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

1 files changed, 9 insertions, 13 deletions

diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 465a9bccf1..3ece1b29f9 100644
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -551,7 +551,7 @@ static unsigned getImmediateForOpcode(SDOperand N, unsigned Opcode,
     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 @@ SDOperand ISel::BuildSDIVSequence(SDOperand N) {
   // 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 @@ SDOperand ISel::BuildUDIVSequence(SDOperand N) {
     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 @@ unsigned ISel::SelectExpr(SDOperand N) {
       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));