[Intrinsic] Unify IIT_STRUCT{2-9} into ITT_STRUCT to support upto 257 return values

- Currently, Intrinsic can only have up to 9 return values. In case new
  intrinsics require more than 9 return values, additional ITT_STRUCTxxx
  values need to be added to support > 9 return values.  Instead, this
  patch unifies them into a single IIT_STRUCT followed by a BYTE
  specifying the minimal 2 (encoded as 0) and maximal 257 (encoded as
  255) return values.

Author: darkbuck

llvm/include/llvm/IR/Intrinsics.td

@@ -297,46 +297,39 @@ def IIT_MMX : IIT_VT<x86mmx, 17>;
 def IIT_TOKEN : IIT_VT<token, 18>;
 def IIT_METADATA : IIT_VT<MetadataVT, 19>;
 def IIT_EMPTYSTRUCT : IIT_VT<OtherVT, 20>;
-def IIT_STRUCT2 : IIT_Base<21>;
-def IIT_STRUCT3 : IIT_Base<22>;
-def IIT_STRUCT4 : IIT_Base<23>;
-def IIT_STRUCT5 : IIT_Base<24>;
-def IIT_EXTEND_ARG : IIT_Base<25>;
-def IIT_TRUNC_ARG : IIT_Base<26>;
-def IIT_ANYPTR : IIT_Base<27>;
-def IIT_V1 : IIT_Vec<1, 28>;
-def IIT_VARARG : IIT_VT<isVoid, 29>;
-def IIT_ONE_NTH_ELTS_VEC_ARG : IIT_Base<30>;
-def IIT_SAME_VEC_WIDTH_ARG : IIT_Base<31>;
-def IIT_VEC_OF_ANYPTRS_TO_ELT : IIT_Base<34>;
-def IIT_I128 : IIT_Int<128, 35>;
-def IIT_V512 : IIT_Vec<512, 36>;
-def IIT_V1024 : IIT_Vec<1024, 37>;
-def IIT_STRUCT6 : IIT_Base<38>;
-def IIT_STRUCT7 : IIT_Base<39>;
-def IIT_STRUCT8 : IIT_Base<40>;
-def IIT_F128 : IIT_VT<f128, 41>;
-def IIT_VEC_ELEMENT : IIT_Base<42>;
-def IIT_SCALABLE_VEC : IIT_Base<43>;
-def IIT_SUBDIVIDE2_ARG : IIT_Base<44>;
-def IIT_SUBDIVIDE4_ARG : IIT_Base<45>;
-def IIT_VEC_OF_BITCASTS_TO_INT : IIT_Base<46>;
-def IIT_V128 : IIT_Vec<128, 47>;
-def IIT_BF16 : IIT_VT<bf16, 48>;
-def IIT_STRUCT9 : IIT_Base<49>;
-def IIT_V256 : IIT_Vec<256, 50>;
-def IIT_AMX : IIT_VT<x86amx, 51>;
-def IIT_PPCF128 : IIT_VT<ppcf128, 52>;
-def IIT_V3 : IIT_Vec<3, 53>;
-def IIT_EXTERNREF : IIT_VT<externref, 54>;
-def IIT_FUNCREF : IIT_VT<funcref, 55>;
-def IIT_I2 : IIT_Int<2, 57>;
-def IIT_I4 : IIT_Int<4, 58>;
-def IIT_AARCH64_SVCOUNT : IIT_VT<aarch64svcount, 59>;
-def IIT_V6 : IIT_Vec<6, 60>;
-def IIT_V10 : IIT_Vec<10, 61>;
-def IIT_V2048 : IIT_Vec<2048, 62>;
-def IIT_V4096 : IIT_Vec<4096, 63>;
+def IIT_STRUCT : IIT_Base<21>;
+def IIT_EXTEND_ARG : IIT_Base<22>;
+def IIT_TRUNC_ARG : IIT_Base<23>;
+def IIT_ANYPTR : IIT_Base<24>;
+def IIT_V1 : IIT_Vec<1, 25>;
+def IIT_VARARG : IIT_VT<isVoid, 26>;
+def IIT_ONE_NTH_ELTS_VEC_ARG : IIT_Base<27>;
+def IIT_SAME_VEC_WIDTH_ARG : IIT_Base<28>;
+def IIT_VEC_OF_ANYPTRS_TO_ELT : IIT_Base<29>;
+def IIT_I128 : IIT_Int<128, 30>;
+def IIT_V512 : IIT_Vec<512, 31>;
+def IIT_V1024 : IIT_Vec<1024, 32>;
+def IIT_F128 : IIT_VT<f128, 33>;
+def IIT_VEC_ELEMENT : IIT_Base<34>;
+def IIT_SCALABLE_VEC : IIT_Base<35>;
+def IIT_SUBDIVIDE2_ARG : IIT_Base<36>;
+def IIT_SUBDIVIDE4_ARG : IIT_Base<37>;
+def IIT_VEC_OF_BITCASTS_TO_INT : IIT_Base<38>;
+def IIT_V128 : IIT_Vec<128, 39>;
+def IIT_BF16 : IIT_VT<bf16, 40>;
+def IIT_V256 : IIT_Vec<256, 41>;
+def IIT_AMX : IIT_VT<x86amx, 42>;
+def IIT_PPCF128 : IIT_VT<ppcf128, 43>;
+def IIT_V3 : IIT_Vec<3, 44>;
+def IIT_EXTERNREF : IIT_VT<externref, 45>;
+def IIT_FUNCREF : IIT_VT<funcref, 46>;
+def IIT_I2 : IIT_Int<2, 47>;
+def IIT_I4 : IIT_Int<4, 48>;
+def IIT_AARCH64_SVCOUNT : IIT_VT<aarch64svcount, 49>;
+def IIT_V6 : IIT_Vec<6, 50>;
+def IIT_V10 : IIT_Vec<10, 51>;
+def IIT_V2048 : IIT_Vec<2048, 52>;
+def IIT_V4096 : IIT_Vec<4096, 53>;
 }
 
