6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-17 03:30:28 +00:00
Code Issues Projects Releases Wiki Activity

LSR cost metric minor fix and verification.

Browse Source 
The minor bug heuristic was noticed by inspection. I added the
isLoser/isValid helpers because they will become more
important with subsequent checkins.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140580 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Trick 2011-09-26 23:11:04 +00:00
parent 21733e8f80
commit 7d11bd850f
1 changed files with 26 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
lib/Transforms/Scalar/LoopStrengthReduce.cpp
View File

@ -670,6 +670,21 @@ public:
void Loose();
#ifndef NDEBUG
// Once any of the metrics loses, they must all remain losers.
bool isValid() {
return ((NumRegs | AddRecCost | NumIVMuls | NumBaseAdds
| ImmCost | SetupCost) != ~0u)
|| ((NumRegs & AddRecCost & NumIVMuls & NumBaseAdds
& ImmCost & SetupCost) == ~0u);
}
#endif
bool isLoser() {
assert(isValid() && "invalid cost");
return NumRegs == ~0u;
}
void RateFormula(const Formula &F,
SmallPtrSet<const SCEV *, 16> &Regs,
const DenseSet<const SCEV *> &VisitedRegs,
@ -710,19 +725,22 @@ void Cost::RateRegister(const SCEV *Reg,
(!AR->getLoop()->contains(L) &&
DT.dominates(L->getHeader(), AR->getLoop()->getHeader()))) {
for (BasicBlock::iterator I = AR->getLoop()->getHeader()->begin();
PHINode *PN = dyn_cast<PHINode>(I); ++I)
PHINode *PN = dyn_cast<PHINode>(I); ++I) {
if (SE.isSCEVable(PN->getType()) &&
(SE.getEffectiveSCEVType(PN->getType()) ==
SE.getEffectiveSCEVType(AR->getType())) &&
SE.getSCEV(PN) == AR)
return;
}
// If this isn't one of the addrecs that the loop already has, it
// would require a costly new phi and add. TODO: This isn't
// precisely modeled right now.
++NumBaseAdds;
if (!Regs.count(AR->getStart()))
if (!Regs.count(AR->getStart())) {
RateRegister(AR->getStart(), Regs, L, SE, DT);
if (isLoser())
return;
}
}
// Add the step value register, if it needs one.
@ -769,6 +787,8 @@ void Cost::RateFormula(const Formula &F,
return;
}
RatePrimaryRegister(ScaledReg, Regs, L, SE, DT);
if (isLoser())
return;
}
for (SmallVectorImpl<const SCEV *>::const_iterator I = F.BaseRegs.begin(),
E = F.BaseRegs.end(); I != E; ++I) {
@ -778,6 +798,8 @@ void Cost::RateFormula(const Formula &F,
return;
}
RatePrimaryRegister(BaseReg, Regs, L, SE, DT);
if (isLoser())
return;
}
// Determine how many (unfolded) adds we'll need inside the loop.
@ -795,6 +817,7 @@ void Cost::RateFormula(const Formula &F,
else if (Offset != 0)
ImmCost += APInt(64, Offset, true).getMinSignedBits();
}
assert(isValid() && "invalid cost");
}
/// Loose - Set this cost to a losing value.