Rename the VECREDUCE_STRICT_{FADD,FMUL} SDNodes to VECREDUCE_SEQ_{FADD,FMUL}.

The STRICT was causing unnecessary confusion. I think SEQ is a more accurate
name for what they actually do, and the other obvious option of "ORDERED"
has the issue of already having a meaning in FP contexts.

Differential Revision: https://reviews.llvm.org/D88791

diff --git a/llvm/include/llvm/CodeGen/ISDOpcodes.h b/llvm/include/llvm/CodeGen/ISDOpcodes.h
index 19d7307..dbe1f08 100644 (file)
--- a/llvm/include/llvm/CodeGen/ISDOpcodes.h
+++ b/llvm/include/llvm/CodeGen/ISDOpcodes.h
@@ -1103,12 +1103,25 @@ enum NodeType {
 
   /// Generic reduction nodes. These nodes represent horizontal vector
   /// reduction operations, producing a scalar result.
-  /// The STRICT variants perform reductions in sequential order. The first
+  /// The SEQ variants perform reductions in sequential order. The first
   /// operand is an initial scalar accumulator value, and the second operand
   /// is the vector to reduce.
-  VECREDUCE_STRICT_FADD,
-  VECREDUCE_STRICT_FMUL,
-  /// These reductions are non-strict, and have a single vector operand.
+  /// E.g. RES = VECREDUCE_SEQ_FADD f32 ACC, <4 x f32> SRC_VEC
+  ///  ... is equivalent to
+  /// RES = (((ACC + SRC_VEC[0]) + SRC_VEC[1]) + SRC_VEC[2]) + SRC_VEC[3]
+  VECREDUCE_SEQ_FADD,
+  VECREDUCE_SEQ_FMUL,
+
+  /// These reductions have relaxed evaluation order semantics, and have a
+  /// single vector operand. The order of evaluation is unspecified. For
+  /// pow-of-2 vectors, one valid legalizer expansion is to use a tree
+  /// reduction, i.e.:
+  /// For RES = VECREDUCE_FADD <8 x f16> SRC_VEC
+  ///   PART_RDX = FADD SRC_VEC[0:3], SRC_VEC[4:7]
+  ///   PART_RDX2 = FADD PART_RDX[0:1], PART_RDX[2:3]
+  ///   RES = FADD PART_RDX2[0], PART_RDX2[1]
+  /// For non-pow-2 vectors, this can be computed by extracting each element
+  /// and performing the operation as if it were scalarized.
   VECREDUCE_FADD,
   VECREDUCE_FMUL,
   /// FMIN/FMAX nodes can have flags, for NaN/NoNaN variants.

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 2f36011..01972b0 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -8943,7 +8943,7 @@ void SelectionDAGBuilder::visitVectorReduce(const CallInst &I,
                         DAG.getNode(ISD::VECREDUCE_FADD, dl, VT, Op2, SDFlags),
                         SDFlags);
     else
-      Res = DAG.getNode(ISD::VECREDUCE_STRICT_FADD, dl, VT, Op1, Op2, SDFlags);
+      Res = DAG.getNode(ISD::VECREDUCE_SEQ_FADD, dl, VT, Op1, Op2, SDFlags);
     break;
   case Intrinsic::vector_reduce_fmul:
     if (SDFlags.hasAllowReassociation())
@@ -8951,7 +8951,7 @@ void SelectionDAGBuilder::visitVectorReduce(const CallInst &I,
                         DAG.getNode(ISD::VECREDUCE_FMUL, dl, VT, Op2, SDFlags),
                         SDFlags);
     else
-      Res = DAG.getNode(ISD::VECREDUCE_STRICT_FMUL, dl, VT, Op1, Op2, SDFlags);
+      Res = DAG.getNode(ISD::VECREDUCE_SEQ_FMUL, dl, VT, Op1, Op2, SDFlags);
     break;
   case Intrinsic::vector_reduce_add:
     Res = DAG.getNode(ISD::VECREDUCE_ADD, dl, VT, Op1);

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index f854a4f..1587398 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -450,9 +450,9 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
     case ISD::SETFALSE2:                return "setfalse2";
     }
   case ISD::VECREDUCE_FADD:             return "vecreduce_fadd";
-  case ISD::VECREDUCE_STRICT_FADD:      return "vecreduce_strict_fadd";
+  case ISD::VECREDUCE_SEQ_FADD:         return "vecreduce_seq_fadd";
   case ISD::VECREDUCE_FMUL:             return "vecreduce_fmul";
-  case ISD::VECREDUCE_STRICT_FMUL:      return "vecreduce_strict_fmul";
+  case ISD::VECREDUCE_SEQ_FMUL:         return "vecreduce_seq_fmul";
   case ISD::VECREDUCE_ADD:              return "vecreduce_add";
   case ISD::VECREDUCE_MUL:              return "vecreduce_mul";
   case ISD::VECREDUCE_AND:              return "vecreduce_and";