Commit 7dbba337 authored by Johannes Doerfert's avatar Johannes Doerfert
Browse files

[GlobalOpt][FIX] Do not embed initializers into AS!=0 globals 

Not all address spaces support initializers for globals and we can
therefore not set them without checking if they are allowed. This
patch adds a hook into TTI to check if an AS allows non-undef
initializers. We disable it for all but address space 0 by default,
NVPTX and AMDGPU targets allow all but address space 3.

Reviewed By: tra

Differential Revision: https://reviews.llvm.org/D109337
parent ca134c39

llvm/include/llvm/Analysis/TargetTransformInfo.h

+11 −0
Original line number Diff line number Diff line
@@ -383,6 +383,10 @@ public: 


  bool isNoopAddrSpaceCast(unsigned FromAS, unsigned ToAS) const;



  /// Return true if globals in this address space can have initializers other

  /// than `undef`.

  bool canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const;



  unsigned getAssumedAddrSpace(const Value *V) const;



  /// Rewrite intrinsic call \p II such that \p OldV will be replaced with \p
@@ -1457,6 +1461,8 @@ public: 
  virtual bool collectFlatAddressOperands(SmallVectorImpl<int> &OpIndexes,

                                          Intrinsic::ID IID) const = 0;

  virtual bool isNoopAddrSpaceCast(unsigned FromAS, unsigned ToAS) const = 0;

  virtual bool

  canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const = 0;

  virtual unsigned getAssumedAddrSpace(const Value *V) const = 0;

  virtual Value *rewriteIntrinsicWithAddressSpace(IntrinsicInst *II,

                                                  Value *OldV,
@@ -1782,6 +1788,11 @@ public: 
    return Impl.isNoopAddrSpaceCast(FromAS, ToAS);

  }



  bool

  canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const override {

    return Impl.canHaveNonUndefGlobalInitializerInAddressSpace(AS);

  }



  unsigned getAssumedAddrSpace(const Value *V) const override {

    return Impl.getAssumedAddrSpace(V);

  }

llvm/include/llvm/Analysis/TargetTransformInfoImpl.h

+3 −0
Original line number Diff line number Diff line
@@ -105,6 +105,9 @@ public: 
  }



  bool isNoopAddrSpaceCast(unsigned, unsigned) const { return false; }

  bool canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const {

    return AS == 0;

  };



  unsigned getAssumedAddrSpace(const Value *V) const { return -1; }

llvm/include/llvm/Transforms/Utils/GlobalStatus.h

+12 −3
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#ifndef LLVM_TRANSFORMS_UTILS_GLOBALSTATUS_H

#define LLVM_TRANSFORMS_UTILS_GLOBALSTATUS_H



#include "llvm/IR/Instructions.h"

#include "llvm/Support/AtomicOrdering.h"



namespace llvm {
@@ -45,7 +46,7 @@ struct GlobalStatus { 


    /// This global is stored to, but only its initializer and one other value

    /// is ever stored to it.  If this global isStoredOnce, we track the value

    /// stored to it in StoredOnceValue below.  This is only tracked for scalar

    /// stored to it via StoredOnceStore below.  This is only tracked for scalar

    /// globals.

    StoredOnce,
@@ -55,8 +56,16 @@ struct GlobalStatus { 
  } StoredType = NotStored;



  /// If only one value (besides the initializer constant) is ever stored to

  /// this global, keep track of what value it is.

  Value *StoredOnceValue = nullptr;

  /// this global, keep track of what value it is via the store instruction.

  const StoreInst *StoredOnceStore = nullptr;



  /// If only one value (besides the initializer constant) is ever stored to

  /// this global return the stored value.

  Value *getStoredOnceValue() const {

    return (StoredType == StoredOnce && StoredOnceStore)

               ? StoredOnceStore->getOperand(0)

               : nullptr;

  }



  /// These start out null/false.  When the first accessing function is noticed,

  /// it is recorded. When a second different accessing function is noticed,

llvm/lib/Analysis/TargetTransformInfo.cpp

+5 −0
Original line number Diff line number Diff line
@@ -259,6 +259,11 @@ bool TargetTransformInfo::isNoopAddrSpaceCast(unsigned FromAS, 
  return TTIImpl->isNoopAddrSpaceCast(FromAS, ToAS);

}



bool TargetTransformInfo::canHaveNonUndefGlobalInitializerInAddressSpace(

    unsigned AS) const {

  return TTIImpl->canHaveNonUndefGlobalInitializerInAddressSpace(AS);

}



unsigned TargetTransformInfo::getAssumedAddrSpace(const Value *V) const {

  return TTIImpl->getAssumedAddrSpace(V);

}

llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.h

+6 −0
Original line number Diff line number Diff line
@@ -182,6 +182,12 @@ public: 


  bool collectFlatAddressOperands(SmallVectorImpl<int> &OpIndexes,

                                  Intrinsic::ID IID) const;



  bool canHaveNonUndefGlobalInitializerInAddressSpace(unsigned AS) const {

    return AS != AMDGPUAS::LOCAL_ADDRESS && AS != AMDGPUAS::REGION_ADDRESS &&

           AS != AMDGPUAS::PRIVATE_ADDRESS;

  }



  Value *rewriteIntrinsicWithAddressSpace(IntrinsicInst *II, Value *OldV,

                                          Value *NewV) const;