 defvar IIT_all_FixedTypes = !filter(iit, IIT_all,
@@ -345,19 +338,6 @@ defvar IIT_all_FixedTypes = !filter(iit, IIT_all,
 defvar IIT_all_VectorTypes = !filter(iit, IIT_all,
   !isa<IIT_Vec>(iit));
 
-defvar IIT_RetNumbers = [
-  [IIT_Done.Number],
-  []<int>,
-  [IIT_STRUCT2.Number],
-  [IIT_STRUCT3.Number],
-  [IIT_STRUCT4.Number],
-  [IIT_STRUCT5.Number],
-  [IIT_STRUCT6.Number],
-  [IIT_STRUCT7.Number],
-  [IIT_STRUCT8.Number],
-  [IIT_STRUCT9.Number],
-];
-
 //===----------------------------------------------------------------------===//
 // Types used by intrinsics.
 //===----------------------------------------------------------------------===//
@@ -663,7 +643,10 @@ class TypeInfoGen<
     !if(!isa<LLVMMatchType>(ty), ACTys[MappingRIdxs[ty.Number]], ty));
 
   list<int> TypeSig = !listflatten(!listconcat(
-    [IIT_RetNumbers[!size(RetTypes)]],
+    [!cond(
+      !eq(!size(RetTypes), 0): [IIT_Done.Number],
+      !eq(!size(RetTypes), 1): []<int>,
+      true: [IIT_STRUCT.Number, !sub(!size(RetTypes), 2)])],
     !foreach(i, !range(AllTypes),
       !foreach(a, AllTypes[i].Sig,
         ResolveArgCode<

llvm/lib/IR/Intrinsics.cpp

@@ -207,7 +207,6 @@ DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
   bool IsScalableVector = (LastInfo == IIT_SCALABLE_VEC);
 
