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...re guaranteed to have no overflow. // // No self-wrap cannot be guaranteed after changing the step size, but // will be inferred if either NUW or NSW is true. Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); // If all of the other operands were loop invariant, we are done. if (Ops.size() == 1) return NewRec; I understand that you can't assume it won't wrap around with the new stride, but I couldn't find anything else later that would re-assign NSW/NUW. Maybe I need to...

...overflow. > // > // No self-wrap cannot be guaranteed after changing the step size, but > // will be inferred if either NUW or NSW is true. > Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); > const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); > > // If all of the other operands were loop invariant, we are done. > if (Ops.size() == 1) return NewRec; > > I understand that you can't assume it won't wrap around with the new stride, but I couldn't find anything else later that would re-assign...

On 16 November 2013 06:56, Andrew Trick <atrick at apple.com> wrote: > - getMulExpr constructs a new AddRec with NSW: > > Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); > const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); > Hi Andrew, Thanks for looking at this. Clearing the flags here makes sense, but it's being too conservative. I'm thinking I'll need something like propagateSafeFlags(...) with knowledge of the loop induction ranges or something else instead of simply relying on later pr...

...pagate the NUW and NSW flags if both the > // outer add and the inner addrec are guaranteed to have no > overflow. > // Always propagate NW. > Flags = AddRec->getNoWrapFlags(setFlags(Flags, SCEV::FlagNW)); > const SCEV *NewRec = getAddRecExpr(AddRecOps, AddRecLoop, Flags); > > // If all of the other operands were loop invariant, we are done. > if (Ops.size() == 1) return NewRec; > > Thanks! > -- Sanjoy > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-...

​Hi, Would you be able to kindly check and assist with the IndVarSimplify / SCEV problem I got in the latest LLVM, please? Sometimes IndVarSimplify may not eliminate narrow IV's when there actually exists such a possibility. This may affect other LLVM passes and result in inefficient code. The reproducing test 'indvar_test.cpp' is attached. The problem is with the second

...e: > >> On 16 November 2013 06:56, Andrew Trick <atrick at apple.com> wrote: >> - getMulExpr constructs a new AddRec with NSW: >> >> Flags = AddRec->getNoWrapFlags(clearFlags(Flags, SCEV::FlagNW)); >> const SCEV *NewRec = getAddRecExpr(NewOps, AddRecLoop, Flags); > > Hi Andrew, > > Thanks for looking at this. > > Clearing the flags here makes sense, but it's being too conservative. I'm thinking I'll need something like propagateSafeFlags(...) with knowledge of the loop induction ranges or something else instead of s...