVMCEnumAttr : public tblgen::EnumAttr {
 public:
   using tblgen::EnumAttr::EnumAttr;
 
   // Returns the C++ enum name for the LLVM API.
static void emitOneEnumFromConversion(const llvm::Record *record,
 
   for (const auto &enumerant : enumAttr.getAllCases()) {
     StringRef llvmEnumerant = enumerant.getLLVMEnumerant();
     StringRef cppEnumerant = enumerant.getSymbol();
     os << formatv("  case {0}::{1}:\n", llvmClass, llvmEnumerant);
     os << formatv("    return {0}::{1}::{2};\n", cppNamespace, cppClassName,
                   cppEnumerant);
   }
+  for (const auto &enumerant : enumAttr.getAllSentinels()) {
+    StringRef llvmEnumerant = enumerant.getLLVMEnumerant();
+    os << formatv("  case {0}::{1}:\n", llvmClass, llvmEnumerant);
+    os << formatv("    llvm_unreachable(\"unhandled sentinel {0}::{1}\");\n",
+                  enumAttr.getLLVMClassName(), llvmEnumerant);
+  }
 
   os << "  }\n";
   os << formatv("  llvm_unreachable(\"unknown {0} type\");",
                 enumAttr.getLLVMClassName());
   os << "}\n\n";
 }
 
 // Emits conversion function "Enum convertEnumFromLLVM(LLVMEnum)" and