[llvm] r275357 - [SCCP] Generalize tryToReplaceInstWithConstant to work also with arguments.
Matthew Simpson via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 18 17:04:00 PDT 2016
r275468 fixed it for us. Thanks, Davide!
-- Matt
On Monday, July 18, 2016, Davide Italiano via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Are you still seeing problems?
>
> On Thu, Jul 14, 2016 at 1:34 PM, Davide Italiano <davide at freebsd.org
> <javascript:;>> wrote:
> > On Thu, Jul 14, 2016 at 12:27 PM, Matthew Simpson
> > <mssimpso at codeaurora.org <javascript:;>> wrote:
> >> Hi Davide,
> >>
> >> We're seeing large compile-time regressions with this change and LTO
> when
> >> compiling spec2000/2006. For example, the compile-time of
> spec2000/crafty
> >> roughly doubles. Would you mind taking a look? We're compiling with
> "-Ofast
> >> -flto -fuse-ld=gold -mcpu=kryo". Please let me know if you're unable to
> >> reproduce. Thanks!
> >>
> >
> > Sorry about that, r275468 should help, please let me know if you still
> > have trouble!
> >
> >> -- Matt
> >>
> >>
> >>
> >> On Wed, Jul 13, 2016 at 10:34 PM, Davide Italiano via llvm-commits
> >> <llvm-commits at lists.llvm.org <javascript:;>> wrote:
> >>>
> >>> On Wed, Jul 13, 2016 at 6:51 PM, Eli Friedman <eli.friedman at gmail.com
> <javascript:;>>
> >>> wrote:
> >>> > On Wed, Jul 13, 2016 at 6:27 PM, Davide Italiano via llvm-commits
> >>> > <llvm-commits at lists.llvm.org <javascript:;>> wrote:
> >>> >>
> >>> >> Author: davide
> >>> >> Date: Wed Jul 13 20:27:29 2016
> >>> >> New Revision: 275357
> >>> >>
> >>> >> URL: http://llvm.org/viewvc/llvm-project?rev=275357&view=rev
> >>> >> Log:
> >>> >> [SCCP] Generalize tryToReplaceInstWithConstant to work also with
> >>> >> arguments.
> >>> >>
> >>> >> Modified:
> >>> >> llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
> >>> >>
> >>> >> Modified: llvm/trunk/lib/Transforms/Scalar/SCCP.cpp
> >>> >> URL:
> >>> >>
> >>> >>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SCCP.cpp?rev=275357&r1=275356&r2=275357&view=diff
> >>> >>
> >>> >>
> >>> >>
> ==============================================================================
> >>> >> --- llvm/trunk/lib/Transforms/Scalar/SCCP.cpp (original)
> >>> >> +++ llvm/trunk/lib/Transforms/Scalar/SCCP.cpp Wed Jul 13 20:27:29
> 2016
> >>> >> @@ -1510,16 +1510,16 @@ bool SCCPSolver::ResolvedUndefsIn(Functi
> >>> >> return false;
> >>> >> }
> >>> >>
> >>> >> -static bool tryToReplaceInstWithConstant(SCCPSolver Solver,
> >>> >> Instruction
> >>> >> *Inst,
> >>> >> - bool
> shouldEraseFromParent) {
> >>> >> +template <typename ArgOrInst>
> >>> >> +static bool tryToReplaceWithConstant(SCCPSolver Solver, ArgOrInst
> *AI)
> >>> >> {
> >>> >
> >>> >
> >>> > Can you just use a Value* here?
> >>> >
> >>>
> >>> Sure, I'll change that.
