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use types of loads and stores, not address, in CheckForIVReuse

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35197 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dale Johannesen 2007-03-20 00:47:50 +00:00
parent 80dae195c7
commit dc42f48ea9
1 changed files with 28 additions and 7 deletions
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35
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -43,6 +43,9 @@ STATISTIC(NumInserted, "Number of PHIs inserted");
STATISTIC(NumVariable, "Number of PHIs with variable strides");
namespace {
class BasedUser;
/// IVStrideUse - Keep track of one use of a strided induction variable, where
/// the stride is stored externally. The Offset member keeps track of the
/// offset from the IV, User is the actual user of the operand, and 'Operand'
@ -174,7 +177,10 @@ private:
void OptimizeIndvars(Loop *L);
unsigned CheckForIVReuse(const SCEVHandle&, IVExpr&, const Type*);
unsigned CheckForIVReuse(const SCEVHandle&, IVExpr&, const Type*,
const std::vector<BasedUser>& UsersToProcess);
bool ValidStride(int64_t, const std::vector<BasedUser>& UsersToProcess);
void StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
IVUsersOfOneStride &Uses,
@ -871,13 +877,25 @@ static bool isZero(SCEVHandle &V) {
return false;
}
/// ValidStride - Check whether the given Scale is valid for all loads and
/// stores in UsersToProcess. Pulled into a function to avoid disturbing the
/// sensibilities of those who dislike goto's.
///
bool LoopStrengthReduce::ValidStride(int64_t Scale,
const std::vector<BasedUser>& UsersToProcess) {
for (unsigned i=0, e = UsersToProcess.size(); i!=e; ++i)
if (!TLI->isLegalAddressScale(Scale, UsersToProcess[i].Inst->getType()))
return false;
return true;
}
/// CheckForIVReuse - Returns the multiple if the stride is the multiple
/// of a previous stride and it is a legal value for the target addressing
/// mode scale component. This allows the users of this stride to be rewritten
/// as prev iv * factor. It returns 0 if no reuse is possible.
unsigned LoopStrengthReduce::CheckForIVReuse(const SCEVHandle &Stride,
IVExpr &IV, const Type *Ty) {
unsigned LoopStrengthReduce::CheckForIVReuse(const SCEVHandle &Stride,
IVExpr &IV, const Type *Ty,
const std::vector<BasedUser>& UsersToProcess) {
if (!TLI) return 0;
if (SCEVConstant *SC = dyn_cast<SCEVConstant>(Stride)) {
@ -890,7 +908,11 @@ unsigned LoopStrengthReduce::CheckForIVReuse(const SCEVHandle &Stride,
if (unsigned(abs(SInt)) < SSInt || (SInt % SSInt) != 0)
continue;
int64_t Scale = SInt / SSInt;
if (TLI->isLegalAddressScale(Scale, Ty)) {
// Check that this stride is valid for all the types used for loads and
// stores; if it can be used for some and not others, we might as well use
// the original stride everywhere, since we have to create the IV for it
// anyway.
if (ValidStride(Scale, UsersToProcess))
for (std::vector<IVExpr>::iterator II = SI->second.IVs.begin(),
IE = SI->second.IVs.end(); II != IE; ++II)
// FIXME: Only handle base == 0 for now.
@ -899,10 +921,8 @@ unsigned LoopStrengthReduce::CheckForIVReuse(const SCEVHandle &Stride,
IV = *II;
return Scale;
}
}
}
}
return 0;
}
@ -955,7 +975,8 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride,
Value *IncV = NULL;
IVExpr ReuseIV;
unsigned RewriteFactor = CheckForIVReuse(Stride, ReuseIV,
CommonExprs->getType());
CommonExprs->getType(),
UsersToProcess);
if (RewriteFactor != 0) {
DOUT << "BASED ON IV of STRIDE " << *ReuseIV.Stride
<< " and BASE " << *ReuseIV.Base << " :\n";