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A few minor micro-optimizations.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106764 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-06-24 16:57:52 +00:00
parent d42819a07b
commit 2ea09e0546
1 changed files with 11 additions and 5 deletions
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16
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@ -449,6 +449,7 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
if (!Step) return 0;
return SE.getAddRecExpr(Start, Step, AR->getLoop());
}
return 0;
}
// Distribute the sdiv over add operands, if the add doesn't overflow.
@ -464,10 +465,11 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
}
return SE.getAddExpr(Ops);
}
return 0;
}
// Check for a multiply operand that we can pull RHS out of.
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS))
if (const SCEVMulExpr *Mul = dyn_cast<SCEVMulExpr>(LHS)) {
if (IgnoreSignificantBits || isMulSExtable(Mul, SE)) {
SmallVector<const SCEV *, 4> Ops;
bool Found = false;
@ -484,6 +486,8 @@ static const SCEV *getExactSDiv(const SCEV *LHS, const SCEV *RHS,
}
return Found ? SE.getMulExpr(Ops) : 0;
}
return 0;
}
// Otherwise we don't know.
return 0;
@ -2397,13 +2401,12 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
for (SmallSetVector<int64_t, 8>::const_iterator
I = Factors.begin(), E = Factors.end(); I != E; ++I) {
int64_t Factor = *I;
Formula F = Base;
// Check that the multiplication doesn't overflow.
if (F.AM.BaseOffs == INT64_MIN && Factor == -1)
if (Base.AM.BaseOffs == INT64_MIN && Factor == -1)
continue;
F.AM.BaseOffs = (uint64_t)Base.AM.BaseOffs * Factor;
if (F.AM.BaseOffs / Factor != Base.AM.BaseOffs)
int64_t NewBaseOffs = (uint64_t)Base.AM.BaseOffs * Factor;
if (NewBaseOffs / Factor != Base.AM.BaseOffs)
continue;
// Check that multiplying with the use offset doesn't overflow.
@ -2414,6 +2417,9 @@ void LSRInstance::GenerateICmpZeroScales(LSRUse &LU, unsigned LUIdx,
if (Offset / Factor != LU.MinOffset)
continue;
Formula F = Base;
F.AM.BaseOffs = NewBaseOffs;
// Check that this scale is legal.
if (!isLegalUse(F.AM, Offset, Offset, LU.Kind, LU.AccessTy, TLI))
continue;