[Intrinsic] Add fixed point division intrinsics.

Summary:
This patch adds intrinsics and ISelDAG nodes for
signed and unsigned fixed-point division:

  llvm.sdiv.fix.*
  llvm.udiv.fix.*

These intrinsics perform scaled division on two
integers or vectors of integers. They are required
for the implementation of the Embedded-C fixed-point
arithmetic in Clang.

Patch by: ebevhan

Reviewers: bjope, leonardchan, efriedma, craig.topper

Reviewed By: craig.topper

Subscribers: Ka-Ka, ilya, hiraditya, jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70007

1 files changed, 15 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index 0975d2ad49d..13813008eff 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -146,6 +146,7 @@ class VectorLegalizer {
   SDValue ExpandMULO(SDValue Op);
   SDValue ExpandAddSubSat(SDValue Op);
   SDValue ExpandFixedPointMul(SDValue Op);
+  SDValue ExpandFixedPointDiv(SDValue Op);
   SDValue ExpandStrictFPOp(SDValue Op);
 
   SDValue UnrollStrictFPOp(SDValue Op);
@@ -442,7 +443,9 @@ SDValue VectorLegalizer::LegalizeOp(SDValue Op) {
   case ISD::SMULFIX:
   case ISD::SMULFIXSAT:
   case ISD::UMULFIX:
-  case ISD::UMULFIXSAT: {
+  case ISD::UMULFIXSAT:
+  case ISD::SDIVFIX:
+  case ISD::UDIVFIX: {
     unsigned Scale = Node->getConstantOperandVal(2);
     Action = TLI.getFixedPointOperationAction(Node->getOpcode(),
                                               Node->getValueType(0), Scale);
@@ -849,6 +852,9 @@ SDValue VectorLegalizer::Expand(SDValue Op) {
     // targets? This should probably be investigated. And if we still prefer to
     // unroll an explanation could be helpful.
     return DAG.UnrollVectorOp(Op.getNode());
+  case ISD::SDIVFIX:
+  case ISD::UDIVFIX:
+    return ExpandFixedPointDiv(Op);
 #define INSTRUCTION(NAME, NARG, ROUND_MODE, INTRINSIC, DAGN)                   \
   case ISD::STRICT_##DAGN:
 #include "llvm/IR/ConstrainedOps.def"
@@ -1392,6 +1398,14 @@ SDValue VectorLegalizer::ExpandFixedPointMul(SDValue Op) {
   return DAG.UnrollVectorOp(Op.getNode());
 }
 
+SDValue VectorLegalizer::ExpandFixedPointDiv(SDValue Op) {
+  SDNode *N = Op.getNode();
+  if (SDValue Expanded = TLI.expandFixedPointDiv(N->getOpcode(), SDLoc(N),
+          N->getOperand(0), N->getOperand(1), N->getConstantOperandVal(2), DAG))
+    return Expanded;
+  return DAG.UnrollVectorOp(N);
+}
+
 SDValue VectorLegalizer::ExpandStrictFPOp(SDValue Op) {
   if (Op.getOpcode() == ISD::STRICT_UINT_TO_FP)
     return ExpandUINT_TO_FLOAT(Op);