[llvm] [AArch64][SVE] Add custom lowering for bfloat FMUL (with +bf16) (PR #167502)

[Benjamin Maxwell via llvm-commits]

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@@ -514,61 +514,100 @@ define <vscale x 8 x bfloat> @fmla_nxv8bf16(<vscale x 8 x bfloat> %a, <vscale x
 ;
 
 define <vscale x 2 x bfloat> @fmul_nxv2bf16(<vscale x 2 x bfloat> %a, <vscale x 2 x bfloat> %b) {
-; NOB16B16-LABEL: fmul_nxv2bf16:
-; NOB16B16:       // %bb.0:
-; NOB16B16-NEXT:    lsl z1.s, z1.s, #16
-; NOB16B16-NEXT:    lsl z0.s, z0.s, #16
-; NOB16B16-NEXT:    ptrue p0.d
-; NOB16B16-NEXT:    fmul z0.s, p0/m, z0.s, z1.s
-; NOB16B16-NEXT:    bfcvt z0.h, p0/m, z0.s
-; NOB16B16-NEXT:    ret
+; NOB16B16-NONSTREAMING-LABEL: fmul_nxv2bf16:
+; NOB16B16-NONSTREAMING:       // %bb.0:
+; NOB16B16-NONSTREAMING-NEXT:    movi v2.2d, #0000000000000000
+; NOB16B16-NONSTREAMING-NEXT:    ptrue p0.d
+; NOB16B16-NONSTREAMING-NEXT:    bfmlalb z2.s, z0.h, z1.h
+; NOB16B16-NONSTREAMING-NEXT:    bfcvt z0.h, p0/m, z2.s
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MacDue wrote:

I'll leave this open until https://github.com/llvm/llvm-project/pull/168387#issuecomment-3552658412 is resolved, since maybe this is actually okay for non-strict nodes.

https://github.com/llvm/llvm-project/pull/167502