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Fixed version of optimized integer divide is now fixed. Calculate the

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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
This commit is contained in:
Nate Begeman
2005-04-06 06:44:57 +00:00
parent b70c2f3ef7
commit 27b4c23b80
1 changed files with 9 additions and 13 deletions
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22
lib/Target/PowerPC/PPCISelPattern.cpp
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@@ -551,7 +551,7 @@ static unsigned getImmediateForOpcode(SDOperand N, unsigned Opcode,
if (v <= -2 || v >= 2) { return 4; } if (v <= -2 || v >= 2) { return 4; }
break; break;
case ISD::UDIV: case ISD::UDIV:
if (v != 0) { return 4; } if (v > 1) { return 4; }
break; break;
} }
return 0; return 0;
@@ -711,10 +711,7 @@ SDOperand ISel::BuildSDIVSequence(SDOperand N) {
// Extract the sign bit and add it to the quotient // Extract the sign bit and add it to the quotient
SDOperand T = SDOperand T =
ISelDAG->getNode(ISD::SRL, MVT::i32, Q, ISelDAG->getConstant(31, MVT::i32)); ISelDAG->getNode(ISD::SRL, MVT::i32, Q, ISelDAG->getConstant(31, MVT::i32));
Q = ISelDAG->getNode(ISD::ADD, MVT::i32, Q, T); return 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);
} }
/// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant, /// BuildUDIVSequence - Given an ISD::UDIV node expressing a divide by constant,
@@ -739,9 +736,7 @@ SDOperand ISel::BuildUDIVSequence(SDOperand N) {
Q = ISelDAG->getNode(ISD::SRL, MVT::i32, NPQ, Q = ISelDAG->getNode(ISD::SRL, MVT::i32, NPQ,
ISelDAG->getConstant(magics.s-1, MVT::i32)); ISelDAG->getConstant(magics.s-1, MVT::i32));
} }
// Compute the remainder return Q;
SDOperand T = ISelDAG->getNode(ISD::MUL, MVT::i32, Q, N.getOperand(1));
return ISelDAG->getNode(ISD::SUB, MVT::i32, N.getOperand(0), T);
} }
/// getGlobalBaseReg - Output the instructions required to put the /// getGlobalBaseReg - Output the instructions required to put the
@@ -1601,11 +1596,12 @@ unsigned ISel::SelectExpr(SDOperand N) {
return Result; return Result;
// If this is a divide by constant, we can emit code using some magic // If this is a divide by constant, we can emit code using some magic
// constants to implement it as a multiply instead. // constants to implement it as a multiply instead.
//case 4: case 4:
// if (opcode == ISD::SDIV) ExprMap.erase(N);
// return SelectExpr(BuildSDIVSequence(N)); if (opcode == ISD::SDIV)
// else return SelectExpr(BuildSDIVSequence(N));
// return SelectExpr(BuildUDIVSequence(N)); else
return SelectExpr(BuildUDIVSequence(N));
} }
Tmp1 = SelectExpr(N.getOperand(0)); Tmp1 = SelectExpr(N.getOperand(0));
Tmp2 = SelectExpr(N.getOperand(1)); Tmp2 = SelectExpr(N.getOperand(1));