maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
364,411 Commits 23 Branches 0 Tags 2.2 GiB
Commit Graph

10 Commits

Author SHA1 Message Date
Sanjay Patel ec06b38130 [InstCombine] canonicalize 'not' ops before logical shifts 
This reverses the existing transform that would uniformly canonicalize any 'xor' after any shift. In the case of logical shifts, that turns a 'not' into an arbitrary 'xor' with constant, and that's probably not as good for analysis, SCEV, or codegen.

The SCEV motivating case is discussed in:
http://bugs.llvm.org/PR47136

There's an analysis motivating case at:
http://bugs.llvm.org/PR38781

I did draft a patch that would do the same for 'ashr' but that's questionable because it's just swapping the position of a 'not' and uncovers at least 2 missing folds that we would probably need to deal with as preliminary steps.

Alive proofs:
https://rise4fun.com/Alive/BBV

  Name: shift right of 'not'
  Pre: C2 == (-1 u>> C1)
  %a = lshr i8 %x, C1
  %r = xor i8 %a, C2
  =>
  %n = xor i8 %x, -1
  %r = lshr i8 %n, C1

  Name: shift left of 'not'
  Pre: C2 == (-1 << C1)
  %a = shl i8 %x, C1
  %r = xor i8 %a, C2
  =>
  %n = xor i8 %x, -1
  %r = shl i8 %n, C1

  Name: ashr of 'not'
  %a = ashr i8 %x, C1
  %r = xor i8 %a, -1
  =>
  %n = xor i8 %x, -1
  %r = ashr i8 %n, C1

Differential Revision: https://reviews.llvm.org/D86243
 2020-08-22 09:38:13 -04:00
Sanjay Patel 455688e293 [InstCombine] add tests for shifted xor; NFC 2020-08-19 13:48:35 -04:00
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
Suyog Sarda f8516e1662 Use FileCheck instead of grep. Change by Ankur Garg. 
Differential Revision: http://reviews.llvm.org/D6430

llvm-svn: 222879
 2014-11-27 11:22:49 +00:00
Dan Gohman 72a13d2476 Use opt -S instead of piping bitcode output through llvm-dis. 
llvm-svn: 81257
 2009-09-08 22:34:10 +00:00
Dan Gohman 9737a63ed8 Change these tests to feed the assembly files to opt directly, instead 
of using llvm-as, now that opt supports this.

llvm-svn: 81226
 2009-09-08 16:50:01 +00:00
Dan Gohman f9dd170e36 Convert tests using "| wc -l | grep ..." to use the count script. 
llvm-svn: 41097
 2007-08-15 13:36:28 +00:00
Reid Spencer 91948d4cad For PR1319: 
Upgrade tests to work with new llvm.exp version of llvm_runtest.

llvm-svn: 36013
 2007-04-14 20:13:02 +00:00
Chris Lattner 1ada0693ab new testcase 
llvm-svn: 35144
 2007-03-18 22:50:57 +00:00