Commit Graph

7 Commits

Author SHA1 Message Date
Nikita Popov 9b5de84e27 [InstCombine] Use IRBuilder to create bitcast
This makes sure that the constant expression bitcast goes through
target-dependent constant folding, and thus avoids an additional
iteration of InstCombine.
2020-03-04 18:28:38 +01:00
Eric Christopher cee313d288 Revert "Temporarily Revert "Add basic loop fusion pass.""
The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552
2019-04-17 04:52:47 +00:00
Eric Christopher a863435128 Temporarily Revert "Add basic loop fusion pass."
As it's causing some bot failures (and per request from kbarton).

This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.

llvm-svn: 358546
2019-04-17 02:12:23 +00:00
Sanjay Patel d1e811979c [InstCombine] reverse bitcast + bitwise-logic canonicalization (PR33138)
There are 2 parts to this patch made simultaneously to avoid a regression.

We're reversing the canonicalization that moves bitwise vector ops before bitcasts. 
We're moving bitwise vector ops *after* bitcasts instead. That's the 1st and 3rd hunks 
of the patch. The motivation is that there's only one fold that currently depends on 
the existing canonicalization (see next), but there are many folds that would 
automatically benefit from the new canonicalization. 
PR33138 ( https://bugs.llvm.org/show_bug.cgi?id=33138 ) shows why/how we have these 
patterns in IR.

There's an or(and,andn) pattern that requires an adjustment in order to continue matching
to 'select' because the bitcast changes position. This match is unfortunately complicated 
because it requires 4 logic ops with optional bitcast and sext ops.

Test diffs:

  1. The bitcast.ll and bitcast-bigendian.ll changes show the most basic difference - 
     bitcast comes before logic.
  2. There are also tests with no diffs in bitcast.ll that verify that we're still doing 
     folds that were enabled by the previous canonicalization.
  3. icmp-xor-signbit.ll shows the payoff. We don't need to adjust existing icmp patterns 
     to look through bitcasts.
  4. logical-select.ll contains several tests for the or(and,andn) --> select fold to 
     verify that we are still handling those cases. The lone diff shows the movement of 
     the bitcast from the new canonicalization rule.

Differential Revision: https://reviews.llvm.org/D33517

llvm-svn: 306011
2017-06-22 15:46:54 +00:00
Sanjay Patel 6232406b34 [InstCombine] add tests to show potential missing folds; NFC
As noted in https://bugs.llvm.org/show_bug.cgi?id=33138 and
the comments, there are multiple ways to view this. If we
choose not to solve this in InstCombine, these tests will
serve as documentation of that choice.

llvm-svn: 303755
2017-05-24 14:56:51 +00:00
Sanjay Patel d3106add77 [InstCombine] allow icmp-xor folds for vectors (PR33138)
This fixes the first part of:
https://bugs.llvm.org/show_bug.cgi?id=33138

More work is needed for the bitcasted variant.

llvm-svn: 303660
2017-05-23 17:29:58 +00:00
Sanjay Patel 7ad3dbe836 [InstCombine] add icmp-xor tests to show vector neglect; NFC
Also, rename the tests and the file, add comments, and add more tests
because there are no existing tests for some of these folds.

These patterns are particularly important for crippled vector ISAs that
have limited compare predicates (PR33138).

llvm-svn: 303652
2017-05-23 16:53:05 +00:00