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llvm-mirror/lib/CodeGen/Spiller.h
Wei Mi a92f4c62f1 Recommit r265547, and r265610,r265639,r265657 on top of it, plus
two fixes with one about error verify-regalloc reported, and
another about live range update of phi after rematerialization.

r265547:
Replace analyzeSiblingValues with new algorithm to fix its compile
time issue. The patch is to solve PR17409 and its duplicates.

analyzeSiblingValues is a N x N complexity algorithm where N is
the number of siblings generated by reg splitting. Although it
causes siginificant compile time issue when N is large, it is also
important for performance since it removes redundent spills and
enables rematerialization.

To solve the compile time issue, the patch removes analyzeSiblingValues
and replaces it with lower cost alternatives containing two parts. The
first part creates a new spill hoisting method in postOptimization of
register allocation. It does spill hoisting at once after all the spills
are generated instead of inside every instance of selectOrSplit. The
second part queries the define expr of the original register for
rematerializaiton and keep it always available during register allocation
even if it is already dead. It deletes those dead instructions only in
postOptimization. With the two parts in the patch, it can remove
analyzeSiblingValues without sacrificing performance.

Patches on top of r265547:
r265610 "Fix the compare-clang diff error introduced by r265547."
r265639 "Fix the sanitizer bootstrap error in r265547."
r265657 "InlineSpiller.cpp: Escap \@ in r265547. [-Wdocumentation]"

Differential Revision: http://reviews.llvm.org/D15302
Differential Revision: http://reviews.llvm.org/D18934
Differential Revision: http://reviews.llvm.org/D18935
Differential Revision: http://reviews.llvm.org/D18936

llvm-svn: 266162
2016-04-13 03:08:27 +00:00

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1.2 KiB
C++

//===-- llvm/CodeGen/Spiller.h - Spiller -*- C++ -*------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_CODEGEN_SPILLER_H
#define LLVM_LIB_CODEGEN_SPILLER_H
namespace llvm {
class LiveRangeEdit;
class MachineFunction;
class MachineFunctionPass;
class VirtRegMap;
class LiveIntervals;
/// Spiller interface.
///
/// Implementations are utility classes which insert spill or remat code on
/// demand.
class Spiller {
virtual void anchor();
public:
virtual ~Spiller() = 0;
/// spill - Spill the LRE.getParent() live interval.
virtual void spill(LiveRangeEdit &LRE) = 0;
virtual void postOptimization(){};
};
/// Create and return a spiller that will insert spill code directly instead
/// of deferring though VirtRegMap.
Spiller *createInlineSpiller(MachineFunctionPass &pass,
MachineFunction &mf,
VirtRegMap &vrm);
}
#endif