Commit Graph

3 Commits

Author SHA1 Message Date
Roman Lebedev f1286621eb [InstSimplify] simplifyUnsignedRangeCheck(): handle more cases (PR43251)
Summary:
I don't have a direct motivational case for this,
but it would be good to have this for completeness/symmetry.

This pattern is basically the motivational pattern from
https://bugs.llvm.org/show_bug.cgi?id=43251
but with different predicate that requires that the offset is non-zero.

The completeness bit comes from the fact that a similar pattern (offset != zero)
will be needed for https://bugs.llvm.org/show_bug.cgi?id=43259,
so it'd seem to be good to not overlook very similar patterns..

Proofs: https://rise4fun.com/Alive/21b

Also, there is something odd with `isKnownNonZero()`, if the non-zero
knowledge was specified as an assumption, it didn't pick it up (PR43267)

Reviewers: spatel, nikic, xbolva00

Reviewed By: spatel

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67411

llvm-svn: 371718
2019-09-12 09:26:17 +00:00
Roman Lebedev 870ffe3cee [NFC][InstSimplify] rewrite test added in r371537 to use non-null pointer instead
I only want to ensure that %offset is non-zero there,
it doesn't matter how that info is conveyed.
As filed in PR43267, the assumption way does not work.

llvm-svn: 371546
2019-09-10 18:40:00 +00:00
Roman Lebedev 880657c97c [NFC][InstCombine][InstSimplify] PR43251 - and some patterns with offset != 0
https://rise4fun.com/Alive/21b

llvm-svn: 371537
2019-09-10 17:13:59 +00:00