[PATCH] D139757: [RISCV] Use reduction result type for EXTRACT_VECTOR_ELT in lowerReductionSeq.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: reames, frasercrmck, rogfer01.
Herald added subscribers: sunshaoce, VincentWu, StephenFan, vkmr, evandro, luismarques, apazos, sameer.abuasal, s.egerton, Jim, benna, psnobl, jocewei, PkmX, the_o, brucehoult, MartinMosbeck, edward-jones, zzheng, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, simoncook, johnrusso, rbar, asb, hiraditya, arichardson.
Herald added a project: All.
craig.topper requested review of this revision.
Herald added subscribers: pcwang-thead, eopXD, MaskRay.
Herald added a project: LLVM.

Remove the call to getSExtOrTrunc.

Reduction ISD nodes produce a scalar result and that result is
allowed to be larger than the vector element type due to type
legalization. This is the same rule we allow for EXTRACT_VECTOR_ELT
for the same reason.

We can copy the result type over from the reduction node to
EXTRACT_VECTOR_ELT.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D139757

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp


Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -5805,12 +5805,11 @@
 
 /// Helper to lower a reduction sequence of the form:
 /// scalar = reduce_op vec, scalar_start
-static SDValue lowerReductionSeq(unsigned RVVOpcode, SDValue StartValue,
-                                 SDValue Vec, SDValue Mask, SDValue VL,
-                                 SDLoc DL, SelectionDAG &DAG,
+static SDValue lowerReductionSeq(unsigned RVVOpcode, MVT ResVT,
+                                 SDValue StartValue, SDValue Vec, SDValue Mask,
+                                 SDValue VL, SDLoc DL, SelectionDAG &DAG,
                                  const RISCVSubtarget &Subtarget) {
   const MVT VecVT = Vec.getSimpleValueType();
-  const MVT VecEltVT = VecVT.getVectorElementType();
   const MVT M1VT = getLMUL1VT(VecVT);
   const MVT XLenVT = Subtarget.getXLenVT();
 
@@ -5820,7 +5819,7 @@
   SDValue PassThru = hasNonZeroAVL(VL) ? DAG.getUNDEF(M1VT) : InitialSplat;
   SDValue Reduction = DAG.getNode(RVVOpcode, DL, M1VT, PassThru, Vec,
                                   InitialSplat, Mask, VL);
-  return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, VecEltVT, Reduction,
+  return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, ResVT, Reduction,
                      DAG.getConstant(0, DL, XLenVT));
 }
 
@@ -5860,9 +5859,8 @@
 
   SDValue NeutralElem =
       DAG.getNeutralElement(BaseOpc, DL, VecEltVT, SDNodeFlags());
-  SDValue Elt0 = lowerReductionSeq(RVVOpcode, NeutralElem, Vec, Mask, VL,
-                                   DL, DAG, Subtarget);
-  return DAG.getSExtOrTrunc(Elt0, DL, Op.getValueType());
+  return lowerReductionSeq(RVVOpcode, Op.getSimpleValueType(), NeutralElem, Vec,
+                           Mask, VL, DL, DAG, Subtarget);
 }
 
 // Given a reduction op, this function returns the matching reduction opcode,
@@ -5913,8 +5911,8 @@
   }
 
   auto [Mask, VL] = getDefaultVLOps(VecVT, ContainerVT, DL, DAG, Subtarget);
-  return lowerReductionSeq(RVVOpcode, ScalarVal, VectorVal, Mask, VL, DL, DAG,
-                           Subtarget);
+  return lowerReductionSeq(RVVOpcode, Op.getSimpleValueType(), ScalarVal,
+                           VectorVal, Mask, VL, DL, DAG, Subtarget);
 }
 
 static unsigned getRVVVPReductionOp(unsigned ISDOpcode) {
@@ -5969,11 +5967,8 @@
 
   SDValue VL = Op.getOperand(3);
   SDValue Mask = Op.getOperand(2);
-  SDValue Elt0 = lowerReductionSeq(RVVOpcode, Op.getOperand(0), Vec, Mask, VL,
-                                   DL, DAG, Subtarget);
-  if (!VecVT.isInteger())
-    return Elt0;
-  return DAG.getSExtOrTrunc(Elt0, DL, Op.getValueType());
+  return lowerReductionSeq(RVVOpcode, Op.getSimpleValueType(), Op.getOperand(0),
+                           Vec, Mask, VL, DL, DAG, Subtarget);
 }
 
 SDValue RISCVTargetLowering::lowerINSERT_SUBVECTOR(SDValue Op,


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D139757.481796.patch
Type: text/x-patch
Size: 2976 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20221210/21a3ee92/attachment.bin>