llvm-project/llvm/test/Transforms/InterleavedAccess
Juneyoung Lee 9f2d9364b0 [CodeGen] Update transformations to use poison for shufflevector/insertelem's initial vector elem
This patch is a part of D93817 and makes transformations in CodeGen use poison for shufflevector/insertelem's initial vector element.

The change in CodeGenPrepare.cpp is fine because the mask of shufflevector should be always zero.
It doesn't touch the second element (which is poison).

The change in InterleavedAccessPass.cpp is also fine becauses the mask is of the form <a, a+m, a+2m, .., a+km> where a+km is smaller than
the size of the first vector operand.
This is guaranteed by the caller of replaceBinOpShuffles, which is lowerInterleavedLoad.
It calls isDeInterleaveMask and isDeInterleaveMaskOfFactor to check the mask is the desirable form.
isDeInterleaveMask has the check that a+km is smaller than the vector size.
To check my understanding, I added an assertion & added a test to show that this optimization doesn't fire in such case.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D94056
2021-01-10 18:03:51 +09:00
..
AArch64 Use unary CreateShuffleVector if possible 2020-12-30 22:36:08 +09:00
ARM Use unary CreateShuffleVector if possible 2020-12-30 22:36:08 +09:00
X86 [CodeGen] Update transformations to use poison for shufflevector/insertelem's initial vector elem 2021-01-10 18:03:51 +09:00