Fixed version of optimized integer divide is now fixed. Calculate the
quotient, not the remainder. Also, make sure to remove the old div operand
from the ExprMap and let SelectExpr insert the new one.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21111 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 465a9bc..3ece1b2 100644
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -551,7 +551,7 @@
if (v <= -2 || v >= 2) { return 4; }
break;
case ISD::UDIV:
- if (v != 0) { return 4; }
+ if (v > 1) { return 4; }
break;
}
return 0;
@@ -711,10 +711,7 @@
// Extract the sign bit and add it to the quotient
SDOperand T =
ISelDAG->getNode(ISD::SRL, MVT::i32, Q, ISelDAG->getConstant(31, MVT::i32));
- Q = ISelDAG->getNode(ISD::ADD, MVT::i32, Q, T);
- // Compute the remainder
- T = ISelDAG->getNode(ISD::MUL, MVT::i32, Q, N.getOperand(1));
- return ISelDAG->getNode(ISD::SUB, MVT::i32, N.getOperand(0), T);
+ return ISelDAG->getNode(ISD::ADD, MVT::i32, Q, T);
}
/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
@@ -739,9 +736,7 @@
Q = ISelDAG->getNode(ISD::SRL, MVT::i32, NPQ,
ISelDAG->getConstant(magics.s-1, MVT::i32));
}
- // Compute the remainder
- SDOperand T = ISelDAG->getNode(ISD::MUL, MVT::i32, Q, N.getOperand(1));
- return ISelDAG->getNode(ISD::SUB, MVT::i32, N.getOperand(0), T);
+ return Q;
}
/// getGlobalBaseReg - Output the instructions required to put the
@@ -1601,11 +1596,12 @@
return Result;
// If this is a divide by constant, we can emit code using some magic
// constants to implement it as a multiply instead.
- //case 4:
- // if (opcode == ISD::SDIV)
- // return SelectExpr(BuildSDIVSequence(N));
- // else
- // return SelectExpr(BuildUDIVSequence(N));
+ case 4:
+ ExprMap.erase(N);
+ if (opcode == ISD::SDIV)
+ return SelectExpr(BuildSDIVSequence(N));
+ else
+ return SelectExpr(BuildUDIVSequence(N));
}
Tmp1 = SelectExpr(N.getOperand(0));
Tmp2 = SelectExpr(N.getOperand(1));