On little endian targets prior to Power9, we spill vector registers using a
swapping store (i.e. stdxvd2x saves the vector with the two doublewords in
big endian order regardless of endianness). This is generally not a problem
since we restore them using the corresponding swapping load (lxvd2x). However
if the restore is done by the unwinder, the vector register contains data in
the incorrect order.
This patch fixes that by using Altivec loads/stores for vector saves and
restores in PEI (which keep the order correct) under those specific conditions:
- EH aware function
- Subtarget requires swaps for VSX memops (Little Endian prior to Power9)
Differential revision: https://reviews.llvm.org/D73692
Added four test files to check the existing behaviour of prologue
and epilogue code generation. This patch was done as a setup for
the upcoming patch listed on Phabricator that will change how the
prologue and epilogue work.
The upcoming patch is: https://reviews.llvm.org/D42590
llvm-svn: 353994
Nemanja Ivanovic