Add tests to verifying future support for splat vectors containing poison/undef in llvm::decomposeBitTestICmp.
Differential Revision: https://reviews.llvm.org/D143031
This is NFC-intended for scalar code. There are still unnecessary
m_ConstantInt restrictions in surrounding code, so this is not a
complete fix.
This prevents regressions seen with a planned follow-on to D111410.
There's a substantial pile of scalar tests for transforms that
depend on this code, but zero vector coverage. This patch adds
a vector test next to the first scalar test in each file that
is affected by foldLogOpOfMaskedICmps.
The code that handles these transforms is artificially limited
from working with vector splat constants.
This replicates existing and/or tests to also test variants using
select. This should help us get a more accurate view on which
optimizations we're missing if we disable the select -> and/or
fold.
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
While that fold is clearly not happening [anymore],
we do now have separate test cases for these cases,
so we should be ok to slightly adjust these tests
to not potentially loose test coverage.
As suggested by Hiroshi Yamauchi in
https://reviews.llvm.org/D49179#1159345
llvm-svn: 336912
Summary:
https://bugs.llvm.org/show_bug.cgi?id=38123
This pattern will be produced by Implicit Integer Truncation sanitizer,
https://reviews.llvm.org/D48958https://bugs.llvm.org/show_bug.cgi?id=21530
in unsigned case, therefore it is probably a good idea to improve it.
https://rise4fun.com/Alive/Rny
^ there are more opportunities for folds, i will follow up with them afterwards.
Caveat: this somehow exposes a missing opportunities
in `test/Transforms/InstCombine/icmp-logical.ll`
It seems, the problem is in `foldLogOpOfMaskedICmps()` in `InstCombineAndOrXor.cpp`.
But i'm not quite sure what is wrong, because it calls `getMaskedTypeForICmpPair()`,
which calls `decomposeBitTestICmp()` which should already work for these cases...
As @spatel notes in https://reviews.llvm.org/D49179#1158760,
that code is a rather complex mess, so we'll let it slide.
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: yamauchi, majnemer, t.p.northover, llvm-commits
Differential Revision: https://reviews.llvm.org/D49179
llvm-svn: 336834
It is impossible for (x & INT_MAX) == 0 && x == INT_MAX to ever be true.
While this sort of reasoning should normally live in InstSimplify,
the machinery that derives this result is not trivial to split out.
llvm-svn: 222230
"(icmp op i8 A, B)" is equivalent to "(icmp op i8 (A & 0xff), B)" as a
degenerate case. Allowing this as a "masked" comparison when analysing "(icmp)
&/| (icmp)" allows us to combine them in more cases.
rdar://problem/7625728
llvm-svn: 189931
Even in cases which aren't universally optimisable like "(A & B) != 0 && (A &
C) != 0", the masks can make one of the comparisons completely redundant. In
this case, since we've gone to the effort of spotting masked comparisons we
should combine them.
rdar://problem/7625728
llvm-svn: 189930
