llvm dev - Apr 2020 - Failure while running loop vectorizer

Hi,

While trying to compile my program, I faced problem with Loop Vectorizer which
is trying interleave a load instruction. Error mentioned below

Error message :: void
llvm::InnerLoopVectorizer::vectorizeMemoryInstruction(llvm::Instruction*,
llvm::VPTransformState&, llvm::VPValue*, llvm::VPValue*, llvm::VPValue*):
Assertion `(Decision == LoopVectorizationCostModel::CM_Widen || Decision ==
LoopVectorizationCostModel::CM_Widen_Reverse || Decision ==
LoopVectorizationCostModel::CM_GatherScatter) && "CM decision is
not to widen the memory instruction"' failed.
Source code ::
https://github.com/llvm/llvm-project/blob/master/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp#L2375

I have reduced my program to a shorter test case(vect.ll is attached). The same
problem is reproducible with opt.

Command to reproduce the error: ./opt -loop-vectorize -hexagon-autohvx=1 vect.ll
-S

Based on my analysis, I see that
Decision<https://github.com/llvm/llvm-project/blob/master/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp#L2370>
is getting return value as CM_Interleave but Loop Vectorizer expects either of
the following values: CM_Widen, CM_Widen_Reverse, CM_GatherScatter. Otherwise it
asserts out.

Could you please help in sharing insights on what could be an issue here ?

Thanks,
Abhikrant
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20200414/f60939f2/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: vect.ll
Type: application/octet-stream
Size: 2748 bytes
Desc: vect.ll
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20200414/f60939f2/attachment.obj>