[llvm] [RISCV]: Implemented softening of `FCANONICALIZE` (PR #169234)

[Kevin Per via llvm-commits]

================
@@ -10,6 +11,42 @@ declare float @llvm.fcanonicalize.f32(float)
 declare double @llvm.fcanonicalize.f64(double)
 
 define half @fcanonicalize_f16(half %x) {
+; RV64-SOFT-LABEL: fcanonicalize_f16:
+; RV64-SOFT:       # %bb.0:
+; RV64-SOFT-NEXT:    addi sp, sp, -16
+; RV64-SOFT-NEXT:    .cfi_def_cfa_offset 16
+; RV64-SOFT-NEXT:    sd ra, 8(sp) # 8-byte Folded Spill
+; RV64-SOFT-NEXT:    .cfi_offset ra, -8
+; RV64-SOFT-NEXT:    slli a0, a0, 48
+; RV64-SOFT-NEXT:    srli a0, a0, 48
+; RV64-SOFT-NEXT:    call __extendhfsf2
+; RV64-SOFT-NEXT:    mv a1, a0
+; RV64-SOFT-NEXT:    call fminimum_numf
----------------
kper wrote:

I changed it in the latest commit to MUL * 1.0 to avoid issues with compatibility. 

https://github.com/llvm/llvm-project/pull/169234