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kavon / ghc-llvm

improvements to llvm to support functional-language compilers, e.g., ghc
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Craft C example of CSE during isel producing worse code #19

Open kavon opened 7 years ago

kavon commented 7 years ago

IMO, the CSE happening in isel as a side-effect of the design of SDNode is not a good idea. It causes the store/load of a constant across a call, when it's better to rematieralize it.

kavon commented 7 years ago

the pre-isel pass i added works around this, but maybe its worth filing a report with upsteam.

Probably worth waiting for gobal isel to land though?