[PATCH] D48828: [InstSimplify] fold extracting from std::pair

[Hiroshi Inoue via Phabricator via llvm-commits]

inouehrs added a comment.

@lebedev.ri  @spatel 
Thak you so much for the advices. I avoid mentioning about C++ in the comment.

@lebedev.ri

> Use ./utils/update_test_checks.py please.

I updated the test cases using update_test_checks.py and moved them into existing ll files since `pair.ll` is no longer good file name.

@spatel 
The simplified test cases can be optimized by current instcombine pass. But to enable jump threading for std::pair, which is the original motivation of the patch, we must apply this folding over a phi node as discussed in https://reviews.llvm.org/D44626. 
Executing jump threading pass again after CFG simplification may catch this opportunity. But I think it is better to do jump threading early to help other optimizers.


https://reviews.llvm.org/D48828