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| author | Sanjay Patel <spatel@rotateright.com> | 2018-08-01 17:17:08 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2018-08-01 17:17:08 +0000 |
| commit | 8aac22e06a196541961cd6d6cc46ffd4f39b60c3 (patch) | |
| tree | ce54e012d6bc3a7d3f1e697f5ab4cdd9fdb69bbd /llvm/lib/CodeGen/IndirectBrExpandPass.cpp | |
| parent | 0bb8d83c89321c0bfe955c5e2b2069a2870912d4 (diff) | |
| download | bcm5719-llvm-8aac22e06a196541961cd6d6cc46ffd4f39b60c3.tar.gz bcm5719-llvm-8aac22e06a196541961cd6d6cc46ffd4f39b60c3.zip | |
[SelectionDAG] fix bug in translating funnel shift with non-power-of-2 type
The bug is visible in the constant-folded x86 tests. We can't use the
negated shift amount when the type is not power-of-2:
https://rise4fun.com/Alive/US1r
...so in that case, use the regular lowering that includes a select
to guard against a shift-by-bitwidth. This path is improved by only
calculating the modulo shift amount once now.
Also, improve the rotate (with power-of-2 size) lowering to use
a negate rather than subtract from bitwidth. This improves the
codegen whether we have a rotate instruction or not (although
we can still see that we're not matching to a legal rotate in
all cases).
llvm-svn: 338592
Diffstat (limited to 'llvm/lib/CodeGen/IndirectBrExpandPass.cpp')
0 files changed, 0 insertions, 0 deletions