> >>>
> >>> >>
> >>> >> Constant *Const = nullptr;
> >>> >> - if (Inst->getType()->isStructTy()) {
> >>> >> - std::vector<LatticeVal> IVs =
> >>> >> Solver.getStructLatticeValueFor(Inst);
> >>> >> + if (AI->getType()->isStructTy()) {
> >>> >> + std::vector<LatticeVal> IVs =
> Solver.getStructLatticeValueFor(AI);
> >>> >> if (std::any_of(IVs.begin(), IVs.end(),
> >>> >> [](LatticeVal &LV) { return LV.isOverdefined();
> >>> >> }))
> >>> >> return false;
> >>> >> std::vector<Constant *> ConstVals;
> >>> >> - StructType *ST = dyn_cast<StructType>(Inst->getType());
> >>> >> + StructType *ST = dyn_cast<StructType>(AI->getType());
> >>> >> for (unsigned i = 0, e = ST->getNumElements(); i != e; ++i) {
> >>> >> LatticeVal V = IVs[i];
> >>> >> ConstVals.push_back(V.isConstant()
> >>> >> @@ -1528,18 +1528,23 @@ static bool tryToReplaceInstWithConstant
> >>> >> }
> >>> >> Const = ConstantStruct::get(ST, ConstVals);
> >>> >> } else {
> >>> >> - LatticeVal IV = Solver.getLatticeValueFor(Inst);
> >>> >> + LatticeVal IV = Solver.getLatticeValueFor(AI);
> >>> >> if (IV.isOverdefined())
> >>> >> return false;
> >>> >> -
> >>> >> - Const =
> >>> >> - IV.isConstant() ? IV.getConstant() :
> >>> >> UndefValue::get(Inst->getType());
> >>> >> + Const = IV.isConstant() ? IV.getConstant() :
> >>> >> UndefValue::get(AI->getType());
> >>> >> }
> >>> >> assert(Const && "Constant is nullptr here!");
> >>> >> - DEBUG(dbgs() << " Constant: " << *Const << " = " << *Inst <<
> '\n');
> >>> >> + DEBUG(dbgs() << " Constant: " << *Const << " = " << *AI <<
> '\n');
> >>> >>
> >>> >> // Replaces all of the uses of a variable with uses of the
> constant.
> >>> >> - Inst->replaceAllUsesWith(Const);
> >>> >> + AI->replaceAllUsesWith(Const);
> >>> >> + return true;
> >>> >> +}
> >>> >> +
> >>> >> +static bool tryToReplaceInstWithConstant(SCCPSolver Solver,
> >>> >> Instruction
> >>> >> *Inst,
> >>> >> + bool
> shouldEraseFromParent) {
> >>> >> + if (!tryToReplaceWithConstant(Solver, Inst))
> >>> >> + return false;
> >>> >>
> >>> >> // Delete the instruction.
> >>> >> if (shouldEraseFromParent)
> >>> >> @@ -1766,17 +1771,8 @@ static bool runIPSCCP(Module &M, const D
> >>> >> // TODO: Could use getStructLatticeValueFor to find out if
> the
> >>> >> entire
> >>> >> // result is a constant and replace it entirely if so.
> >>> >>
> >>> >> - LatticeVal IV = Solver.getLatticeValueFor(&*AI);
> >>> >> - if (IV.isOverdefined()) continue;
> >>> >> -
> >>> >> - Constant *CST = IV.isConstant() ?
> >>> >> - IV.getConstant() : UndefValue::get(AI->getType());
> >>> >> - DEBUG(dbgs() << "*** Arg " << *AI << " = " << *CST
> <<"\n");
> >>> >> -
> >>> >> - // Replaces all of the uses of a variable with uses of the
> >>> >> - // constant.
> >>> >> - AI->replaceAllUsesWith(CST);
> >>> >> - ++IPNumArgsElimed;
> >>> >> + if (tryToReplaceWithConstant(Solver, &*AI))
> >>> >> + ++IPNumArgsElimed;
> >>> >> }
> >>> >> }
> >>> >
> >>> >
> >>> > Testcase?
> >>> >
> >>>
> >>> Sorry if I failed to mention on this commit, but this is NFC as we
> >>> skip the replacement phase if the argument is of struct type (unless
> >>> I'm missing something).
> >>> My next patch, http://reviews.llvm.org/D22329 , changes the behaviour
> >>> and add test cases.
> >>>
> >>>
> >>> Thanks for your review!
> >>>
> >>> --
> >>> Davide
> >>>
> >>> "There are no solved problems; there are only problems that are more
> >>> or less solved" -- Henri Poincare
> >>> _______________________________________________
> >>> llvm-commits mailing list
> >>> llvm-commits at lists.llvm.org <javascript:;>
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
> >>
> >>
> >
> >
> >
> > --
> > Davide
> >
> > "There are no solved problems; there are only problems that are more
> > or less solved" -- Henri Poincare
>
>
>
> --
> Davide
>
> "There are no solved problems; there are only problems that are more
> or less solved" -- Henri Poincare
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org <javascript:;>
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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