We would eventually catch these via demanded bits and computing known bits in InstCombine,
but I think it's better to handle the simple cases as soon as possible as a matter of efficiency.
This fold allows further simplifications based on distributed ops transforms. eg:
%a = lshr i8 %x, 7
%b = or i8 %a, 2
%c = and i8 %b, 1
InstSimplify can directly fold this now:
%a = lshr i8 %x, 7
Differential Revision: https://reviews.llvm.org/D33221
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@303213 91177308-0d34-0410-b5e6-96231b3b80d8
Surprisingly, I don't think these are redundant for InstSimplify.
They were just misplaced as InstCombine tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302684 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Re-applying r301766 with a fix to a typo and a regression test.
The log message for r301766 was:
==================================================================================
InstructionSimplify: Canonicalize shuffle operands. NFC-ish.
Summary:
Apply canonicalization rules:
1. Input vectors with no elements selected from can be replaced with undef.
2. If only one input vector is constant it shall be the second one.
This allows constant-folding to cover more ad-hoc simplifications that
were in place and avoid duplication for RHS and LHS checks.
There are more rules we may want to add in the future when we see a
justification. e.g. mask elements that select undef elements can be
replaced with undef.
==================================================================================
Reviewers: spatel, RKSimon
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32863
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302373 91177308-0d34-0410-b5e6-96231b3b80d8
We can simplify (or (icmp X, C1), (icmp X, C2)) to 'true' or one of the icmps in many cases.
I had to check some of these with Alive to prove to myself it's right, but everything seems
to check out. Eg, the deleted code in instcombine was completely ignoring predicates with
mismatched signedness.
This is a follow-up to:
https://reviews.llvm.org/rL301260https://reviews.llvm.org/D32143
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302370 91177308-0d34-0410-b5e6-96231b3b80d8
The sibling folds for 'and' with casts were added with https://reviews.llvm.org/rL273200.
This is a preliminary step for adding the 'or' variants for the folds added with https://reviews.llvm.org/rL301260.
The reason for the strange form with constant LHS in the 1st test is because there's another missing fold in that
case for the inverted predicate. That should be fixed when we add the ConstantRange functionality for 'or-of-icmps'
that already exists for 'and-of-icmps'.
I'm hoping to share more code for the and/or cases, so we won't have these differences. This will allow us to remove
code from InstCombine. It's also possible that we can remove some code here in InstSimplify. I think we have some
duplicated folds because patterns are not matched in a general way.
Differential Revision: https://reviews.llvm.org/D32876
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302189 91177308-0d34-0410-b5e6-96231b3b80d8
This change caused buildbot failures, apparently because we're not
passing around types that InstSimplify is used to seeing. I'm not overly
familiar with InstSimplify, so I'm reverting this until I can figure out
what exactly is wrong.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301885 91177308-0d34-0410-b5e6-96231b3b80d8
The code Sanjay Patel moved over from InstCombine doesn't work properly if the 'and' has both inputs as nots because we used a commuted op matcher on the 'and' first. But this will bind to the first 'not' on 'and' when there could be two 'not's. InstCombine could rely on DeMorgan to ensure the 'and' wouldn't have two 'not's eventually, but InstSimplify can't rely on that.
This patch matches the xor first then checks for the ands and allows a not of either operand of the xor.
Differential Revision: https://reviews.llvm.org/D32458
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301329 91177308-0d34-0410-b5e6-96231b3b80d8
We can simplify (and (icmp X, C1), (icmp X, C2)) to one of the icmps in many cases.
I had to check some of these with Alive to prove to myself it's right, but everything
seems to check out. Eg, the code in instcombine was completely ignoring predicates with
mismatched signedness.
Handling or-of-icmps would be a follow-up step.
Differential Revision: https://reviews.llvm.org/D32143
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301260 91177308-0d34-0410-b5e6-96231b3b80d8
This is a straight cut and paste, but there's a bigger problem: if this
fold exists for simplifyOr, there should be a DeMorganized version for
simplifyAnd. But more than that, we have a patchwork of ad hoc logic
optimizations in InstCombine. There should be some structure to ensure
that we're not missing sibling folds across and/or/xor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301213 91177308-0d34-0410-b5e6-96231b3b80d8
This patch simplifies the examples from D31509 and D31927 (PR30630) and catches
the basic identity shuffle tests that Zvi recently added.
I'm not sure if we have something like this in DAGCombiner, but we should?
It's worth noting that "MaxRecurse / RecursionLimit" is only 3 on entry at the moment.
We might want to bump that up if there are longer shuffle chains like this in the wild.
For now, we're ignoring shuffles that have undef mask elements because it's not
clear how those should be handled.
Differential Revision: https://reviews.llvm.org/D31960
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300714 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Add a hook for simplification of shufflevector's with the following rules:
- Constant folding - NFC, as it was already being done by the default handler.
- If only one of the operands is constant, constant fold the shuffle if the
mask does not select elements from the variable operand - to show the hook is firing and affecting the test-cases.
Reviewers: RKSimon, craig.topper, spatel, sanjoy, nlopes, majnemer
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31525
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299393 91177308-0d34-0410-b5e6-96231b3b80d8
Adding some test-cases demonstrating cases that need to be improved.
To be followed by patches that improve these cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299189 91177308-0d34-0410-b5e6-96231b3b80d8
