[x86][FastISel] Teach how to select nontemporal stores.
This patch teaches x86 fast-isel how to select nontemporal stores.
On x86, we can use MOVNTI for nontemporal stores of doublewords/quadwords.
Instructions (V)MOVNTPS/PD/DQ can be used for SSE2/AVX aligned nontemporal
vector stores.
Before this patch, fast-isel always selected 'movd/movq' instead of 'movnti'
for doubleword/quadword nontemporal stores. In the case of nontemporal stores
of aligned vectors, fast-isel always selected movaps/movapd/movdqa instead of
movntps/movntpd/movntdq.
With this patch, if we use SSE2/AVX intrinsics for nontemporal stores we now
always get the expected (V)MOVNT instructions.
The lack of fast-isel support for nontemporal stores was spotted when analyzing
the -O0 codegen for nontemporal stores.
Differential Revision: http://reviews.llvm.org/D13698
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@250285 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed