An analysis of real world code turned up a number of patterns with BUILD_VECTOR
of nodes resulting from operations on extracted vector elements for which we
produce poor code. This addresses those cases. No attempt is made for
completeness as that would entail a large amount of work for something that
there is no evidence of in real code.
Differential revision: https://reviews.llvm.org/D72660
This is a follow up patch from https://reviews.llvm.org/D57857 to handle
extract_subvector v4f32. For cases where we fpext of v2f32 to v2f64 from
extract_subvector we currently generate on P9 the following:
lxv 0, 0(3)
xxsldwi 1, 0, 0, 1
xscvspdpn 2, 0
xxsldwi 3, 0, 0, 3
xxswapd 0, 0
xscvspdpn 1, 1
xscvspdpn 3, 3
xscvspdpn 0, 0
xxmrghd 0, 0, 3
xxmrghd 1, 2, 1
stxv 0, 0(4)
stxv 1, 0(5)
This patch custom lower it to the following sequence:
lxv 0, 0(3) # load the v4f32 <w0, w1, w2, w3>
xxmrghw 2, 0, 0 # Produce the following vector <w0, w0, w1, w1>
xxmrglw 3, 0, 0 # Produce the following vector <w2, w2, w3, w3>
xvcvspdp 2, 2 # FP-extend to <d0, d1>
xvcvspdp 3, 3 # FP-extend to <d2, d3>
stxv 2, 0(5) # Store <d0, d1> (%vecinit11)
stxv 3, 0(4) # Store <d2, d3> (%vecinit4)
Differential Revision: https://reviews.llvm.org/D61961
llvm-svn: 372029
