Author: baldrick
Date: Sat Dec 1 01:51:45 2007
New Revision: 44487
URL: http://llvm.org/viewvc/llvm-project?rev=44487&view=rev
Log:
Integrate the readonly/readnone logic more deeply
into alias analysis. This meant updating the API
which now has versions of the getModRefBehavior,
doesNotAccessMemory and onlyReadsMemory methods
which take a callsite parameter. These should be
used unless the callsite is not known, since in
general they can do a better job than the versions
that take a function. Also, users should no longer
call the version of getModRefBehavior that takes
both a function and a callsite. To reduce the
chance of misuse it is now protected.
Modified:
llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
llvm/trunk/lib/Analysis/AliasAnalysis.cpp
llvm/trunk/lib/Analysis/AliasAnalysisCounter.cpp
llvm/trunk/lib/Analysis/AliasSetTracker.cpp
llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp
llvm/trunk/lib/Analysis/LoadValueNumbering.cpp
llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
llvm/trunk/lib/Transforms/Scalar/ADCE.cpp
llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
llvm/trunk/lib/Transforms/Scalar/GVN.cpp
llvm/trunk/lib/Transforms/Scalar/LICM.cpp
Modified: llvm/trunk/include/llvm/Analysis/AliasAnalysis.h
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/AliasAnalysis.h?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/AliasAnalysis.h (original)
+++ llvm/trunk/include/llvm/Analysis/AliasAnalysis.h Sat Dec 1 01:51:45 2007
@@ -186,40 +186,57 @@
};
};
- /// getModRefBehavior - Return the behavior of the specified function if
- /// called from the specified call site. The call site may be null in which
- /// case the most generic behavior of this function should be returned.
- virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
- std::vector<PointerAccessInfo> *Info = 0);
-
- /// doesNotAccessMemory - If the specified function is known to never read or
- /// write memory, return true. If the function only reads from
known-constant
- /// memory, it is also legal to return true. Functions that unwind the stack
- /// are not legal for this predicate.
- ///
- /// Many optimizations (such as CSE and LICM) can be performed on calls to
it,
- /// without worrying about aliasing properties, and many functions have this
- /// property (e.g. 'sin' and 'cos').
+ /// getModRefBehavior - Return the behavior when calling the given call site.
+ ModRefBehavior getModRefBehavior(CallSite CS,
+ std::vector<PointerAccessInfo> *Info = 0);
+
+ /// getModRefBehavior - Return the behavior when calling the given function.
+ /// For use when the call site is not known.
+ ModRefBehavior getModRefBehavior(Function *F,
+ std::vector<PointerAccessInfo> *Info = 0);
+
+ /// doesNotAccessMemory - If the specified call is known to never read or
+ /// write memory, return true. If the call only reads from known-constant
+ /// memory, it is also legal to return true. Calls that unwind the stack
+ /// are legal for this predicate.
+ ///
+ /// Many optimizations (such as CSE and LICM) can be performed on such calls
+ /// without worrying about aliasing properties, and many calls have this
+ /// property (e.g. calls to 'sin' and 'cos').
///
/// This property corresponds to the GCC 'const' attribute.
///
+ bool doesNotAccessMemory(CallSite CS) {
+ return getModRefBehavior(CS) == DoesNotAccessMemory;
+ }
+
+ /// doesNotAccessMemory - If the specified function is known to never read or
+ /// write memory, return true. For use when the call site is not known.
+ ///
bool doesNotAccessMemory(Function *F) {
- return getModRefBehavior(F, CallSite()) == DoesNotAccessMemory;
+ return getModRefBehavior(F) == DoesNotAccessMemory;
}
- /// onlyReadsMemory - If the specified function is known to only read from
- /// non-volatile memory (or not access memory at all), return true.
Functions
- /// that unwind the stack are not legal for this predicate.
+ /// onlyReadsMemory - If the specified call is known to only read from
+ /// non-volatile memory (or not access memory at all), return true. Calls
+ /// that unwind the stack are legal for this predicate.
///
/// This property allows many common optimizations to be performed in the
/// absence of interfering store instructions, such as CSE of strlen calls.
///
/// This property corresponds to the GCC 'pure' attribute.
///
+ bool onlyReadsMemory(CallSite CS) {
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ return MRB == DoesNotAccessMemory || MRB == OnlyReadsMemory;
+ }
+
+ /// onlyReadsMemory - If the specified function is known to only read from
+ /// non-volatile memory (or not access memory at all), return true. For use
+ /// when the call site is not known.
+ ///
bool onlyReadsMemory(Function *F) {
- /// FIXME: If the analysis returns more precise info, we can reduce it to
- /// this.
