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| author | Sanjay Patel <spatel@rotateright.com> | 2018-10-26 21:05:14 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2018-10-26 21:05:14 +0000 |
| commit | cc9e401e3cf11bf353bf7b2734f89fcb74f16d95 (patch) | |
| tree | d423c18faa74513d583f237d5493ebc7dc189f92 /llvm/lib/Support/VirtualFileSystem.cpp | |
| parent | 7bf85f5c8dd1a6d49581eaf1fdd489eac79e2115 (diff) | |
| download | llvm-cc9e401e3cf11bf353bf7b2734f89fcb74f16d95.zip llvm-cc9e401e3cf11bf353bf7b2734f89fcb74f16d95.tar.gz llvm-cc9e401e3cf11bf353bf7b2734f89fcb74f16d95.tar.bz2 | |
[ValueTracking] peek through shuffles in ComputeNumSignBits (PR37549)
The motivating case is from PR37549:
https://bugs.llvm.org/show_bug.cgi?id=37549
The analysis improvement allows us to form a vector 'select' out of
bitwise logic (the use of ComputeNumSignBits was added at rL345149).
The smaller test shows another InstCombine improvement - we use
ComputeNumSignBits to add 'nsw' to shift-left. But the negative
test shows an example where we must not add 'nsw' - when the shuffle
mask contains undef elements.
Differential Revision: https://reviews.llvm.org/D53659
llvm-svn: 345429
Diffstat (limited to 'llvm/lib/Support/VirtualFileSystem.cpp')
0 files changed, 0 insertions, 0 deletions