[PATCH] Check for all known bits on ret in InstCombine
listmail at philipreames.com
Tue Jul 22 10:20:13 PDT 2014
The code change LGTM.
The changes inspires two thoughts:
1) As we've discussed off list and Chandler mentioned, we need to
investigate profitability of various invariant condition propagation
2) When do we remove a llvm.assume? In your test case, you had an
assume which (after the transform) retained a condition about an
otherwise used value (%a). This seems like an obvious case to remove
since we've gotten all the benefit we can from it. Are there other
cases like this we should implement?
p.s. Do you have a wiki or notes page somewhere where we can track
potential enhancements? I worry large parts are getting lost in all the
various review threads.
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