- ModRefBehavior MRB = getModRefBehavior(F, CallSite());
+ ModRefBehavior MRB = getModRefBehavior(F);
return MRB == DoesNotAccessMemory || MRB == OnlyReadsMemory;
}
@@ -250,6 +267,14 @@
///
virtual bool hasNoModRefInfoForCalls() const;
+protected:
+ /// getModRefBehavior - Return the behavior of the specified function if
+ /// called from the specified call site. The call site may be null in which
+ /// case the most generic behavior of this function should be returned.
+ virtual ModRefBehavior getModRefBehavior(Function *F, CallSite CS,
+ std::vector<PointerAccessInfo> *Info = 0);
+
+public:
/// Convenience functions...
ModRefResult getModRefInfo(LoadInst *L, Value *P, unsigned Size);
ModRefResult getModRefInfo(StoreInst *S, Value *P, unsigned Size);
Modified: llvm/trunk/lib/Analysis/AliasAnalysis.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasAnalysis.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasAnalysis.cpp Sat Dec 1 01:51:45 2007
@@ -27,6 +27,7 @@
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Pass.h"
#include "llvm/BasicBlock.h"
+#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
@@ -112,16 +113,40 @@
return pointsToConstantMemory(P) ? NoModRef : Mod;
}
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(CallSite CS,
+ std::vector<PointerAccessInfo> *Info) {
+ if (CS.paramHasAttr(0, ParamAttr::ReadNone))
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = UnknownModRefBehavior;
+ if (Function *F = CS.getCalledFunction())
+ MRB = getModRefBehavior(F, CS, Info);
+ if (MRB != DoesNotAccessMemory && CS.paramHasAttr(0, ParamAttr::ReadOnly))
+ return OnlyReadsMemory;
+ return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+ std::vector<PointerAccessInfo> *Info) {
+ if (F->paramHasAttr(0, ParamAttr::ReadNone))
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = getModRefBehavior(F, CallSite(), Info);
+ if (MRB != DoesNotAccessMemory && F->paramHasAttr(0, ParamAttr::ReadOnly))
+ return OnlyReadsMemory;
+ return MRB;
+}
+
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
ModRefResult Mask = ModRef;
- if (Function *F = CS.getCalledFunction()) {
- ModRefBehavior MRB = getModRefBehavior(F, CallSite());
- if (MRB == OnlyReadsMemory)
- Mask = Ref;
- else if (MRB == DoesNotAccessMemory)
- return NoModRef;
- }
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ if (MRB == OnlyReadsMemory)
+ Mask = Ref;
+ else if (MRB == DoesNotAccessMemory)
+ return NoModRef;
if (!AA) return Mask;
Modified: llvm/trunk/lib/Analysis/AliasAnalysisCounter.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasAnalysisCounter.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasAnalysisCounter.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasAnalysisCounter.cpp Sat Dec 1 01:51:45 2007
@@ -89,9 +89,15 @@
bool pointsToConstantMemory(const Value *P) {
return getAnalysis<AliasAnalysis>().pointsToConstantMemory(P);
}
+ bool doesNotAccessMemory(CallSite CS) {
+ return getAnalysis<AliasAnalysis>().doesNotAccessMemory(CS);
+ }
bool doesNotAccessMemory(Function *F) {
return getAnalysis<AliasAnalysis>().doesNotAccessMemory(F);
}
+ bool onlyReadsMemory(CallSite CS) {
+ return getAnalysis<AliasAnalysis>().onlyReadsMemory(CS);
+ }
bool onlyReadsMemory(Function *F) {
return getAnalysis<AliasAnalysis>().onlyReadsMemory(F);
}
Modified: llvm/trunk/lib/Analysis/AliasSetTracker.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/AliasSetTracker.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/AliasSetTracker.cpp (original)
+++ llvm/trunk/lib/Analysis/AliasSetTracker.cpp Sat Dec 1 01:51:45 2007
@@ -114,15 +114,13 @@
void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
CallSites.push_back(CS);
- if (Function *F = CS.getCalledFunction()) {
- AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(F, CS);
- if (Behavior == AliasAnalysis::DoesNotAccessMemory)
- return;
- else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
- AliasTy = MayAlias;
- AccessTy |= Refs;
- return;
- }
+ AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(CS);
+ if (Behavior == AliasAnalysis::DoesNotAccessMemory)
+ return;
+ else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
+ AliasTy = MayAlias;
+ AccessTy |= Refs;
+ return;
}
// FIXME: This should use mod/ref information to make this not suck so bad
@@ -166,9 +164,8 @@
}
bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
- if (Function *F = CS.getCalledFunction())
- if (AA.doesNotAccessMemory(F))
- return false;
+ if (AA.doesNotAccessMemory(CS))
+ return false;
if (AA.hasNoModRefInfoForCalls())
return true;
@@ -297,9 +294,8 @@
bool AliasSetTracker::add(CallSite CS) {
- if (Function *F = CS.getCalledFunction())
- if (AA.doesNotAccessMemory(F))
- return true; // doesn't alias anything
+ if (AA.doesNotAccessMemory(CS))
+ return true; // doesn't alias anything
AliasSet *AS = findAliasSetForCallSite(CS);
if (!AS) {
@@ -419,9 +415,8 @@
}
bool AliasSetTracker::remove(CallSite CS) {
- if (Function *F = CS.getCalledFunction())
- if (AA.doesNotAccessMemory(F))
- return false; // doesn't alias anything
+ if (AA.doesNotAccessMemory(CS))
+ return false; // doesn't alias anything
AliasSet *AS = findAliasSetForCallSite(CS);
if (!AS) return false;
@@ -455,13 +450,10 @@
// If this is a call instruction, remove the callsite from the appropriate
// AliasSet.
