[Bug tree-optimization/104582] [11/12 Regression] Unoptimal code for __negdi2 (and others) from libgcc2 due to unwanted vectorization

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104582

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The costs look weird:
_1 1 times scalar_store costs 12 in body
_5 1 times scalar_store costs 12 in body
_1 1 times vector_store costs 12 in body
<unknown> 1 times vec_construct costs 8 in prologue
vec_construct is certainly more expensive than a store (especially in this case
when it is a store into a TImode variable which isn't addressable and will not
be in memory at all).