commit 24db6b800fcdf0b45f1e2489ec3a7fb57937f0d1
author Craig Topper <craig.topper@gmail.com> Fri Apr 28 16:58:05 2017 +0000
committer Craig Topper <craig.topper@gmail.com> Fri Apr 28 16:58:05 2017 +0000
tree 9bb13c2474c0f2d0e37ee8db12b9c27b7ebc4fa2
parent 96d6ee857653f7b155fa96e5200de3a527ec31c2

[APInt] Add clearSignBit method. Use it and setSignBit in a few places. NFCI

llvm-svn: 301656

llvm/include/llvm/ADT/APInt.h

diff --git a/llvm/include/llvm/ADT/APInt.h b/llvm/include/llvm/ADT/APInt.h
index 2491944..0338bee 100644
--- a/llvm/include/llvm/ADT/APInt.h
+++ b/llvm/include/llvm/ADT/APInt.h
@@ -1402,6 +1402,11 @@
   /// Set the given bit to 0 whose position is given as "bitPosition".
   void clearBit(unsigned bitPosition);
 
+  /// Set the sign bit to 0.
+  void clearSignBit() {
+    clearBit(BitWidth - 1);
+  }
+
   /// \brief Toggle every bit to its opposite value.
   void flipAllBits() {
     if (isSingleWord()) {

llvm/lib/Analysis/DemandedBits.cpp

diff --git a/llvm/lib/Analysis/DemandedBits.cpp b/llvm/lib/Analysis/DemandedBits.cpp
index 285339d..9f5dc53 100644
--- a/llvm/lib/Analysis/DemandedBits.cpp
+++ b/llvm/lib/Analysis/DemandedBits.cpp
@@ -181,7 +181,7 @@
         // bits, then we must keep the highest input bit.
         if ((AOut & APInt::getHighBitsSet(BitWidth, ShiftAmt))
             .getBoolValue())
-          AB.setBit(BitWidth-1);
+          AB.setSignBit();
 
         // If the shift is exact, then the low bits are not dead
         // (they must be zero).
@@ -239,7 +239,7 @@
     if ((AOut & APInt::getHighBitsSet(AOut.getBitWidth(),
                                       AOut.getBitWidth() - BitWidth))
         .getBoolValue())
-      AB.setBit(BitWidth-1);
+      AB.setSignBit();
     break;
   case Instruction::Select:
     if (OperandNo != 0)

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 2ab2e2f..dabfb8b 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2719,7 +2719,7 @@
 
     // We only know that the absolute values's MSB will be zero iff there is
     // a set bit that isn't the sign bit (otherwise it could be INT_MIN).
-    Known2.One.clearBit(BitWidth - 1);
+    Known2.One.clearSignBit();
     if (Known2.One.getBoolValue()) {
       Known.Zero = APInt::getSignMask(BitWidth);
       break;

llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
index 2e2116c..4f1f194 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
@@ -861,7 +861,7 @@
   // Find the most significant known 0 other than the sign bit.
   int BitWidth = Op0KnownZero.getBitWidth();
   APInt Op0KnownZeroTemp(Op0KnownZero);
-  Op0KnownZeroTemp.clearBit(BitWidth - 1);
+  Op0KnownZeroTemp.clearSignBit();
   int Op0ZeroPosition = BitWidth - Op0KnownZeroTemp.countLeadingZeros() - 1;
 
   int Op1OnePosition = BitWidth - Op1MaybeOne.countLeadingZeros() - 1;

llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index d3b462e..6097077 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -190,8 +190,8 @@
   Max = Known.One|UnknownBits;
 
   if (UnknownBits.isNegative()) { // Sign bit is unknown
-    Min.setBit(Min.getBitWidth()-1);
-    Max.clearBit(Max.getBitWidth()-1);
+    Min.setSignBit();
+    Max.clearSignBit();
   }
 }