CallSite CS = CallSite::get(PtrVal);
- if (CS.getInstruction()) {
- Function *F = CS.getCalledFunction();
- if (!F || !AA.doesNotAccessMemory(F)) {
+ if (CS.getInstruction())
+ if (!AA.doesNotAccessMemory(CS))
if (AliasSet *AS = findAliasSetForCallSite(CS))
AS->removeCallSite(CS);
- }
- }
// First, look up the PointerRec for this pointer.
hash_map<Value*, AliasSet::PointerRec>::iterator I = PointerMap.find(PtrVal);
Modified: llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/BasicAliasAnalysis.cpp Sat Dec 1 01:51:45 2007
@@ -839,11 +839,6 @@
return UnknownModRefBehavior;
}
- if (F->paramHasAttr(0, ParamAttr::ReadNone))
- return DoesNotAccessMemory;
- if (F->paramHasAttr(0, ParamAttr::ReadOnly))
- return OnlyReadsMemory;
-
return UnknownModRefBehavior;
}
Modified: llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp (original)
+++ llvm/trunk/lib/Analysis/IPA/GlobalsModRef.cpp Sat Dec 1 01:51:45 2007
@@ -394,7 +394,7 @@
// Okay, if we can't say anything about it, maybe some other alias
// analysis can.
ModRefBehavior MRB =
- AliasAnalysis::getModRefBehavior(Callee, CallSite());
+ AliasAnalysis::getModRefBehavior(Callee);
if (MRB != DoesNotAccessMemory) {
// FIXME: could make this more aggressive for functions that just
// read memory. We should just say they read all globals.
Modified: llvm/trunk/lib/Analysis/LoadValueNumbering.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/LoadValueNumbering.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/LoadValueNumbering.cpp (original)
+++ llvm/trunk/lib/Analysis/LoadValueNumbering.cpp Sat Dec 1 01:51:45 2007
@@ -148,7 +148,7 @@
Function *CF = CI->getCalledFunction();
if (CF == 0) return; // Indirect call.
AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
- AliasAnalysis::ModRefBehavior MRB = AA.getModRefBehavior(CF, CI);
+ AliasAnalysis::ModRefBehavior MRB = AA.getModRefBehavior(CI);
if (MRB != AliasAnalysis::DoesNotAccessMemory &&
MRB != AliasAnalysis::OnlyReadsMemory)
return; // Nothing we can do for now.
@@ -227,8 +227,7 @@
CantEqual = true;
break;
} else if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (CI->getCalledFunction() == 0 ||
- !AA.onlyReadsMemory(CI->getCalledFunction())) {
+ if (!AA.onlyReadsMemory(CI)) {
CantEqual = true;
break;
}
Modified: llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp (original)
+++ llvm/trunk/lib/Analysis/MemoryDependenceAnalysis.cpp Sat Dec 1 01:51:45
2007
@@ -94,11 +94,9 @@
// FreeInsts erase the entire structure
pointerSize = ~0UL;
- } else if (CallSite::get(QI).getInstruction() != 0 &&
- cast<CallInst>(QI)->getCalledFunction()) {
+ } else if (isa<CallInst>(QI)) {
AliasAnalysis::ModRefBehavior result =
-
AA.getModRefBehavior(cast<CallInst>(QI)->getCalledFunction(),
- CallSite::get(QI));
+ AA.getModRefBehavior(CallSite::get(QI));
if (result != AliasAnalysis::DoesNotAccessMemory &&
result != AliasAnalysis::OnlyReadsMemory) {
if (!start && !block) {
Modified: llvm/trunk/lib/Transforms/Scalar/ADCE.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ADCE.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ADCE.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ADCE.cpp Sat Dec 1 01:51:45 2007
@@ -198,8 +198,7 @@
for (BasicBlock::iterator II = BB->begin(), EI = BB->end(); II != EI; ) {
Instruction *I = II++;
if (CallInst *CI = dyn_cast<CallInst>(I)) {
- Function *F = CI->getCalledFunction();
- if (F && AA.onlyReadsMemory(F)) {
+ if (AA.onlyReadsMemory(CI)) {
if (CI->use_empty()) {
BB->getInstList().erase(CI);
++NumCallRemoved;
Modified: llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/DeadStoreElimination.cpp Sat Dec 1
01:51:45 2007
@@ -306,8 +306,7 @@
// If this call does not access memory, it can't
// be undeadifying any of our pointers.
