[APInt] Use lshrInPlace to replace lshr where possible

This patch uses lshrInPlace to replace code where the object that lshr is called on is being overwritten with the result.

This adds an lshrInPlace(const APInt &) version as well.

Differential Revision: https://reviews.llvm.org/D32155

llvm-svn: 300566

1 files changed, 5 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 003ea5030bf..8c677d901e4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2330,8 +2330,8 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero,
     if (const APInt *ShAmt = getValidShiftAmountConstant(Op)) {
       computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, DemandedElts,
                        Depth + 1);
-      KnownZero = KnownZero.lshr(*ShAmt);
-      KnownOne  = KnownOne.lshr(*ShAmt);
+      KnownZero.lshrInPlace(*ShAmt);
+      KnownOne.lshrInPlace(*ShAmt);
       // High bits are known zero.
       KnownZero.setHighBits(ShAmt->getZExtValue());
     }
@@ -2340,12 +2340,12 @@ void SelectionDAG::computeKnownBits(SDValue Op, APInt &KnownZero,
     if (const APInt *ShAmt = getValidShiftAmountConstant(Op)) {
       computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, DemandedElts,
                        Depth + 1);
-      KnownZero = KnownZero.lshr(*ShAmt);
-      KnownOne  = KnownOne.lshr(*ShAmt);
+      KnownZero.lshrInPlace(*ShAmt);
+      KnownOne.lshrInPlace(*ShAmt);
       // If we know the value of the sign bit, then we know it is copied across
       // the high bits by the shift amount.
       APInt SignBit = APInt::getSignBit(BitWidth);
-      SignBit = SignBit.lshr(*ShAmt);  // Adjust to where it is now in the mask.
+      SignBit.lshrInPlace(*ShAmt);  // Adjust to where it is now in the mask.
       if (KnownZero.intersects(SignBit)) {
         KnownZero.setHighBits(ShAmt->getZExtValue());// New bits are known zero.
       } else if (KnownOne.intersects(SignBit)) {