#define DEBUG_TYPE "dse"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/Function.h"
-#include "llvm/GlobalVariable.h"
-#include "llvm/Instructions.h"
-#include "llvm/IntrinsicInst.h"
-#include "llvm/Pass.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SetVector.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/Target/TargetData.h"
-#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
-#include "llvm/ADT/SetVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
using namespace llvm;
STATISTIC(NumFastStores, "Number of stores deleted");
/// hasMemoryWrite - Does this instruction write some memory? This only returns
/// true for things that we can analyze with other helpers below.
-static bool hasMemoryWrite(Instruction *I) {
+static bool hasMemoryWrite(Instruction *I, const TargetLibraryInfo *TLI) {
if (isa<StoreInst>(I))
return true;
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
return true;
}
}
+ if (CallSite CS = I) {
+ if (Function *F = CS.getCalledFunction()) {
+ if (TLI && TLI->has(LibFunc::strcpy) &&
+ F->getName() == TLI->getName(LibFunc::strcpy)) {
+ return true;
+ }
+ if (TLI && TLI->has(LibFunc::strncpy) &&
+ F->getName() == TLI->getName(LibFunc::strncpy)) {
+ return true;
+ }
+ if (TLI && TLI->has(LibFunc::strcat) &&
+ F->getName() == TLI->getName(LibFunc::strcat)) {
+ return true;
+ }
+ if (TLI && TLI->has(LibFunc::strncat) &&
+ F->getName() == TLI->getName(LibFunc::strncat)) {
+ return true;
+ }
+ }
+ }
return false;
}
// If we don't have target data around, an unknown size in Location means
// that we should use the size of the pointee type. This isn't valid for
// memset/memcpy, which writes more than an i8.
- if (Loc.Size == AliasAnalysis::UnknownSize && AA.getTargetData() == 0)
+ if (Loc.Size == AliasAnalysis::UnknownSize && AA.getDataLayout() == 0)
return AliasAnalysis::Location();
return Loc;
}
// If we don't have target data around, an unknown size in Location means
// that we should use the size of the pointee type. This isn't valid for
// init.trampoline, which writes more than an i8.
- if (AA.getTargetData() == 0) return AliasAnalysis::Location();
+ if (AA.getDataLayout() == 0) return AliasAnalysis::Location();
// FIXME: We don't know the size of the trampoline, so we can't really
// handle it here.
/// instruction if any.
static AliasAnalysis::Location
getLocForRead(Instruction *Inst, AliasAnalysis &AA) {
- assert(hasMemoryWrite(Inst) && "Unknown instruction case");
+ assert(hasMemoryWrite(Inst, AA.getTargetLibraryInfo()) &&
+ "Unknown instruction case");
// The only instructions that both read and write are the mem transfer
// instructions (memcpy/memmove).
if (StoreInst *SI = dyn_cast<StoreInst>(I))
return SI->isUnordered();
- IntrinsicInst *II = cast<IntrinsicInst>(I);
- switch (II->getIntrinsicID()) {
- default: llvm_unreachable("doesn't pass 'hasMemoryWrite' predicate");
- case Intrinsic::lifetime_end:
- // Never remove dead lifetime_end's, e.g. because it is followed by a
- // free.
- return false;
- case Intrinsic::init_trampoline:
- // Always safe to remove init_trampoline.
- return true;
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+ switch (II->getIntrinsicID()) {
+ default: llvm_unreachable("doesn't pass 'hasMemoryWrite' predicate");
+ case Intrinsic::lifetime_end:
+ // Never remove dead lifetime_end's, e.g. because it is followed by a
+ // free.
+ return false;
+ case Intrinsic::init_trampoline:
+ // Always safe to remove init_trampoline.
+ return true;
- case Intrinsic::memset:
- case Intrinsic::memmove:
- case Intrinsic::memcpy:
- // Don't remove volatile memory intrinsics.
- return !cast<MemIntrinsic>(II)->isVolatile();
+ case Intrinsic::memset:
+ case Intrinsic::memmove:
+ case Intrinsic::memcpy:
+ // Don't remove volatile memory intrinsics.
+ return !cast<MemIntrinsic>(II)->isVolatile();
+ }
}
+
+ if (CallSite CS = I)
+ return CS.getInstruction()->use_empty();
+
+ return false;
}
if (isa<StoreInst>(I))
return false;
- IntrinsicInst *II = cast<IntrinsicInst>(I);
- switch (II->getIntrinsicID()) {
- default: return false;
- case Intrinsic::memset:
- case Intrinsic::memcpy:
- // Do shorten memory intrinsics.
- return true;
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+ switch (II->getIntrinsicID()) {
+ default: return false;
+ case Intrinsic::memset:
+ case Intrinsic::memcpy:
+ // Do shorten memory intrinsics.
+ return true;
+ }
}
+
+ // Don't shorten libcalls calls for now.
+
+ return false;
}
/// getStoredPointerOperand - Return the pointer that is being written to.
if (MemIntrinsic *MI = dyn_cast<MemIntrinsic>(I))
return MI->getDest();
- IntrinsicInst *II = cast<IntrinsicInst>(I);
- switch (II->getIntrinsicID()) {
- default: llvm_unreachable("Unexpected intrinsic!");
- case Intrinsic::init_trampoline:
- return II->getArgOperand(0);
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
+ switch (II->getIntrinsicID()) {
+ default: llvm_unreachable("Unexpected intrinsic!");
+ case Intrinsic::init_trampoline:
+ return II->getArgOperand(0);
+ }
}
+
+ CallSite CS = I;
+ // All the supported functions so far happen to have dest as their first
+ // argument.