CallSite CS = CallSite::get(BBI);
- if (CS.getCalledFunction() &&
- AA.doesNotAccessMemory(CS.getCalledFunction()))
+ if (AA.doesNotAccessMemory(CS))
continue;
unsigned modRef = 0;
Modified: llvm/trunk/lib/Transforms/Scalar/GVN.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/GVN.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/GVN.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/GVN.cpp Sat Dec 1 01:51:45 2007
@@ -341,8 +341,7 @@
uint32_t ValueTable::hash_operand(Value* v) {
if (CallInst* CI = dyn_cast<CallInst>(v))
- if (CI->getCalledFunction() &&
- !AA->doesNotAccessMemory(CI->getCalledFunction()))
+ if (!AA->doesNotAccessMemory(CI))
return nextValueNumber++;
return lookup_or_add(v);
@@ -485,9 +484,7 @@
return VI->second;
if (CallInst* C = dyn_cast<CallInst>(V)) {
- if (C->getCalledFunction() &&
- (AA->doesNotAccessMemory(C->getCalledFunction()) ||
- AA->onlyReadsMemory(C->getCalledFunction()))) {
+ if (AA->onlyReadsMemory(C)) { // includes doesNotAccessMemory
Expression e = create_expression(C);
DenseMap<Expression, uint32_t>::iterator EI =
expressionNumbering.find(e);
@@ -1051,8 +1048,7 @@
if (CallInst* CI = dyn_cast<CallInst>(I)) {
AliasAnalysis& AA = getAnalysis<AliasAnalysis>();
- if (CI->getCalledFunction() &&
- !AA.doesNotAccessMemory(CI->getCalledFunction())) {
+ if (!AA.doesNotAccessMemory(CI)) {
MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
if (cast<Instruction>(repl)->getParent() != CI->getParent() ||
MD.getDependency(CI) != MD.getDependency(cast<CallInst>(repl))) {
Modified: llvm/trunk/lib/Transforms/Scalar/LICM.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LICM.cpp?rev=44487&r1=44486&r2=44487&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LICM.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LICM.cpp Sat Dec 1 01:51:45 2007
@@ -375,24 +375,22 @@
return !pointerInvalidatedByLoop(LI->getOperand(0), Size);
} else if (CallInst *CI = dyn_cast<CallInst>(&I)) {
// Handle obvious cases efficiently.
- if (Function *Callee = CI->getCalledFunction()) {
- AliasAnalysis::ModRefBehavior Behavior =AA->getModRefBehavior(Callee,
CI);
- if (Behavior == AliasAnalysis::DoesNotAccessMemory)
- return true;
- else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
- // If this call only reads from memory and there are no writes to
memory
- // in the loop, we can hoist or sink the call as appropriate.
- bool FoundMod = false;
- for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
- I != E; ++I) {
- AliasSet &AS = *I;
- if (!AS.isForwardingAliasSet() && AS.isMod()) {
- FoundMod = true;
- break;
- }
+ AliasAnalysis::ModRefBehavior Behavior = AA->getModRefBehavior(CI);
+ if (Behavior == AliasAnalysis::DoesNotAccessMemory)
+ return true;
+ else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
+ // If this call only reads from memory and there are no writes to memory
+ // in the loop, we can hoist or sink the call as appropriate.
+ bool FoundMod = false;
+ for (AliasSetTracker::iterator I = CurAST->begin(), E = CurAST->end();
+ I != E; ++I) {
+ AliasSet &AS = *I;
+ if (!AS.isForwardingAliasSet() && AS.isMod()) {
+ FoundMod = true;
+ break;
}
- if (!FoundMod) return true;
}
+ if (!FoundMod) return true;
}
// FIXME: This should use mod/ref information to see if we can hoist or
sink
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