[LegalizeDAG] Add generic vector CTPOP expansion (PR32655)

This patch adds support for expanding vector CTPOP instructions and removes the x86 'bitmath' lowering which replicates the same expansion.

Differential Revision: https://reviews.llvm.org/D53258

llvm-svn: 345869

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index 1b68f217590..284c4e5b3dd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -129,6 +129,7 @@ class VectorLegalizer {
   SDValue ExpandFNEG(SDValue Op);
   SDValue ExpandFSUB(SDValue Op);
   SDValue ExpandBITREVERSE(SDValue Op);
+  SDValue ExpandCTPOP(SDValue Op);
   SDValue ExpandCTLZ(SDValue Op);
   SDValue ExpandCTTZ(SDValue Op);
   SDValue ExpandFMINNUM_FMAXNUM(SDValue Op);
@@ -726,6 +727,8 @@ SDValue VectorLegalizer::Expand(SDValue Op) {
     return UnrollVSETCC(Op);
   case ISD::BITREVERSE:
     return ExpandBITREVERSE(Op);
+  case ISD::CTPOP:
+    return ExpandCTPOP(Op);
   case ISD::CTLZ:
   case ISD::CTLZ_ZERO_UNDEF:
     return ExpandCTLZ(Op);
@@ -1104,6 +1107,16 @@ SDValue VectorLegalizer::ExpandFSUB(SDValue Op) {
   return DAG.UnrollVectorOp(Op.getNode());
 }
 
+SDValue VectorLegalizer::ExpandCTPOP(SDValue Op) {
+  // Attempt to expand using TargetLowering.
+  SDValue Result;
+  if (TLI.expandCTPOP(Op.getNode(), Result, DAG))
+    return Result;
+
+  // Otherwise go ahead and unroll.
+  return DAG.UnrollVectorOp(Op.getNode());
+}
+
 SDValue VectorLegalizer::ExpandCTLZ(SDValue Op) {
   // Attempt to expand using TargetLowering.
   SDValue Result;