+ return CS.getArgument(0);
}
static uint64_t getPointerSize(const Value *V, AliasAnalysis &AA) {
uint64_t Size;
- if (getObjectSize(V, Size, AA.getTargetData(), AA.getTargetLibraryInfo()))
+ if (getObjectSize(V, Size, AA.getDataLayout(), AA.getTargetLibraryInfo()))
return Size;
return AliasAnalysis::UnknownSize;
}
// comparison.
if (Later.Size == AliasAnalysis::UnknownSize ||
Earlier.Size == AliasAnalysis::UnknownSize) {
- // If we have no TargetData information around, then the size of the store
+ // If we have no DataLayout information around, then the size of the store
// is inferrable from the pointee type. If they are the same type, then
// we know that the store is safe.
- if (AA.getTargetData() == 0 &&
+ if (AA.getDataLayout() == 0 &&
Later.Ptr->getType() == Earlier.Ptr->getType())
return OverwriteComplete;
// larger than the earlier one.
if (Later.Size == AliasAnalysis::UnknownSize ||
Earlier.Size == AliasAnalysis::UnknownSize ||
- AA.getTargetData() == 0)
+ AA.getDataLayout() == 0)
return OverwriteUnknown;
// Check to see if the later store is to the entire object (either a global,
// an alloca, or a byval argument). If so, then it clearly overwrites any
// other store to the same object.
- const TargetData &TD = *AA.getTargetData();
+ const DataLayout &TD = *AA.getDataLayout();
const Value *UO1 = GetUnderlyingObject(P1, &TD),
*UO2 = GetUnderlyingObject(P2, &TD);
}
// If we find something that writes memory, get its memory dependence.
- if (!hasMemoryWrite(Inst))
+ if (!hasMemoryWrite(Inst, TLI))
continue;
MemDepResult InstDep = MD->getDependency(Inst);
MemDepResult Dep = MD->getPointerDependencyFrom(Loc, false, InstPt, BB);
while (Dep.isDef() || Dep.isClobber()) {
Instruction *Dependency = Dep.getInst();
- if (!hasMemoryWrite(Dependency) || !isRemovable(Dependency))
+ if (!hasMemoryWrite(Dependency, TLI) || !isRemovable(Dependency))
break;
Value *DepPointer =
return MadeChange;
}
+namespace {
+ struct CouldRef {
+ typedef Value *argument_type;
+ const CallSite CS;
+ AliasAnalysis *AA;
+
+ bool operator()(Value *I) {
+ // See if the call site touches the value.
+ AliasAnalysis::ModRefResult A =
+ AA->getModRefInfo(CS, I, getPointerSize(I, *AA));
+
+ return A == AliasAnalysis::ModRef || A == AliasAnalysis::Ref;
+ }
+ };
+}
+
/// handleEndBlock - Remove dead stores to stack-allocated locations in the
/// function end block. Ex:
/// %A = alloca i32
--BBI;
// If we find a store, check to see if it points into a dead stack value.
- if (hasMemoryWrite(BBI) && isRemovable(BBI)) {
+ if (hasMemoryWrite(BBI, TLI) && isRemovable(BBI)) {
// See through pointer-to-pointer bitcasts
SmallVector<Value *, 4> Pointers;
GetUnderlyingObjects(getStoredPointerOperand(BBI), Pointers);
// If the call might load from any of our allocas, then any store above
// the call is live.
- SmallVector<Value*, 8> LiveAllocas;
- for (SmallSetVector<Value*, 16>::iterator I = DeadStackObjects.begin(),
- E = DeadStackObjects.end(); I != E; ++I) {
- // See if the call site touches it.
- AliasAnalysis::ModRefResult A =
- AA->getModRefInfo(CS, *I, getPointerSize(*I, *AA));
-
- if (A == AliasAnalysis::ModRef || A == AliasAnalysis::Ref)
- LiveAllocas.push_back(*I);
- }
+ CouldRef Pred = { CS, AA };
+ DeadStackObjects.remove_if(Pred);
// If all of the allocas were clobbered by the call then we're not going
// to find anything else to process.
- if (DeadStackObjects.size() == LiveAllocas.size())
+ if (DeadStackObjects.empty())
break;
- for (SmallVector<Value*, 8>::iterator I = LiveAllocas.begin(),
- E = LiveAllocas.end(); I != E; ++I)
- DeadStackObjects.remove(*I);
-
continue;
}
return MadeChange;
}
+namespace {
+ struct CouldAlias {
+ typedef Value *argument_type;
+ const AliasAnalysis::Location &LoadedLoc;
+ AliasAnalysis *AA;
+
+ bool operator()(Value *I) {
+ // See if the loaded location could alias the stack location.
+ AliasAnalysis::Location StackLoc(I, getPointerSize(I, *AA));
+ return !AA->isNoAlias(StackLoc, LoadedLoc);
+ }
+ };
+}
+
/// RemoveAccessedObjects - Check to see if the specified location may alias any
/// of the stack objects in the DeadStackObjects set. If so, they become live
/// because the location is being loaded.
return;
}
- SmallVector<Value*, 16> NowLive;
- for (SmallSetVector<Value*, 16>::iterator I = DeadStackObjects.begin(),
- E = DeadStackObjects.end(); I != E; ++I) {
- // See if the loaded location could alias the stack location.
- AliasAnalysis::Location StackLoc(*I, getPointerSize(*I, *AA));
- if (!AA->isNoAlias(StackLoc, LoadedLoc))
- NowLive.push_back(*I);
- }
-
- for (SmallVector<Value*, 16>::iterator I = NowLive.begin(), E = NowLive.end();
- I != E; ++I)
- DeadStackObjects.remove(*I);
+ // Remove objects that could alias LoadedLoc.
+ CouldAlias Pred = { LoadedLoc, AA };
+ DeadStackObjects.remove_if(Pred);
}