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| author | Sanjay Patel <spatel@rotateright.com> | 2017-01-30 16:53:03 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2017-01-30 16:53:03 +0000 |
| commit | 8e644c08ee6e921430e1a1f3e9a8b9dab6c0f8f9 (patch) | |
| tree | c1f9cd5f048efeda94fb0389463cf09da54712eb /llvm/lib/CodeGen | |
| parent | 5d6687da99d945f4b0b1e020b6583515dca530cc (diff) | |
| download | bcm5719-llvm-8e644c08ee6e921430e1a1f3e9a8b9dab6c0f8f9.tar.gz bcm5719-llvm-8e644c08ee6e921430e1a1f3e9a8b9dab6c0f8f9.zip | |
[InstCombine] fixed to propagate 'exact' on lshr
The original shift is bigger, so this may qualify as 'obvious',
but here's an attempt at an Alive-based proof:
Name: exact
Pre: (C1 u< C2)
%a = shl i8 %x, C1
%b = lshr exact i8 %a, C2
=>
%c = lshr exact i8 %x, C2 - C1
%b = and i8 %c, ((1 << width(C1)) - 1) u>> C2
Optimization is correct!
llvm-svn: 293498
Diffstat (limited to 'llvm/lib/CodeGen')
0 files changed, 0 insertions, 0 deletions
