[llvm] r200271 - [TLI] Add a new hook to TargetLowering to query the target if a load of a constant should be converted to simply the constant itself.
Juergen Ributzka
juergen at apple.com
Mon Jan 27 17:20:15 PST 2014
Author: ributzka
Date: Mon Jan 27 19:20:14 2014
New Revision: 200271
URL: http://llvm.org/viewvc/llvm-project?rev=200271&view=rev
Log:
[TLI] Add a new hook to TargetLowering to query the target if a load of a constant should be converted to simply the constant itself.
Before this patch we used getIntImmCost from TargetTransformInfo to determine if
a load of a constant should be converted to just a constant, but the threshold
for this was set to an arbitrary value. This value works well for the two
targets (X86 and ARM) that implement this target-hook, but it isn't
target-independent at all.
Now targets have the possibility to decide directly if this optimization should
be performed. The default value is set to false to preserve the current
behavior. The target hook has been moved to TargetLowering, which removed the
last use and need of TargetTransformInfo in SelectionDAG.
Modified:
llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h
llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
llvm/trunk/include/llvm/Target/TargetLowering.h
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
llvm/trunk/lib/Target/ARM/ARMISelLowering.h
llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
llvm/trunk/lib/Target/X86/X86ISelLowering.h
Modified: llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h (original)
+++ llvm/trunk/include/llvm/Analysis/TargetTransformInfo.h Mon Jan 27 19:20:14 2014
@@ -92,7 +92,6 @@ public:
enum TargetCostConstants {
TCC_Free = 0, ///< Expected to fold away in lowering.
TCC_Basic = 1, ///< The cost of a typical 'add' instruction.
- TCC_Load = 3,
TCC_Expensive = 4 ///< The cost of a 'div' instruction on x86.
};
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAG.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAG.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAG.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAG.h Mon Jan 27 19:20:14 2014
@@ -36,7 +36,6 @@ class MDNode;
class SDDbgValue;
class TargetLowering;
class TargetSelectionDAGInfo;
-class TargetTransformInfo;
class SDVTListNode : public FoldingSetNode {
friend struct FoldingSetTrait<SDVTListNode>;
@@ -169,7 +168,6 @@ void checkForCycles(const SelectionDAG *
class SelectionDAG {
const TargetMachine &TM;
const TargetSelectionDAGInfo &TSI;
- const TargetTransformInfo *TTI;
const TargetLowering *TLI;
MachineFunction *MF;
LLVMContext *Context;
@@ -269,8 +267,7 @@ public:
/// init - Prepare this SelectionDAG to process code in the given
/// MachineFunction.
///
- void init(MachineFunction &mf, const TargetTransformInfo *TTI,
- const TargetLowering *TLI);
+ void init(MachineFunction &mf, const TargetLowering *TLI);
/// clear - Clear state and free memory necessary to make this
/// SelectionDAG ready to process a new block.
@@ -281,7 +278,6 @@ public:
const TargetMachine &getTarget() const { return TM; }
const TargetLowering &getTargetLoweringInfo() const { return *TLI; }
const TargetSelectionDAGInfo &getSelectionDAGInfo() const { return TSI; }
- const TargetTransformInfo *getTargetTransformInfo() const { return TTI; }
LLVMContext *getContext() const {return Context; }
/// viewGraph - Pop up a GraphViz/gv window with the DAG rendered using 'dot'.
Modified: llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h (original)
+++ llvm/trunk/include/llvm/CodeGen/SelectionDAGISel.h Mon Jan 27 19:20:14 2014
@@ -30,7 +30,6 @@ namespace llvm {
class MachineInstr;
class TargetLowering;
class TargetLibraryInfo;
- class TargetTransformInfo;
class FunctionLoweringInfo;
class ScheduleHazardRecognizer;
class GCFunctionInfo;
@@ -43,7 +42,6 @@ class SelectionDAGISel : public MachineF
public:
TargetMachine &TM;
const TargetLibraryInfo *LibInfo;
- const TargetTransformInfo *TTI;
FunctionLoweringInfo *FuncInfo;
MachineFunction *MF;
MachineRegisterInfo *RegInfo;
Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLowering.h Mon Jan 27 19:20:14 2014
@@ -1287,6 +1287,15 @@ public:
return false;
}
+ /// \brief Return true if it is beneficial to convert a load of a constant to
+ /// just the constant itself.
+ /// On some targets it might be more efficient to use a combination of
+ /// arithmetic instructions to materialize the constant instead of loading it
+ /// from a constant pool.
+ virtual bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
+ Type *Ty) const {
+ return false;
+ }
//===--------------------------------------------------------------------===//
// Runtime Library hooks
//
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Jan 27 19:20:14 2014
@@ -18,7 +18,6 @@
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineConstantPool.h"
@@ -887,7 +886,7 @@ unsigned SelectionDAG::getEVTAlignment(E
// EntryNode could meaningfully have debug info if we can find it...
