This patch introduces `SCEVDivisionPrinterPass` and registers it under
the name `print<scev-division>`, primarily for testing purposes. This
pass invokes `SCEVDivision::divide` upon encountering `sdiv`, and prints
the numerator, denominator, quotient, and remainder. It also adds
several test cases, some of which are currently incorrect and require
fixing.
Along with that, this patch added some comments to clarify the behavior
of `SCEVDivision::divide`, as follows:
- This function does NOT actually perform the division
- Given the `Numerator` and `Denominator`, find a pair
`(Quotient, Remainder)` s.t.
`Numerator = Quotient * Denominator + Remainder`
- The common condition `Remainder < Denominator` is NOT necessarily
required
- There may be multiple solutions for `(Quotient, Remainder)`, and this
function finds one of them
- Especially, there is always a trivial solution `(0, Numerator)`
- The following computations may wrap
- The multiplication of `Quotient` and `Denominator`
- The addition of `Quotient * Denominator` and `Remainder`
Related discussion: #154745
Namespaces are terminated with a closing comment in the majority of the
codebase so do the same here for consistency. Also format code within
some namespaces to make clang-format happy.
This is part of an effort to remove ConstantExpr based
representations of `vscale` so that its LangRef definiton can
be relaxed to accommodate a less strict definition of constant.
Differential Revision: https://reviews.llvm.org/D144891
This patch extends SCEVParameterRewriter to support rewriting unknown
epxressions to arbitrary SCEV expressions. It will be used by further
patches.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D67176
This makes it usable from outside of SCEV,
while previously it was internal to the ScalarEvolution.cpp
In particular, i want to use it in an WIP alloca promotion helper pass,
to analyze if some SCEV is a multiple of some other SCEV.
