This patch aims to improve compile time performance by increasing

the SCEV vector size in LoopStrengthReduce. It is observed that
the BaseRegs vector size is 4 in most cases,
and elements are frequently copied when it is initialized as
SmallVector<const SCEV *, 2> BaseRegs.
Our benchmark results show that the compilation time performance
improved by ~0.5%.

Patch by Wan Xiaofei.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174219 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Preston Gurd 2013-02-01 20:41:27 +00:00
parent 03fce7074e
commit 83474ee594

View File

@ -237,7 +237,7 @@ struct Formula {
/// BaseRegs - The list of "base" registers for this use. When this is
/// non-empty,
SmallVector<const SCEV *, 2> BaseRegs;
SmallVector<const SCEV *, 4> BaseRegs;
/// ScaledReg - The 'scaled' register for this use. This should be non-null
/// when Scale is not zero.
@ -1087,19 +1087,19 @@ namespace {
/// UniquifierDenseMapInfo - A DenseMapInfo implementation for holding
/// DenseMaps and DenseSets of sorted SmallVectors of const SCEV*.
struct UniquifierDenseMapInfo {
static SmallVector<const SCEV *, 2> getEmptyKey() {
SmallVector<const SCEV *, 2> V;
static SmallVector<const SCEV *, 4> getEmptyKey() {
SmallVector<const SCEV *, 4> V;
V.push_back(reinterpret_cast<const SCEV *>(-1));
return V;
}
static SmallVector<const SCEV *, 2> getTombstoneKey() {
SmallVector<const SCEV *, 2> V;
static SmallVector<const SCEV *, 4> getTombstoneKey() {
SmallVector<const SCEV *, 4> V;
V.push_back(reinterpret_cast<const SCEV *>(-2));
return V;
}
static unsigned getHashValue(const SmallVector<const SCEV *, 2> &V) {
static unsigned getHashValue(const SmallVector<const SCEV *, 4> &V) {
unsigned Result = 0;
for (SmallVectorImpl<const SCEV *>::const_iterator I = V.begin(),
E = V.end(); I != E; ++I)
@ -1107,8 +1107,8 @@ struct UniquifierDenseMapInfo {
return Result;
}
static bool isEqual(const SmallVector<const SCEV *, 2> &LHS,
const SmallVector<const SCEV *, 2> &RHS) {
static bool isEqual(const SmallVector<const SCEV *, 4> &LHS,
const SmallVector<const SCEV *, 4> &RHS) {
return LHS == RHS;
}
};
@ -1119,7 +1119,7 @@ struct UniquifierDenseMapInfo {
/// the user itself, and information about how the use may be satisfied.
/// TODO: Represent multiple users of the same expression in common?
class LSRUse {
DenseSet<SmallVector<const SCEV *, 2>, UniquifierDenseMapInfo> Uniquifier;
DenseSet<SmallVector<const SCEV *, 4>, UniquifierDenseMapInfo> Uniquifier;
public:
/// KindType - An enum for a kind of use, indicating what types of
@ -1178,7 +1178,7 @@ public:
/// HasFormula - Test whether this use as a formula which has the same
/// registers as the given formula.
bool LSRUse::HasFormulaWithSameRegs(const Formula &F) const {
SmallVector<const SCEV *, 2> Key = F.BaseRegs;
SmallVector<const SCEV *, 4> Key = F.BaseRegs;
if (F.ScaledReg) Key.push_back(F.ScaledReg);
// Unstable sort by host order ok, because this is only used for uniquifying.
std::sort(Key.begin(), Key.end());
@ -1188,7 +1188,7 @@ bool LSRUse::HasFormulaWithSameRegs(const Formula &F) const {
/// InsertFormula - If the given formula has not yet been inserted, add it to
/// the list, and return true. Return false otherwise.
bool LSRUse::InsertFormula(const Formula &F) {
SmallVector<const SCEV *, 2> Key = F.BaseRegs;
SmallVector<const SCEV *, 4> Key = F.BaseRegs;
if (F.ScaledReg) Key.push_back(F.ScaledReg);
// Unstable sort by host order ok, because this is only used for uniquifying.
std::sort(Key.begin(), Key.end());
@ -3656,7 +3656,7 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
// Collect the best formula for each unique set of shared registers. This
// is reset for each use.
typedef DenseMap<SmallVector<const SCEV *, 2>, size_t, UniquifierDenseMapInfo>
typedef DenseMap<SmallVector<const SCEV *, 4>, size_t, UniquifierDenseMapInfo>
BestFormulaeTy;
BestFormulaeTy BestFormulae;
@ -3691,7 +3691,7 @@ void LSRInstance::FilterOutUndesirableDedicatedRegisters() {
dbgs() << "\n");
}
else {
SmallVector<const SCEV *, 2> Key;
SmallVector<const SCEV *, 4> Key;
for (SmallVectorImpl<const SCEV *>::const_iterator J = F.BaseRegs.begin(),
JE = F.BaseRegs.end(); J != JE; ++J) {
const SCEV *Reg = *J;