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Rewrite the comments for RegsForValue and its members, and 

reorder some of the members for clarity.

llvm-svn: 50365
This commit is contained in:
Dan Gohman 2008-04-28 18:10:39 +00:00
parent 6065ef6b9b
commit 80c692d439
1 changed files with 30 additions and 20 deletions
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50
llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
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@ -114,46 +114,56 @@ static void ComputeValueVTs(const TargetLowering &TLI, const Type *Ty,
}
namespace {
/// RegsForValue - This struct represents the physical registers that a
/// particular value is assigned and the type information about the value.
/// This is needed because values can be promoted into larger registers and
/// expanded into multiple smaller registers than the value.
/// RegsForValue - This struct represents the registers (physical or virtual)
/// that a particular set of values is assigned, and the type information about
/// the value. The most common situation is to represent one value at a time,
/// but struct or array values are handled element-wise as multiple values.
/// The splitting of aggregates is performed recursively, so that we never
/// have aggregate-typed registers. The values at this point do not necessarily
/// have legal types, so each value may require one or more registers of some
/// legal type.
///
struct VISIBILITY_HIDDEN RegsForValue {
/// TLI - The TargetLowering object.
///
const TargetLowering *TLI;
/// Regs - This list holds the register (for legal and promoted values)
/// or register set (for expanded values) that the value should be assigned
/// to.
SmallVector<unsigned, 4> Regs;
/// ValueVTs - The value types of the values, which may not be legal, and
/// may need be promoted or synthesized from one or more registers.
///
SmallVector<MVT::ValueType, 4> ValueVTs;
/// RegVTs - The value types of the registers. This is the same size
/// as ValueVTs; every register contributing to a given value must
/// have the same type. When Regs contains all virtual registers, the
/// contents of RegVTs is redundant with TLI's getRegisterType member
/// function, however when Regs contains physical registers, it is
/// necessary to have a separate record of the types.
/// RegVTs - The value types of the registers. This is the same size as
/// ValueVTs and it records, for each value, what the type of the assigned
/// register or registers are. (Individual values are never synthesized
/// from more than one type of register.)
///
/// With virtual registers, the contents of RegVTs is redundant with TLI's
/// getRegisterType member function, however when with physical registers
/// it is necessary to have a separate record of the types.
///
SmallVector<MVT::ValueType, 4> RegVTs;
/// ValueVTs - The value types of the values, which may be promoted
/// or synthesized from one or more registers.
SmallVector<MVT::ValueType, 4> ValueVTs;
/// Regs - This list holds the registers assigned to the values.
/// Each legal or promoted value requires one register, and each
/// expanded value requires multiple registers.
///
SmallVector<unsigned, 4> Regs;
RegsForValue() : TLI(0) {}
RegsForValue(const TargetLowering &tli,
unsigned Reg, MVT::ValueType regvt, MVT::ValueType valuevt)
: TLI(&tli), Regs(1, Reg), RegVTs(1, regvt), ValueVTs(1, valuevt) {}
: TLI(&tli), ValueVTs(1, valuevt), RegVTs(1, regvt), Regs(1, Reg) {}
RegsForValue(const TargetLowering &tli,
const SmallVector<unsigned, 4> &regs,
MVT::ValueType regvt, MVT::ValueType valuevt)
: TLI(&tli), Regs(regs), RegVTs(1, regvt), ValueVTs(1, valuevt) {}
: TLI(&tli), ValueVTs(1, valuevt), RegVTs(1, regvt), Regs(regs) {}
RegsForValue(const TargetLowering &tli,
const SmallVector<unsigned, 4> &regs,
const SmallVector<MVT::ValueType, 4> &regvts,
const SmallVector<MVT::ValueType, 4> &valuevts)
: TLI(&tli), Regs(regs), RegVTs(regvts), ValueVTs(valuevts) {}
: TLI(&tli), ValueVTs(valuevts), RegVTs(regvts), Regs(regs) {}
RegsForValue(const TargetLowering &tli,
unsigned Reg, const Type *Ty) : TLI(&tli) {
ComputeValueVTs(tli, Ty, ValueVTs);