Commit Graph

6 Commits

Author SHA1 Message Date
Roman Lebedev d669758d84 [InstCombine] foldICmpWithLowBitMaskedVal(): 'icmp sgt/sle': avoid miscompiles
A precondition 'x != 0' was forgotten by me:
https://rise4fun.com/Alive/JFNP
https://rise4fun.com/Alive/jHvL

These 4 folds with non-constants could be re-enabled,
but for now let's go for the simplest solution.

https://bugs.llvm.org/show_bug.cgi?id=42198

llvm-svn: 362911
2019-06-09 16:30:42 +00:00
Roman Lebedev ff0c99b017 [NFC][InstCombine] Revisit canonicalize-constant-low-bit-mask-and-icmp-s* tests in preparatio for PR42198.
The `icmp sgt`/`icmp sle` variants are, too, miscompiles:
https://rise4fun.com/Alive/JFNP
https://rise4fun.com/Alive/jHvL
A precondition 'x != 0' was forgotten by me.

While ensuring test coverage for `-1`, also add test coverage
for `0` mask. Mask `0` is allowed for all the folds,
mask `-1` is allowed for all the folds with unsigned `icmp` pred.
Constant mask `0` is missed though.

https://bugs.llvm.org/show_bug.cgi?id=42198

llvm-svn: 362910
2019-06-09 16:30:14 +00:00
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
Roman Lebedev 859e14aeaa [InstCombine] Fold x s> x & (-1 >> y) to x s> (-1 >> y)
https://bugs.llvm.org/show_bug.cgi?id=38123
https://rise4fun.com/Alive/I3O

This pattern is not commutative!
We must make sure not to fold the commuted version!

llvm-svn: 337105
2018-07-14 20:08:16 +00:00
Roman Lebedev 62d050d2c4 [NFC][InstCombine] Tests for x s> x & (-1 >> y) to x s> (-1 >> y) fold.
https://bugs.llvm.org/show_bug.cgi?id=38123
https://rise4fun.com/Alive/I3O

This pattern is not commutative!
We must make sure not to fold the commuted version!

llvm-svn: 337104
2018-07-14 20:08:09 +00:00