DAGCombiner: Turn divs of vector splats into vectorized multiplications.
Otherwise the legalizer would just scalarize everything. Support for
mulhi in the targets isn't that great yet so on most targets we get
exactly the same scalarized output. Add a test for x86 vector udiv.
I had to disable the mulhi nodes on ARM because there aren't any patterns
for it. As far as I know ARM has instructions for getting the high part of
a multiply so this should be fixed.
llvm-svn: 207315
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index b5e4358..dc92795 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2602,9 +2602,9 @@
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
-SDValue TargetLowering::
-BuildSDIV(SDNode *N, SelectionDAG &DAG, bool IsAfterLegalization,
- std::vector<SDNode*> *Created) const {
+SDValue TargetLowering::BuildSDIV(SDNode *N, const APInt &Divisor,
+ SelectionDAG &DAG, bool IsAfterLegalization,
+ std::vector<SDNode *> *Created) const {
EVT VT = N->getValueType(0);
SDLoc dl(N);
@@ -2613,8 +2613,7 @@
if (!isTypeLegal(VT))
return SDValue();
- APInt d = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
- APInt::ms magics = d.magic();
+ APInt::ms magics = Divisor.magic();
// Multiply the numerator (operand 0) by the magic value
// FIXME: We should support doing a MUL in a wider type
@@ -2631,13 +2630,13 @@
else
return SDValue(); // No mulhs or equvialent
// If d > 0 and m < 0, add the numerator
- if (d.isStrictlyPositive() && magics.m.isNegative()) {
+ if (Divisor.isStrictlyPositive() && magics.m.isNegative()) {
Q = DAG.getNode(ISD::ADD, dl, VT, Q, N->getOperand(0));
if (Created)
Created->push_back(Q.getNode());
}
// If d < 0 and m > 0, subtract the numerator.
- if (d.isNegative() && magics.m.isStrictlyPositive()) {
+ if (Divisor.isNegative() && magics.m.isStrictlyPositive()) {
Q = DAG.getNode(ISD::SUB, dl, VT, Q, N->getOperand(0));
if (Created)
Created->push_back(Q.getNode());
@@ -2650,9 +2649,9 @@
Created->push_back(Q.getNode());
}
// Extract the sign bit and add it to the quotient
- SDValue T =
- DAG.getNode(ISD::SRL, dl, VT, Q, DAG.getConstant(VT.getSizeInBits()-1,
- getShiftAmountTy(Q.getValueType())));
+ SDValue T = DAG.getNode(ISD::SRL, dl, VT, Q,
+ DAG.getConstant(VT.getScalarSizeInBits() - 1,
+ getShiftAmountTy(Q.getValueType())));
if (Created)
Created->push_back(T.getNode());
return DAG.getNode(ISD::ADD, dl, VT, Q, T);
@@ -2662,9 +2661,9 @@
/// return a DAG expression to select that will generate the same value by
/// multiplying by a magic number. See:
/// <http://the.wall.riscom.net/books/proc/ppc/cwg/code2.html>
-SDValue TargetLowering::
-BuildUDIV(SDNode *N, SelectionDAG &DAG, bool IsAfterLegalization,
- std::vector<SDNode*> *Created) const {
+SDValue TargetLowering::BuildUDIV(SDNode *N, const APInt &Divisor,
+ SelectionDAG &DAG, bool IsAfterLegalization,
+ std::vector<SDNode *> *Created) const {
EVT VT = N->getValueType(0);
SDLoc dl(N);
@@ -2675,22 +2674,21 @@
// FIXME: We should use a narrower constant when the upper
// bits are known to be zero.
- const APInt &N1C = cast<ConstantSDNode>(N->getOperand(1))->getAPIntValue();
- APInt::mu magics = N1C.magicu();
+ APInt::mu magics = Divisor.magicu();
SDValue Q = N->getOperand(0);
// If the divisor is even, we can avoid using the expensive fixup by shifting
// the divided value upfront.
- if (magics.a != 0 && !N1C[0]) {
- unsigned Shift = N1C.countTrailingZeros();
+ if (magics.a != 0 && !Divisor[0]) {
+ unsigned Shift = Divisor.countTrailingZeros();
Q = DAG.getNode(ISD::SRL, dl, VT, Q,
DAG.getConstant(Shift, getShiftAmountTy(Q.getValueType())));
if (Created)
Created->push_back(Q.getNode());
// Get magic number for the shifted divisor.
- magics = N1C.lshr(Shift).magicu(Shift);
+ magics = Divisor.lshr(Shift).magicu(Shift);
assert(magics.a == 0 && "Should use cheap fixup now");
}
@@ -2709,7 +2707,7 @@
Created->push_back(Q.getNode());
if (magics.a == 0) {
- assert(magics.s < N1C.getBitWidth() &&
+ assert(magics.s < Divisor.getBitWidth() &&
"We shouldn't generate an undefined shift!");
return DAG.getNode(ISD::SRL, dl, VT, Q,
DAG.getConstant(magics.s, getShiftAmountTy(Q.getValueType())));