[KnownBits] Add bit counting methods to KnownBits struct and use them where possible

This patch adds min/max population count, leading/trailing zero/one bit counting methods.

The min methods return answers based on bits that are known without considering unknown bits. The max methods give answers taking into account the largest count that unknown bits could give.

Differential Revision: https://reviews.llvm.org/D32931

llvm-svn: 302925

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/DemandedBits.cpp b/llvm/lib/Analysis/DemandedBits.cpp
index 9f5dc531823..c2b35b99d7c 100644
--- a/llvm/lib/Analysis/DemandedBits.cpp
+++ b/llvm/lib/Analysis/DemandedBits.cpp
@@ -118,7 +118,7 @@ void DemandedBits::determineLiveOperandBits(
           // known to be one.
           ComputeKnownBits(BitWidth, I, nullptr);
           AB = APInt::getHighBitsSet(BitWidth,
-                 std::min(BitWidth, Known.One.countLeadingZeros()+1));
+                 std::min(BitWidth, Known.countMaxLeadingZeros()+1));
         }
         break;
       case Intrinsic::cttz:
@@ -128,7 +128,7 @@ void DemandedBits::determineLiveOperandBits(
           // known to be one.
           ComputeKnownBits(BitWidth, I, nullptr);
           AB = APInt::getLowBitsSet(BitWidth,
-                 std::min(BitWidth, Known.One.countTrailingZeros()+1));
+                 std::min(BitWidth, Known.countMaxTrailingZeros()+1));
         }
         break;
       }