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include/llvm/IR/InvariantInfo.h

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//===-------- llvm/InvariantInfo.h - invariant_start/end info ---*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines properties for handling invariant_start/end instructions
// for purposes of load elimination.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_INVARIANTINFO_H
#define LLVM_IR_INVARIANTINFO_H
#include "llvm/ADT/DenseMap.h"
namespace llvm {
class Value;
class DataLayout;
class IntrinsicInst;
nlewyckyUnsubmitted
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Alphabetize.

nlewycky: Alphabetize.
/// PreservedInvariantInfo -- A data structure to mark and access processed
/// invariant intrinsic calls.
class InvariantInfo {
nlewyckyUnsubmitted
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One side says "PreservedInvariantInfo" the other side says "InvariantInfo". Just remove the class name from the comment, that style is pre-style guide.

Also, "a data structure to mark and access processed invariant intrinsic calls"? I don't think that tells me what it does or what it's for. Is it a cache of invariant intrinsics that pertain to a given Value?

nlewycky: One side says "PreservedInvariantInfo" the other side says "InvariantInfo". Just remove the…
sanjoyUnsubmitted
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Please add some high level comments describing how this is supposed to be used.

sanjoy: Please add some high level comments describing how this is supposed to be used.
lvoufoAuthorUnsubmitted
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Ok.

lvoufo: Ok.
/// \brief A mapping of each 'writeonce' allocated memory (via a
sanjoyUnsubmitted
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Please add some comments on how you deal with passes RAUW'ing or erasing values.

sanjoy: Please add some comments on how you deal with passes RAUW'ing or erasing values.
lvoufoAuthorUnsubmitted
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Ok.

lvoufo: Ok.
nlewyckyUnsubmitted
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"writeonce" is not defined anywhere?

nlewycky: "writeonce" is not defined anywhere?
/// GlobalVariable or AllocaInst instance) to its matching intrisic_start
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Typo in "intrisic_start"

nlewycky: Typo in "intrisic_start"
/// call. This is to be used by GVN, InstCombine, GlobalOpt and BasicAA
/// to process invariant intrinsics for purposes of eliminating redundant
/// load instructions.
DenseMap<Value *, IntrinsicInst *> InvariantMarkers;
public:
/// \brief Access the 'InvariantMarkers' mapping to extract invariant_start
/// instruction that is associated with the given Address.
IntrinsicInst *GetStartInstruction(const Value *Addr) const;
/// \brief Add an entry to the 'InvariantMarkers' mapping.
void SetStartInstruction(Value *Addr, IntrinsicInst *IStart);
};
/// PreservedInvariantInfo -- Information processed from invariant intrinsics,
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Remove struct name from comment.

nlewycky: Remove struct name from comment.
/// for a given query instruction.
struct PreservedInvariantInfo {
IntrinsicInst *II;
Value *LoadedAddr;
InvariantInfo &InvInfo;
PreservedInvariantInfo(Value *Query, const DataLayout &DL,
InvariantInfo &InvInfo);
};
/// PreserveInvariantInfo -- An RAII object to save and restore information
sanjoyUnsubmitted
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Please document these functions.

sanjoy: Please document these functions.
lvoufoAuthorUnsubmitted
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Do you mean in addition to the documentation of its implementation in lib/IR/InvariantInfo.cpp ?

lvoufo: Do you mean in addition to the documentation of its implementation in lib/IR/InvariantInfo.cpp ?
sanjoyUnsubmitted
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Never mind, I just saw the docs in the implementation file. :)

The doxygen comments are typically put in the header.

sanjoy: Never mind, I just saw the docs in the implementation file. :) The doxygen comments are…
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No problem. I just figured it would be more legible to have the detailed documentation right next to the implementation. I can add some high-level comments on the prototypes too if it help.

lvoufo: No problem. I just figured it would be more legible to have the detailed documentation right…
/// from processed invariant intrinsics.
class PreserveInvariantInfo {
nlewyckyUnsubmitted
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Hold on, you have one struct PreservedInvariantInfo and one class PreserveInvariantInfo? Please rename one of them.

nlewycky: Hold on, you have one struct PreservedInvariantInfo and one class PreserveInvariantInfo? Please…
PreservedInvariantInfo Preserved;
void CheckPreservedInfo() const;
public:
PreserveInvariantInfo(PreservedInvariantInfo Info);
~PreserveInvariantInfo();
};
/// \brief Process invariant_start/end intrinsics: Mark addresses as "within
/// an invariant range" specified by the given intrinsic call.
bool processInvariantIntrinsic(IntrinsicInst *II, InvariantInfo &InvInfo);
/// \brief Handle invariant_start/end intrinsics when scanning intructions
/// backward to either find available loads or look for pointer dependencies
/// from a given query instruction, based on preserved invariant info.
bool BackwardScanInvariantIntrinsic(const IntrinsicInst *II,
const PreservedInvariantInfo &Preserved,
InvariantInfo &InvInfo);
} // End llvm namespace
#endif