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Rearrange some code, no functionality changes.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17724 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-11-14 04:24:28 +00:00
parent 1c745818ff
commit f5990edc87
1 changed files with 68 additions and 49 deletions
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117
lib/Transforms/Scalar/ScalarReplAggregates.cpp
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@ -54,9 +54,10 @@ namespace {
}
private:
bool isSafeElementUse(Value *Ptr);
bool isSafeUseOfAllocation(Instruction *User);
bool isSafeAllocaToPromote(AllocationInst *AI);
int isSafeElementUse(Value *Ptr);
int isSafeUseOfAllocation(Instruction *User);
int isSafeAllocaToScalarRepl(AllocationInst *AI);
void CanonicalizeAllocaUsers(AllocationInst *AI);
AllocaInst *AddNewAlloca(Function &F, const Type *Ty, AllocationInst *Base);
};
@ -141,8 +142,15 @@ bool SROA::performScalarRepl(Function &F) {
// Check that all of the users of the allocation are capable of being
// transformed.
if (!isSafeAllocaToPromote(AI))
switch (isSafeAllocaToScalarRepl(AI)) {
default: assert(0 && "Unexpected value!");
case 0: // Not safe to scalar replace.
continue;
case 1: // Safe, but requires cleanup/canonicalizations first
CanonicalizeAllocaUsers(AI);
case 3: // Safe to scalar replace.
break;
}
DEBUG(std::cerr << "Found inst to xform: " << *AI);
Changed = true;
@ -217,11 +225,42 @@ bool SROA::performScalarRepl(Function &F) {
}
/// isSafeElementUse - Check to see if this use is an allowed use for a
/// getelementptr instruction of an array aggregate allocation.
///
int SROA::isSafeElementUse(Value *Ptr) {
for (Value::use_iterator I = Ptr->use_begin(), E = Ptr->use_end();
I != E; ++I) {
Instruction *User = cast<Instruction>(*I);
switch (User->getOpcode()) {
case Instruction::Load: break;
case Instruction::Store:
// Store is ok if storing INTO the pointer, not storing the pointer
if (User->getOperand(0) == Ptr) return 0;
break;
case Instruction::GetElementPtr: {
GetElementPtrInst *GEP = cast<GetElementPtrInst>(User);
if (GEP->getNumOperands() > 1) {
if (!isa<Constant>(GEP->getOperand(1)) ||
!cast<Constant>(GEP->getOperand(1))->isNullValue())
return 0; // Using pointer arithmetic to navigate the array...
}
if (!isSafeElementUse(GEP)) return 0;
break;
}
default:
DEBUG(std::cerr << " Transformation preventing inst: " << *User);
return 0;
}
}
return 3; // All users look ok :)
}
/// isSafeUseOfAllocation - Check to see if this user is an allowed use for an
/// aggregate allocation.
///
bool SROA::isSafeUseOfAllocation(Instruction *User) {
if (!isa<GetElementPtrInst>(User)) return false;
int SROA::isSafeUseOfAllocation(Instruction *User) {
if (!isa<GetElementPtrInst>(User)) return 0;
GetElementPtrInst *GEPI = cast<GetElementPtrInst>(User);
gep_type_iterator I = gep_type_begin(GEPI), E = gep_type_end(GEPI);
@ -229,11 +268,11 @@ bool SROA::isSafeUseOfAllocation(Instruction *User) {
// The GEP is safe to transform if it is of the form GEP <ptr>, 0, <cst>
if (I == E ||
I.getOperand() != Constant::getNullValue(I.getOperand()->getType()))
return false;
return 0;
++I;
if (I == E || !isa<ConstantInt>(I.getOperand()))
return false;
return 0;
// If this is a use of an array allocation, do a bit more checking for sanity.
if (const ArrayType *AT = dyn_cast<ArrayType>(*I)) {
@ -243,7 +282,7 @@ bool SROA::isSafeUseOfAllocation(Instruction *User) {
// something funny is going on, so we won't do the optimization.
//
if (cast<ConstantInt>(GEPI->getOperand(2))->getRawValue() >= NumElements)
return false;
return 0;
}
// If there are any non-simple uses of this getelementptr, make sure to reject
@ -251,51 +290,31 @@ bool SROA::isSafeUseOfAllocation(Instruction *User) {
return isSafeElementUse(GEPI);
}
/// isSafeElementUse - Check to see if this use is an allowed use for a
/// getelementptr instruction of an array aggregate allocation.
/// isSafeStructAllocaToScalarRepl - Check to see if the specified allocation of
/// an aggregate can be broken down into elements. Return 0 if not, 3 if safe,
/// or 1 if safe after canonicalization has been performed.
///
bool SROA::isSafeElementUse(Value *Ptr) {
for (Value::use_iterator I = Ptr->use_begin(), E = Ptr->use_end();
I != E; ++I) {
Instruction *User = cast<Instruction>(*I);
switch (User->getOpcode()) {
case Instruction::Load: break;
case Instruction::Store:
// Store is ok if storing INTO the pointer, not storing the pointer
if (User->getOperand(0) == Ptr) return false;
break;
case Instruction::GetElementPtr: {
GetElementPtrInst *GEP = cast<GetElementPtrInst>(User);
if (GEP->getNumOperands() > 1) {
if (!isa<Constant>(GEP->getOperand(1)) ||
!cast<Constant>(GEP->getOperand(1))->isNullValue())
return false; // Using pointer arithmetic to navigate the array...
}
if (!isSafeElementUse(GEP)) return false;
break;
}
default:
DEBUG(std::cerr << " Transformation preventing inst: " << *User);
return false;
}
}
return true; // All users look ok :)
}
/// isSafeStructAllocaToPromote - Check to see if the specified allocation of a
/// structure can be broken down into elements.
///
bool SROA::isSafeAllocaToPromote(AllocationInst *AI) {
int SROA::isSafeAllocaToScalarRepl(AllocationInst *AI) {
// Loop over the use list of the alloca. We can only transform it if all of
// the users are safe to transform.
//
int isSafe = 3;
for (Value::use_iterator I = AI->use_begin(), E = AI->use_end();
I != E; ++I)
if (!isSafeUseOfAllocation(cast<Instruction>(*I))) {
I != E; ++I) {
isSafe &= isSafeUseOfAllocation(cast<Instruction>(*I));
if (isSafe == 0) {
DEBUG(std::cerr << "Cannot transform: " << *AI << " due to user: "
<< **I);
return false;
<< **I);
return 0;
}
return true;
}
// If we require cleanup, isSafe is now 1, otherwise it is 3.
return isSafe;
}
/// CanonicalizeAllocaUsers - If SROA reported that it can promote the specified
/// allocation, but only if cleaned up, perform the cleanups required.
void SROA::CanonicalizeAllocaUsers(AllocationInst *AI) {
}