Juneyoung Lee 71add9c8eb [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
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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