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Fix canFoldInAddressingMode in DAGCombiner.cpp

Authored by fdeferriere on Apr 21 2015, 5:53 AM.



In the function canFoldInAddressingMode, VT is computed as the type of the destination/source of a LOAD/STORE operations, instead of the memory type of the operation.
On targets with a scaling factor on the offset of the LOAD/STORE operations, the function may return false for actually valid cases. This may then prevent the selection of profitable pre or post indexed load/store operations, and instead select pre or post indexed load/store for unprofitable cases.

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fdeferriere retitled this revision from to Fix canFoldInAddressingMode in DAGCombiner.cpp.
fdeferriere updated this object.
fdeferriere edited the test plan for this revision. (Show Details)
fdeferriere added a reviewer: qcolombet.
fdeferriere added a subscriber: Unknown Object (MLST).
qcolombet edited edge metadata.Apr 21 2015, 9:50 AM

Hi François,

Any chance you can add a test case for this change?
I reckon that may be difficult, but if you can come up with something that would be great!


fdeferriere added a comment.EditedApr 24 2015, 3:59 AM

Hi Quentin,

I compiled a number of benches with an LLVM/arm compiler, and looked for differences in code generation with/without this patch, with no success. I also failed to reproduce it on a dedicated test case.I did not try on other targets
Thus, sorry, I won't be able to provide you with a test case for this patch.


qcolombet accepted this revision.Apr 24 2015, 10:02 AM
qcolombet edited edge metadata.

Thanks for trying François.

LGTM then.

I'll commit on your behalf, shortly.


This revision is now accepted and ready to land.Apr 24 2015, 10:02 AM
This revision was automatically updated to reflect the committed changes.