[llvm] [LV] Handle FSub Partial Reductions (PR #191186)

[Sander de Smalen via llvm-commits]

================
@@ -185,4 +185,174 @@ exit:
   ret i32 %sub
 }
 
+define float @fsub_reduction(float %startval, ptr %src1, ptr %src2) #0 {
----------------
sdesmalen-arm wrote:

Could you also add a test with both fadd and fsub?

https://github.com/llvm/llvm-project/pull/191186