Commit Graph

6 Commits

Author SHA1 Message Date
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
Teresa Johnson bda581b831 [InstCombine] Add missing test for icmp transformation (NFC)
This was split out of D59378. There was no testing for the EQ case in
foldICmpWithDominatingICmp, add one here.

llvm-svn: 356463
2019-03-19 15:43:56 +00:00
Sanjay Patel baffae91b2 [InstCombine] simplify icmps with same operands based on dominating cmp
The tests here are based on the motivating cases from D54827.

More background:
1. We don't get these cases in general with SimplifyCFG because the root
   of the pattern match is an icmp, not a branch. I'm not sure how often
   we encounter this pattern vs. the seemingly more likely case with 
   branches, but I don't see evidence to leave the minimal pattern
   unoptimized.

2. This has a chance of increasing compile-time because we're using a
   ValueTracking call to handle the match. The motivating cases could be
   handled with a simpler pair of calls to isImpliedTrueByMatchingCmp/
   isImpliedFalseByMatchingCmp, but I saw that we have a more 
   comprehensive wrapper around those, so we might as well use it here
   unless there's evidence that it's significantly slower.

3. Ideally, we'd handle the fold to constants in InstSimplify, but as
   with the existing code here, we could extend this to handle cases
   where the result is not a constant, but a new combined predicate.
   That would mean splitting the logic across the 2 passes and possibly
   duplicating the pattern-matching cost.

4. As mentioned in D54827, this seems like the kind of thing that should
   be handled in Correlated Value Propagation, but that pass is currently
   limited to dealing with instructions with constant operands, so extending
   this bit of InstCombine is the smallest/easiest way to get these patterns 
   optimized.

llvm-svn: 348367
2018-12-05 15:04:00 +00:00
Sanjay Patel 1df1facae2 [InstCombine] add tests for implied simplifications; NFC
Ideally, we would fold all of these in InstSimplify in a
similar way to rL347896, but this is a bit awkward when
we're trying to simplify a compare directly because the
ValueTracking API expects the compare as an input, but
in InstSimplify, we just have the operands of the compare.

Given that we can do transforms besides just simplifications,
we might as well just extend the code in InstCombine (which 
already does simplifications with constant operands).

llvm-svn: 348312
2018-12-04 22:25:33 +00:00
Sanjay Patel 320cf5dde5 [InstCombine] auto-generate full checks for icmp dominator tests; NFC
llvm-svn: 348270
2018-12-04 15:00:35 +00:00