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| author | Chris Lattner <sabre@nondot.org> | 2010-08-27 22:53:44 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-08-27 22:53:44 +0000 |
| commit | 5275ba2e7da02086fb9f757f14c5adf1e65a94ae (patch) | |
| tree | 409b539215f3192ae9c1676a89f5ffd5cbcfb8a1 /lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | |
| parent | 8cd320aab9573cbba94c7bcfdd33b43306fff024 (diff) | |
| download | external_llvm-5275ba2e7da02086fb9f757f14c5adf1e65a94ae.zip external_llvm-5275ba2e7da02086fb9f757f14c5adf1e65a94ae.tar.gz external_llvm-5275ba2e7da02086fb9f757f14c5adf1e65a94ae.tar.bz2 | |
Enhance the shift propagator to handle the case when you have:
A = shl x, 42
...
B = lshr ..., 38
which can be transformed into:
A = shl x, 4
...
iff we can prove that the would-be-shifted-in bits
are already zero. This eliminates two shifts in the testcase
and allows eliminate of the whole i128 chain in the real example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112314 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
0 files changed, 0 insertions, 0 deletions