   IIT_Info Info = IIT_Info(Infos[NextElt++]);
-  unsigned StructElts = 2;
 
   switch (Info) {
   case IIT_Done:
@@ -390,28 +389,9 @@ DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
   case IIT_EMPTYSTRUCT:
     OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
     return;
-  case IIT_STRUCT9:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT8:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT7:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT6:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT5:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT4:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT3:
-    ++StructElts;
-    [[fallthrough]];
-  case IIT_STRUCT2: {
+  case IIT_STRUCT: {
+    unsigned StructElts = Infos[NextElt++] + 2;
+
     OutputTable.push_back(
         IITDescriptor::get(IITDescriptor::Struct, StructElts));
 

llvm/test/TableGen/intrinsic-struct.td

@@ -1,22 +1,58 @@
 // RUN: llvm-tblgen -gen-intrinsic-enums -I %p/../../include %s -DTEST_INTRINSICS_SUPPRESS_DEFS | FileCheck %s --check-prefix=CHECK-ENUM
-// RUN: llvm-tblgen -gen-intrinsic-impl -I %p/../../include %s -DTEST_INTRINSICS_SUPPRESS_DEFS > /dev/null 2>&1
+// RUN: llvm-tblgen -gen-intrinsic-impl -I %p/../../include %s -DTEST_INTRINSICS_SUPPRESS_DEFS | FileCheck %s --check-prefix=CHECK-IMPL
 // RUN: not llvm-tblgen -gen-intrinsic-impl -I %p/../../include %s -DTEST_INTRINSICS_SUPPRESS_DEFS -DENABLE_ERROR 2>&1 | FileCheck %s --check-prefix=CHECK-ERROR
 
 // XFAIL: vg_leak
 
 include "llvm/IR/Intrinsics.td"
 
-// Make sure we can return up to 9 values.
-// CHECK-ENUM: returns_9_results = {{[0-9]+}}, // llvm.returns.9.results
-def int_returns_9_results : Intrinsic<
-                              !listsplat(llvm_anyint_ty, 9),
-                              [], [], "llvm.returns.9.results">;
+// Make sure we can return up to 257 values. Intrinsics are in alphabetical order.
+// CHECK-ENUM: returns_a0_results = {{[0-9]+}}, // llvm.returns.a0.results
+// CHECK-ENUM: returns_b1_results, // llvm.returns.b1.results
+// CHECK-ENUM: returns_c2_results, // llvm.returns.c2.results
+// CHECK-ENUM: returns_d9_results, // llvm.returns.d9.results
+// CHECK-ENUM: returns_e10_results, // llvm.returns.e10.results
+// CHECK-ENUM: returns_f257_results, // llvm.returns.f257.results
 
-#ifdef ENABLE_ERROR
-// CHECK-ERROR: error: intrinsics can only return upto 9 values, 'int_returns_10_results' returns 10 values
-// CHECK-ERROR-NEXT: def int_returns_10_results : Intrinsic<
-def int_returns_10_results : Intrinsic<
+// Make sure the encoding table is correctly generated.
+// CHECK-IMPL: IIT_LongEncodingTable
+// CHECK-IMPL-NEXT: 21, 255
+// CHECK-IMPL-SAME: 15, 1, 15, 9, 15, 17, 15, 25, 15, 33, 15, 41, 15, 49, 15, 57, 15, 65, 15, 73, 15, 81,
+// CHECK-IMPL-NEXT: 21, 0
+// CHECK-IMPL-SAME: 15, 1, 15, 9, 0
+// CHECK-IMPL-NEXT: 21, 7
+// CHECK-IMPL-SAME: 15, 1, 15, 9, 15, 17, 15, 25, 15, 33, 15, 41, 15, 49, 15, 57, 15, 65, 0
+// CHECK-IMPL-NEXT: 21, 8
+// CHECK-IMPL-SAME: 15, 1, 15, 9, 15, 17, 15, 25, 15, 33, 15, 41, 15, 49, 15, 57, 15, 65, 15, 73, 0
+def int_returns_a0_results : Intrinsic<
+                             [],
+                             [], [], "llvm.returns.a0.results">;
+
+def int_returns_b1_results : Intrinsic<
+                             [llvm_anyint_ty],
+                             [], [], "llvm.returns.b1.results">;
+
+def int_returns_c2_results : Intrinsic<
+                             !listsplat(llvm_anyint_ty, 2),
+                             [], [], "llvm.returns.c2.results">;
+
+def int_returns_d9_results : Intrinsic<
+                             !listsplat(llvm_anyint_ty, 9),
+                             [], [], "llvm.returns.d9.results">;
+
+def int_returns_e10_results : Intrinsic<
                               !listsplat(llvm_anyint_ty, 10),
-                              [], [], "llvm.returns.10.results">;
+                              [], [], "llvm.returns.e10.results">;
+
+def int_returns_f257_results : Intrinsic<
+                               !listsplat(llvm_anyint_ty, 257),
+                               [], [], "llvm.returns.f257.results">;
+
+#ifdef ENABLE_ERROR
+// CHECK-ERROR: error: intrinsics can only return upto 257 values, 'int_returns_g258_results' returns 258 values
+// CHECK-ERROR-NEXT: def int_returns_g258_results : Intrinsic<
+def int_returns_g258_results : Intrinsic<
+                               !listsplat(llvm_anyint_ty, 258),
+                               [], [], "llvm.returns.g258.results">;
 
