From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Sat, 26 Apr 2014 12:06:11 +0000 (+0000)
Subject: X86: Custom lower v4i32 UMUL_LOHI into 2 pmuludqs.
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=05e00b6e65f0aa258dd2fe45778fc084cbb93c67;p=oota-llvm.git

X86: Custom lower v4i32 UMUL_LOHI into 2 pmuludqs.

Test will follow soon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207314 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 7d195fcdae9..6ce1fa75f66 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -826,7 +826,9 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::FRINT, VT, Expand);
     setOperationAction(ISD::FNEARBYINT, VT, Expand);
     setOperationAction(ISD::SMUL_LOHI, VT, Expand);
+    setOperationAction(ISD::MULHS, VT, Expand);
     setOperationAction(ISD::UMUL_LOHI, VT, Expand);
+    setOperationAction(ISD::MULHU, VT, Expand);
     setOperationAction(ISD::SDIVREM, VT, Expand);
     setOperationAction(ISD::UDIVREM, VT, Expand);
     setOperationAction(ISD::FPOW, VT, Expand);
@@ -938,6 +940,7 @@ void X86TargetLowering::resetOperationActions() {
     setOperationAction(ISD::ADD,                MVT::v2i64, Legal);
     setOperationAction(ISD::MUL,                MVT::v4i32, Custom);
     setOperationAction(ISD::MUL,                MVT::v2i64, Custom);
+    setOperationAction(ISD::UMUL_LOHI,          MVT::v4i32, Custom);
     setOperationAction(ISD::SUB,                MVT::v16i8, Legal);
     setOperationAction(ISD::SUB,                MVT::v8i16, Legal);
     setOperationAction(ISD::SUB,                MVT::v4i32, Legal);
@@ -1226,6 +1229,8 @@ void X86TargetLowering::resetOperationActions() {
       setOperationAction(ISD::MUL,             MVT::v16i16, Legal);
       // Don't lower v32i8 because there is no 128-bit byte mul
 
+      setOperationAction(ISD::UMUL_LOHI,       MVT::v8i32, Custom);
+
       setOperationAction(ISD::VSELECT,         MVT::v32i8, Legal);
 
       setOperationAction(ISD::SDIV,            MVT::v8i32, Custom);
@@ -13157,6 +13162,37 @@ static SDValue LowerMUL(SDValue Op, const X86Subtarget *Subtarget,
   return DAG.getNode(ISD::ADD, dl, VT, Res, AhiBlo);
 }
 
+static SDValue LowerUMUL_LOHI(SDValue Op, const X86Subtarget *Subtarget,
+                              SelectionDAG &DAG) {
+  SDValue Op0 = Op.getOperand(0), Op1 = Op.getOperand(1);
+  EVT VT = Op0.getValueType();
+  SDLoc dl(Op);
+
+  assert((VT == MVT::v4i32 && Subtarget->hasSSE2()) ||
+         (VT == MVT::v8i32 && Subtarget->hasInt256()));
+
+  // Get the high parts.
+  const int Mask[] = {1, 2, 3, 4, 5, 6, 7, 8};
+  SDValue Hi0 = DAG.getVectorShuffle(VT, dl, Op0, Op0, Mask);
+  SDValue Hi1 = DAG.getVectorShuffle(VT, dl, Op1, Op1, Mask);
+
+  // Emit two multiplies, one for the lower 2 ints and one for the higher 2
+  // ints.
+  MVT MulVT = VT == MVT::v4i32 ? MVT::v2i64 : MVT::v4i64;
+  SDValue Mul1 = DAG.getNode(ISD::BITCAST, dl, VT,
+                             DAG.getNode(X86ISD::PMULUDQ, dl, MulVT, Op0, Op1));
+  SDValue Mul2 = DAG.getNode(ISD::BITCAST, dl, VT,
+                             DAG.getNode(X86ISD::PMULUDQ, dl, MulVT, Hi0, Hi1));
+
+  // Shuffle it back into the right order.
+  const int HighMask[] = {1, 3, 5, 7, 9, 11, 13, 15};
+  SDValue Highs = DAG.getVectorShuffle(VT, dl, Mul1, Mul2, HighMask);
+  const int LowMask[] = {0, 2, 4, 6, 8, 10, 12, 14};
+  SDValue Lows = DAG.getVectorShuffle(VT, dl, Mul1, Mul2, LowMask);
+
+  return DAG.getNode(ISD::MERGE_VALUES, dl, Op.getValueType(), Highs, Lows);
+}
+
 static SDValue LowerSDIV(SDValue Op, SelectionDAG &DAG) {
   MVT VT = Op.getSimpleValueType();
   MVT EltTy = VT.getVectorElementType();
@@ -14201,6 +14237,7 @@ SDValue X86TargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::CTLZ_ZERO_UNDEF:    return LowerCTLZ_ZERO_UNDEF(Op, DAG);
   case ISD::CTTZ:               return LowerCTTZ(Op, DAG);
   case ISD::MUL:                return LowerMUL(Op, Subtarget, DAG);
+  case ISD::UMUL_LOHI:          return LowerUMUL_LOHI(Op, Subtarget, DAG);
   case ISD::SRA:
   case ISD::SRL:
   case ISD::SHL:                return LowerShift(Op, Subtarget, DAG);