[APInt] Use isSubsetOf, intersects, and bit counting methods to reduce temporary APInts

This patch uses various APInt methods to reduce temporary APInt creation.

This should be all of the unrelated cleanups that got buried in D32376(creating a KnownBits struct) as well as some pointed out by Simon during the review of that. Plus a few improvements to use counting instead of masking.

I've left out any places where we do something like (KnownZero & KnownOne) != 0 as I plan to add a helper method to KnownBits to ask that question and didn't want to thrash that code an additional time.

Differential Revision: https://reviews.llvm.org/D32495

llvm-svn: 301338

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index febaf302ef3..5670746284e 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1376,8 +1376,7 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
   // If all valid bits in the shift amount are known zero, the first operand is
   // unchanged.
   unsigned NumValidShiftBits = Log2_32_Ceil(BitWidth);
-  APInt ShiftAmountMask = APInt::getLowBitsSet(BitWidth, NumValidShiftBits);
-  if ((KnownZero & ShiftAmountMask) == ShiftAmountMask)
+  if (KnownZero.countTrailingOnes() >= NumValidShiftBits)
     return Op0;
 
   return nullptr;
@@ -3372,7 +3371,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
       APInt LHSKnownOne(BitWidth, 0);
       computeKnownBits(LHS, LHSKnownZero, LHSKnownOne, Q.DL, /*Depth=*/0, Q.AC,
                        Q.CxtI, Q.DT);
-      if (((LHSKnownZero & *RHSVal) != 0) || ((LHSKnownOne & ~(*RHSVal)) != 0))
+      if (LHSKnownZero.intersects(*RHSVal) || !LHSKnownOne.isSubsetOf(*RHSVal))
         return Pred == ICmpInst::ICMP_EQ ? ConstantInt::getFalse(ITy)
                                          : ConstantInt::getTrue(ITy);
     }