[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, 4 insertions, 4 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
index ae01ea477bb..7141e77fcd2 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelDAGToDAG.cpp
@@ -1865,7 +1865,7 @@ static void getUsefulBitsFromBitfieldMoveOpd(SDValue Op, APInt &UsefulBits,
     OpUsefulBits = OpUsefulBits.shl(OpUsefulBits.getBitWidth() - Imm);
     getUsefulBits(Op, OpUsefulBits, Depth + 1);
     // The interesting part was at zero in the argument
-    OpUsefulBits = OpUsefulBits.lshr(OpUsefulBits.getBitWidth() - Imm);
+    OpUsefulBits.lshrInPlace(OpUsefulBits.getBitWidth() - Imm);
   }
 
   UsefulBits &= OpUsefulBits;
@@ -1894,13 +1894,13 @@ static void getUsefulBitsFromOrWithShiftedReg(SDValue Op, APInt &UsefulBits,
     uint64_t ShiftAmt = AArch64_AM::getShiftValue(ShiftTypeAndValue);
     Mask = Mask.shl(ShiftAmt);
     getUsefulBits(Op, Mask, Depth + 1);
-    Mask = Mask.lshr(ShiftAmt);
+    Mask.lshrInPlace(ShiftAmt);
   } else if (AArch64_AM::getShiftType(ShiftTypeAndValue) == AArch64_AM::LSR) {
     // Shift Right
     // We do not handle AArch64_AM::ASR, because the sign will change the
     // number of useful bits
     uint64_t ShiftAmt = AArch64_AM::getShiftValue(ShiftTypeAndValue);
-    Mask = Mask.lshr(ShiftAmt);
+    Mask.lshrInPlace(ShiftAmt);
     getUsefulBits(Op, Mask, Depth + 1);
     Mask = Mask.shl(ShiftAmt);
   } else
@@ -1954,7 +1954,7 @@ static void getUsefulBitsFromBFM(SDValue Op, SDValue Orig, APInt &UsefulBits,
     if (Op.getOperand(1) == Orig) {
       // Copy the bits from the result to the zero bits.
       Mask = ResultUsefulBits & OpUsefulBits;
-      Mask = Mask.lshr(LSB);
+      Mask.lshrInPlace(LSB);
     }
 
     if (Op.getOperand(0) == Orig)