SelectionDAG::SelectionDAG(const TargetMachine &tm, CodeGenOpt::Level OL)
- : TM(tm), TSI(*tm.getSelectionDAGInfo()), TTI(0), TLI(0), OptLevel(OL),
+ : TM(tm), TSI(*tm.getSelectionDAGInfo()), TLI(0), OptLevel(OL),
EntryNode(ISD::EntryToken, 0, DebugLoc(), getVTList(MVT::Other)),
Root(getEntryNode()), NewNodesMustHaveLegalTypes(false),
UpdateListeners(0) {
@@ -895,10 +894,8 @@ SelectionDAG::SelectionDAG(const TargetM
DbgInfo = new SDDbgInfo();
}
-void SelectionDAG::init(MachineFunction &mf, const TargetTransformInfo *tti,
- const TargetLowering *tli) {
+void SelectionDAG::init(MachineFunction &mf, const TargetLowering *tli) {
MF = &mf;
- TTI = tti;
TLI = tli;
Context = &mf.getFunction()->getContext();
}
@@ -3575,9 +3572,8 @@ static SDValue getMemsetStringVal(EVT VT
// If the "cost" of materializing the integer immediate is less than the cost
// of a load, then it is cost effective to turn the load into the immediate.
- const TargetTransformInfo *TTI = DAG.getTargetTransformInfo();
- if (TTI->getIntImmCost(Val, VT.getTypeForEVT(*DAG.getContext())) <
- TargetTransformInfo::TCC_Load)
+ Type *Ty = VT.getTypeForEVT(*DAG.getContext());
+ if (TLI.shouldConvertConstantLoadToIntImm(Val, Ty))
return DAG.getConstant(Val, VT);
return SDValue(0, 0);
}
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp Mon Jan 27 19:20:14 2014
@@ -20,7 +20,6 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/CFG.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/GCMetadata.h"
@@ -400,7 +399,6 @@ bool SelectionDAGISel::runOnMachineFunct
RegInfo = &MF->getRegInfo();
AA = &getAnalysis<AliasAnalysis>();
LibInfo = &getAnalysis<TargetLibraryInfo>();
- TTI = getAnalysisIfAvailable<TargetTransformInfo>();
GFI = Fn.hasGC() ? &getAnalysis<GCModuleInfo>().getFunctionInfo(Fn) : 0;
TargetSubtargetInfo &ST =
@@ -418,7 +416,7 @@ bool SelectionDAGISel::runOnMachineFunct
SplitCriticalSideEffectEdges(const_cast<Function&>(Fn), this);
- CurDAG->init(*MF, TTI, TLI);
+ CurDAG->init(*MF, TLI);
FuncInfo->set(Fn, *MF);
if (UseMBPI && OptLevel != CodeGenOpt::None)
Modified: llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp Mon Jan 27 19:20:14 2014
@@ -11199,3 +11199,15 @@ bool ARMTargetLowering::getTgtMemIntrins
return false;
}
+
+/// \brief Returns true if it is beneficial to convert a load of a constant
+/// to just the constant itself.
+bool ARMTargetLowering::shouldConvertConstantLoadToIntImm(const APInt &Imm,
+ Type *Ty) const {
+ assert(Ty->isIntegerTy());
+
+ unsigned Bits = Ty->getPrimitiveSizeInBits();
+ if (Bits == 0 || Bits > 32)
+ return false;
+ return true;
+}
Modified: llvm/trunk/lib/Target/ARM/ARMISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelLowering.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelLowering.h (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelLowering.h Mon Jan 27 19:20:14 2014
@@ -385,6 +385,12 @@ namespace llvm {
virtual bool getTgtMemIntrinsic(IntrinsicInfo &Info,
const CallInst &I,
unsigned Intrinsic) const;
+
+ /// \brief Returns true if it is beneficial to convert a load of a constant
+ /// to just the constant itself.
+ virtual bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
+ Type *Ty) const;
+
protected:
std::pair<const TargetRegisterClass*, uint8_t>
findRepresentativeClass(MVT VT) const;
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Mon Jan 27 19:20:14 2014
@@ -3570,6 +3570,18 @@ bool X86TargetLowering::isFPImmLegal(con
return false;
}
+/// \brief Returns true if it is beneficial to convert a load of a constant
+/// to just the constant itself.
+bool X86TargetLowering::shouldConvertConstantLoadToIntImm(const APInt &Imm,
+ Type *Ty) const {
+ assert(Ty->isIntegerTy());
+
+ unsigned BitSize = Ty->getPrimitiveSizeInBits();
+ if (BitSize == 0 || BitSize > 64)
+ return false;
+ return true;
+}
+
/// isUndefOrInRange - Return true if Val is undef or if its value falls within
/// the specified range (L, H].
static bool isUndefOrInRange(int Val, int Low, int Hi) {
Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.h?rev=200271&r1=200270&r2=200271&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.h (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.h Mon Jan 27 19:20:14 2014
@@ -764,6 +764,11 @@ namespace llvm {
return isTargetFTOL() && VT == MVT::i64;
}
+ /// \brief Returns true if it is beneficial to convert a load of a constant
+ /// to just the constant itself.
+ virtual bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
+ Type *Ty) const;
+
/// createFastISel - This method returns a target specific FastISel object,
/// or null if the target does not support "fast" ISel.
virtual FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
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