 #endif

llvm/test/TableGen/intrinsic-varargs.td

@@ -3,5 +3,5 @@
 
 include "llvm/IR/Intrinsics.td"
 
-// CHECK: /* 0 */ 0, 29, 0,
+// CHECK: /* 0 */ 0, 26, 0,
 def int_foo : Intrinsic<[], [llvm_vararg_ty]>;

llvm/utils/TableGen/Basic/CodeGenIntrinsics.cpp

@@ -21,6 +21,13 @@
 #include <cassert>
 using namespace llvm;
 
+// As the type of more than one return values is represented as an anonymous
+// struct, which is encoded with `IIT_STRUCT` followed by a byte specifying
+// the number of return values, starting from 2 (encoded as 0) to 257
+// (encoded as 255). So, the maximum number of values that an intrinsic can
+// return is 257.
+static constexpr unsigned MaxNumReturn = 257;
+
 //===----------------------------------------------------------------------===//
 // CodeGenIntrinsic Implementation
 //===----------------------------------------------------------------------===//
@@ -29,15 +36,6 @@ CodeGenIntrinsicContext::CodeGenIntrinsicContext(const RecordKeeper &RC) {
   for (const Record *Rec : RC.getAllDerivedDefinitions("IntrinsicProperty"))
     if (Rec->getValueAsBit("IsDefault"))
       DefaultProperties.push_back(Rec);
-
-  // The maximum number of values that an intrinsic can return is the size of
-  // of `IIT_RetNumbers` list - 1 (since we index into this list using the
-  // number of return values as the index).
-  const auto *IIT_RetNumbers =
-      dyn_cast_or_null<ListInit>(RC.getGlobal("IIT_RetNumbers"));
-  if (!IIT_RetNumbers)
-    PrintFatalError("unable to find 'IIT_RetNumbers' list");
-  MaxNumReturn = IIT_RetNumbers->size() - 1;
 }
 
 CodeGenIntrinsicTable::CodeGenIntrinsicTable(const RecordKeeper &RC) {
@@ -302,11 +300,10 @@ CodeGenIntrinsic::CodeGenIntrinsic(const Record *R,
   }
 
   unsigned NumRet = R->getValueAsListInit("RetTypes")->size();
-  if (NumRet > Ctx.MaxNumReturn)
+  if (NumRet > MaxNumReturn)
     PrintFatalError(DefLoc, "intrinsics can only return upto " +
-                                Twine(Ctx.MaxNumReturn) + " values, '" +
-                                DefName + "' returns " + Twine(NumRet) +
-                                " values");
+                                Twine(MaxNumReturn) + " values, '" + DefName +
+                                "' returns " + Twine(NumRet) + " values");
 
   const Record *TypeInfo = R->getValueAsDef("TypeInfo");
   if (!TypeInfo->isSubClassOf("TypeInfoGen"))

llvm/utils/TableGen/Basic/CodeGenIntrinsics.h

@@ -30,9 +30,6 @@ class RecordKeeper;
 struct CodeGenIntrinsicContext {
   explicit CodeGenIntrinsicContext(const RecordKeeper &RC);
   std::vector<const Record *> DefaultProperties;
-
-  // Maximum number of values an intrinsic can return.
-  unsigned MaxNumReturn;
 };
 
 struct CodeGenIntrinsic {