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| author | Nick Lewycky <nicholas@mxc.ca> | 2011-09-06 21:42:18 +0000 |
|---|---|---|
| committer | Nick Lewycky <nicholas@mxc.ca> | 2011-09-06 21:42:18 +0000 |
| commit | c103a08a1115249548d6bb57a74a16de4f0864e3 (patch) | |
| tree | 015086e49c8ab2b9b9997fa0d132cb4aee987075 /lib/Analysis | |
| parent | 34c4485b7479a12b5ef1cb15d27e96277e8a499a (diff) | |
| download | external_llvm-c103a08a1115249548d6bb57a74a16de4f0864e3.zip external_llvm-c103a08a1115249548d6bb57a74a16de4f0864e3.tar.gz external_llvm-c103a08a1115249548d6bb57a74a16de4f0864e3.tar.bz2 | |
This transform only handles two-operand AddRec's. Prevent it from trying to
handle anything more complex. Fixes PR10383 again!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139186 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis')
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 36 |
1 files changed, 23 insertions, 13 deletions
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index b4c4da6..57c4265 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -1974,7 +1974,8 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops, // multiplied together. If so, we can fold them. for (unsigned OtherIdx = Idx+1; OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); - ++OtherIdx) + ++OtherIdx) { + bool Retry = false; if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) { // {A,+,B}<L> * {C,+,D}<L> --> {A*C,+,A*D + B*C + B*D,+,2*B*D}<L> // @@ -1985,7 +1986,7 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops, // Rearranging, X = x, Y = y+z, Z = 2z. // // x = A*C, y = (A*D + B*C), z = B*D. - // Therefore X = A*C, Y = (A*D + B*C) + B*D and Z = 2*B*D. + // Therefore X = A*C, Y = A*D + B*C + B*D and Z = 2*B*D. for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]); ++OtherIdx) if (const SCEVAddRecExpr *OtherAddRec = @@ -2002,19 +2003,28 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops, const SCEV *NewSecondOrderStep = getMulExpr(BD, getConstant(BD->getType(), 2)); - SmallVector<const SCEV *, 3> AddRecOps; - AddRecOps.push_back(NewStart); - AddRecOps.push_back(NewStep); - AddRecOps.push_back(NewSecondOrderStep); - const SCEV *NewAddRec = getAddRecExpr(AddRecOps, - AddRec->getLoop(), - SCEV::FlagAnyWrap); - if (Ops.size() == 2) return NewAddRec; - Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec); - Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; + // This can happen when AddRec or OtherAddRec have >3 operands. + // TODO: support these add-recs. + if (isLoopInvariant(NewStart, AddRecLoop) && + isLoopInvariant(NewStep, AddRecLoop) && + isLoopInvariant(NewSecondOrderStep, AddRecLoop)) { + SmallVector<const SCEV *, 3> AddRecOps; + AddRecOps.push_back(NewStart); + AddRecOps.push_back(NewStep); + AddRecOps.push_back(NewSecondOrderStep); + const SCEV *NewAddRec = getAddRecExpr(AddRecOps, + AddRec->getLoop(), + SCEV::FlagAnyWrap); + if (Ops.size() == 2) return NewAddRec; + Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec); + Ops.erase(Ops.begin() + OtherIdx); --OtherIdx; + Retry = true; + } } - return getMulExpr(Ops); + if (Retry) + return getMulExpr(Ops); } + } // Otherwise couldn't fold anything into this recurrence. Move onto the // next one. |