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sanjoy.google (Sanjoy Das (Work Account))
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User Since
Jul 30 2019, 3:04 PM (24 w, 6 d)

Recent Activity

Fri, Jan 10

sanjoy.google removed a reviewer for D72519: [LoopInfo] Support multi edge in getLoopLatch(): sanjoy.google.
Fri, Jan 10, 9:53 AM · Restricted Project

Thu, Jan 9

sanjoy.google added a comment to D71690: [SCEV] get a more accurate range for AddRecExpr with nuw flag.

My understanding is that both the unsigned and signed ranges are valid and we are free to use either one, so using the unsigned one is more beneficial in an unsigned context.

Thu, Jan 9, 8:12 AM · Restricted Project

Dec 19 2019

sanjoy.google requested changes to D71690: [SCEV] get a more accurate range for AddRecExpr with nuw flag.

This needs a specific test case.

Dec 19 2019, 7:24 AM · Restricted Project

Dec 16 2019

sanjoy.google added a comment to D71563: [SCEV] Recognise the hardwareloop "loop.decrement.reg" intrinsic.

Thanks for taking a look!

llvm.loop.decrement.reg is not documented in the langref. Is this a target specific thing?

No, it's a target independent thing, and is generated by the generic Hardwareloop pass. It is defined here:

https://github.com/llvm/llvm-project/blob/ff07fc66d9eef577f3b44716f72e581a18cd9ac9/llvm/include/llvm/IR/Intrinsics.td#L1304

Also, is the entire gamut of optimizations this enables OK? For instance, would it be okay to LFTR replace the trip count of the loop such that it doesn't use the loop_decrement_reg intrinsic anymore?

Hmmm, I don't have a good answer for that yet. First, just to be clear, the llvm.loop.decrement.reg intrinsic is exactly the same as a sub expression, so I think SCEV analysis functions should be okay. But yes, I think I can imagine that SCEV transformations that modify the loop update expression could potentially be problematic. But this is a bit of unexplored territory for me, so first I need to look into what LFTR exactly does. So, I will need to so some homework first, but if we assume for a moment that there will be problematic cases with SCEV transformation modifying the loop update expression (if they would ignore the loop.decremenent intrinsic if there is one present), does that make this approach completely unfeasible, or would you still see possibilities to use the SCEV analysis functions?

Dec 16 2019, 2:11 PM · Restricted Project
sanjoy.google added a comment to D71563: [SCEV] Recognise the hardwareloop "loop.decrement.reg" intrinsic.

llvm.loop.decrement.reg is not documented in the langref. Is this a target specific thing?

Dec 16 2019, 12:25 PM · Restricted Project
sanjoy.google accepted D70156: [APInt] Fix tests that had wrong assumption about sdivs with negative quotient..

lgtm

Dec 16 2019, 7:20 AM · Restricted Project
sanjoy.google accepted D71537: [SCEV] Move ScalarEvolutionExpander.cpp to Transforms/Utils (NFC)..

lgtm

Dec 16 2019, 7:20 AM · Restricted Project

Oct 7 2019

sanjoy.google added a comment to D68194: [LCSSA] Forget values we create LCSSA phis for.

If the SCEV expression is mathematically correct I think this is a problem with SCEV expander. If it is expected to preserve LCSSA it should add the necessary PHIs.

Oct 7 2019, 2:21 PM · Restricted Project
sanjoy.google accepted D68592: [SCEV] Add stricter verification option..

Last time I looked at this I concluded it would be difficult to make enable something like this consistently, but no harm in trying.

Oct 7 2019, 2:16 PM · Restricted Project

Sep 12 2019

sanjoy.google accepted D67417: [LICM/AST] Check if the AliasAny set is removed from the tracker..

lgtm

Sep 12 2019, 10:58 AM · Restricted Project

Sep 4 2019

sanjoy.google accepted D67177: [SCEV] Support SCEVUMinExpr in getRangeRef..

lgtm

Sep 4 2019, 9:27 AM · Restricted Project

Aug 1 2019

sanjoy.google accepted D65596: [SimplifyCFG] Cleanup redundant conditions [NFC]..

lgtm

Aug 1 2019, 4:24 PM · Restricted Project

Jul 31 2019

sanjoy.google accepted D65417: [SCCP] Update condition to avoid overflow..

lgtm with some nits

Jul 31 2019, 11:01 AM · Restricted Project

Jul 30 2019

sanjoy.google added inline comments to D65417: [SCCP] Update condition to avoid overflow..
Jul 30 2019, 3:11 PM · Restricted Project
sanjoy.google edited reviewers for D65417: [SCCP] Update condition to avoid overflow., added: sanjoy.google; removed: sanjoy.
Jul 30 2019, 3:08 PM · Restricted Project