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Move ComputeMaskedBits, MaskedValueIsZero, and ComputeNumSignBits from

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TargetLowering to SelectionDAG so that they have more convenient
access to the current DAG, in preparation for the ValueType routines
being changed from standalone functions to members of SelectionDAG for
the pre-legalize vector type changes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37704 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2007-06-22 14:59:07 +00:00
parent a8c7682939
commit ea859be53c
17 changed files with 633 additions and 620 deletions
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22
include/llvm/Target/TargetLowering.h
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@@ -494,20 +494,6 @@ public:
bool ShrinkDemandedConstant(SDOperand Op, uint64_t Demanded);
};
/// MaskedValueIsZero - Return true if 'Op & Mask' is known to be zero. We
/// use this predicate to simplify operations downstream. Op and Mask are
/// known to be the same type.
bool MaskedValueIsZero(SDOperand Op, uint64_t Mask, unsigned Depth = 0)
const;
/// ComputeMaskedBits - Determine which of the bits specified in Mask are
/// known to be either zero or one and return them in the KnownZero/KnownOne
/// bitsets. This code only analyzes bits in Mask, in order to short-circuit
/// processing. Targets can implement the computeMaskedBitsForTargetNode
/// method, to allow target nodes to be understood.
void ComputeMaskedBits(SDOperand Op, uint64_t Mask, uint64_t &KnownZero,
uint64_t &KnownOne, unsigned Depth = 0) const;
/// SimplifyDemandedBits - Look at Op. At this point, we know that only the
/// DemandedMask bits of the result of Op are ever used downstream. If we can
/// use this information to simplify Op, create a new simplified DAG node and
@@ -527,15 +513,9 @@ public:
uint64_t Mask,
uint64_t &KnownZero,
uint64_t &KnownOne,
const SelectionDAG &DAG,
unsigned Depth = 0) const;
/// ComputeNumSignBits - Return the number of times the sign bit of the
/// register is replicated into the other bits. We know that at least 1 bit
/// is always equal to the sign bit (itself), but other cases can give us
/// information. For example, immediately after an "SRA X, 2", we know that
/// the top 3 bits are all equal to each other, so we return 3.
unsigned ComputeNumSignBits(SDOperand Op, unsigned Depth = 0) const;
/// ComputeNumSignBitsForTargetNode - This method can be implemented by
/// targets that want to expose additional information about sign bits to the
/// DAG Combiner.