In D141910#4112164, @tschuett wrote:

For AArch64 the default alignment is 0? I would have expected 128.

@akyrtzi Thank you for your feedback. Can I land the patch?

Patch rebased

Added changes in clang/lib/AST/CMakeLists.txt to address build issue reported by @akyrtzi .

LGTM

Applied remarks - removed custom parser and printer of nontemporal clause.

Rename OMPIRBuilder function to query SIMD alignment

Scope of changes:

1. Refactored createTargetMachine function.

Reuse existing code.

Applied review remarks.

Hi Johannes,
I was referring to Jan's idea. He proposes to move part of the functionality to the DataLayout class. IMO this option is not the best approach, because DataLayout object does not contain information about subtarget and we cannot determine if SIMD extensions (avx options) are enabled.

I think we cannot not rely on DataLayout to find the maximal SIMD alignment.

@jsjodin thanks for your remark. Let me add some more information to this patch.

1. Refactored OMPIRBuilder method which calculates SIMD alignment. Added optional parameter Type *AlignedValueTy which can be used to define optimal alignment. If this parameter is not specified then, we return the maximal SIMD alignment for given target.
2. Clang still uses suboptimal value because there is no link between clang TargetInfo and LLVM-Type. More information about this decision can be found in previous review which introduced original getSimdDefaultAlign function: https://reviews.llvm.org/D10597?id=28205#inline-85925
3. TargetInfo class contains method: getMaxVectorAlign . This method returns maximal vector alignment for given target. The only difference between original: getMaxVectorAlign and getSimdDefaultAlign is that getSimdDefaultAlign returns 0 alignment for ARM target. I don't know if it is ok, that we assume 0 alignment for ARM targets.
4. Removed getSimdDefaultAlign function.

Yes, we can extend calculations of the default alignment. My primary goal was to move code from clang into llvm without modification of the code logic.

Patch is committed. Link to the commit: https://github.com/llvm/llvm-project/commit/163dbfe869f550bd2d22520fda109876a1122eda . I forgot to add review link in commit message.

Patch rebased

Applied remarks. Added more tests.

Addressed review comments:

1. Modified the way how aligned clause is represented. Use I64ArrayAttr instead of Variadic to represent alignment values
2. Added verifier which checks if aligned clause was properly mapped
3. Added more tests MLIR tests

1. Changed DenseMap to MapVector. MapVector provides that the iteration order is the same as insertion order

1. Update description of AlignedVars argument

1. Modified generation of align assumptions. OMPIRBuilder generates now only assumptions calls. The arguments of the assumption calls are generated by Clang.
2. Added integration test to prove that Clang and OMPIRBuilder support aligned clause
3. Simplification of unit tests -> applying review remarks

Patch rebased.

Remove custom enum for mapping order(concurrent)

Add assert to ensure that alignment value is always specified.

Patch rebased

Patch rebased.

For me the patch is ok, but I think it would be better, if somebody else will also review it.

@peixin What is status of this patch? Are you planning to modify this patch or is it ready for the review?

Applied review remarks. Scope of changes:

Follow up review: https://reviews.llvm.org/D132023 . This review contains Fortran test with simd clause.

Updated test: Do not rely on hardcoded labels. Check if collapsed loop bound is calculated.

@peixin
Thank you for your review. I will apply your remarks in the separate patch which will be Flang specific.

In D131674#3722172, @kiranchandramohan wrote:

As far as possible we should try to have Flang and MLIR OpenMP dialect changes in separate patches.

I would recommend splitting this into two simple patches.

1. Testing the lowering of OpenMP dialect simdloop collapse to LLVM IR. There is an existing test case, simdloop_multi in the translation tests. You need to strengthen it minimally to check the occurrence of collapse. And adding the collapse information to the OpenMP dialect op description.

The relevant code for this came in the patch https://reviews.llvm.org/D118065.

Done. I modified this review so that it contains only OpenMP specific changes.

Add only OpenMP specific changes. Update simd loop MLIR description and strengthen translation test.

Scope of changes:

Applied remarks:
Do not collapse loops inside function responsible for applying SIMD metadirectives
Added special function for loop versioning