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

[Sam Elliott via llvm-commits]

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@@ -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
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lenary wrote:

I think this says it's present after glibc 2.34? I'm not sure. https://www.gnu.org/software/gnulib/manual/html_node/fminimum_005fnumf.html

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