| commit | 2675b0c8abccc2f62796385f4d4090e4db0732a4 | [log] [tgz] |
|---|---|---|
| author | Sanjay Patel <spatel@rotateright.com> | Mon Jun 24 22:35:26 2019 +0000 |
| committer | Sanjay Patel <spatel@rotateright.com> | Mon Jun 24 22:35:26 2019 +0000 |
| tree | 51c83ba471628a2da07a7b87ad6f924de5d0a07a | |
| parent | 8950d0a1f0620bb11f049dcdafb2b257c3c91d8f [diff] |
[InstCombine] squash is-not-power-of-2 using ctpop This is the Demorgan'd 'not' of the pattern handled in: D63660 / rL364153 This is another intermediate IR step towards solving PR42314: https://bugs.llvm.org/show_bug.cgi?id=42314 We can test if a value is not a power-of-2 using ctpop(X) > 1, so combining that with an is-zero check of the input is the same as testing if not exactly 1 bit is set: (X == 0) || (ctpop(X) u> 1) --> ctpop(X) != 1 llvm-svn: 364246