As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
The original patch was committed here:
rL344609
...and reverted:
rL344612
...because it did not properly check/test data types before calling
ComputeNumSignBits().
The tests that caused bot failures for the previous commit are
over-reaching front-end tests that run the entire -O optimizer
pipeline:
Clang :: CodeGen/builtins-systemz-zvector.c
Clang :: CodeGen/builtins-systemz-zvector2.c
I've added a negative test here to ensure coverage for that case.
The new early exit check also tests the type of the 'B' parameter,
so we don't waste time on matching if either value is unsuitable.
Original commit message:
This is part of solving PR37549:
https://bugs.llvm.org/show_bug.cgi?id=37549
The patterns shown here are a special case of something
that we already convert to select. Using ComputeNumSignBits()
catches that case (but not the more complicated motivating
patterns yet).
The backend has hooks/logic to convert back to logic ops
if that's better for the target.
llvm-svn: 345149
I noticed a missing check and added it at rL344610, but there actually
are codegen tests that will fail without that, so I'll edit those and
submit a fixed patch with more tests.
llvm-svn: 344612
This is part of solving PR37549:
https://bugs.llvm.org/show_bug.cgi?id=37549
The patterns shown here are a special case of something
that we already convert to select. Using ComputeNumSignBits()
catches that case (but not the more complicated motivating
patterns yet).
The backend has hooks/logic to convert back to logic ops
if that's better for the target.
llvm-svn: 344609
The previous code worked with vectors, but it failed when the
vector constants contained undef elements.
The matchers handle those cases.
llvm-svn: 335262
In post-commit review, Eric Christopher notes that many
new MSan warnings are being observed with this patch.
The probable reason is: if 'y' is undef here and we could
evaluate it twice and get different results.
We can't increase the number of uses of a value.
llvm-svn: 333631
Summary:
Finally fixes [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]].
Now that the backend is all done, we can finally fold it!
The canonical unfolded masked merge pattern is
```(x & m) | (y & ~m)```
There is a second, equivalent variant:
```(x | ~m) & (y | m)```
Only one of them (the or-of-and's i think) is canonical.
And if the mask is not a constant, we should fold it to:
```((x ^ y) & M) ^ y```
https://rise4fun.com/Alive/ndQw
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: nicholas, RKSimon, llvm-commits
Differential Revision: https://reviews.llvm.org/D46814
llvm-svn: 333106
The code comments didn't match the code logic, and we didn't actually distinguish the fake unary (not/neg/fneg)
operators from arguments. Adding another level to the weighting scheme provides more structure and can help
simplify the pattern matching in InstCombine and other places.
I fixed regressions that would have shown up from this change in:
rL290067
rL290127
But that doesn't mean there are no pattern-matching logic holes left; some combines may just be missing regression tests.
Should fix:
https://llvm.org/bugs/show_bug.cgi?id=28296
Differential Revision: https://reviews.llvm.org/D27933
llvm-svn: 294049
As noted in the code comment, I don't think we can do the same transform that we do for
*scalar* integers comparisons to *vector* integers comparisons because it might pessimize
the general case.
Exhibit A for an incomplete integer comparison ISA remains x86 SSE/AVX: it only has EQ and GT
for integer vectors.
But we should now recognize all the variants of this construct and produce the optimal code
for the cases shown in:
https://llvm.org/bugs/show_bug.cgi?id=26701
llvm-svn: 262424
Eric Christopher