[Mips] Add additional half float tests (NFC)

For llvm#110199.

Author: yingopq

llvm/test/CodeGen/Mips/fp16-promote.ll

@@ -260,3 +260,65 @@ define void @test_vec_fptrunc_double(<4 x double> %a, ptr %p) nounwind {
   ret void
 }
 
+define half @test_fadd_fadd(half %a, half %b, half %c) nounwind {
+; CHECK-LIBCALL-LABEL: test_fadd_fadd:
+; CHECK-LIBCALL:       # %bb.0:
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, -32
+; CHECK-LIBCALL-NEXT:    sdc1 $f20, 24($sp) # 8-byte Folded Spill
+; CHECK-LIBCALL-NEXT:    sw $ra, 20($sp) # 4-byte Folded Spill
+; CHECK-LIBCALL-NEXT:    sw $16, 16($sp) # 4-byte Folded Spill
+; CHECK-LIBCALL-NEXT:    move $16, $6
+; CHECK-LIBCALL-NEXT:    mov.s $f20, $f12
+; CHECK-LIBCALL-NEXT:    jal __gnu_f2h_ieee
+; CHECK-LIBCALL-NEXT:    mov.s $f12, $f14
+; CHECK-LIBCALL-NEXT:    jal __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT:    move $4, $2
+; CHECK-LIBCALL-NEXT:    mov.s $f21, $f0
+; CHECK-LIBCALL-NEXT:    jal __gnu_f2h_ieee
+; CHECK-LIBCALL-NEXT:    mov.s $f12, $f20
+; CHECK-LIBCALL-NEXT:    jal __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT:    move $4, $2
+; CHECK-LIBCALL-NEXT:    add.s $f20, $f0, $f21
+; CHECK-LIBCALL-NEXT:    jal __gnu_f2h_ieee
+; CHECK-LIBCALL-NEXT:    mtc1 $16, $f12
+; CHECK-LIBCALL-NEXT:    jal __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT:    move $4, $2
+; CHECK-LIBCALL-NEXT:    add.s $f0, $f20, $f0
+; CHECK-LIBCALL-NEXT:    lw $16, 16($sp) # 4-byte Folded Reload
+; CHECK-LIBCALL-NEXT:    lw $ra, 20($sp) # 4-byte Folded Reload
+; CHECK-LIBCALL-NEXT:    ldc1 $f20, 24($sp) # 8-byte Folded Reload
+; CHECK-LIBCALL-NEXT:    jr $ra
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, 32
+  %d = fadd half %a, %b
+  %e = fadd half %d, %c
+  ret half %e
+}
+
+define half @to_half(i16 %bits) nounwind {
+; CHECK-LIBCALL-LABEL: to_half:
+; CHECK-LIBCALL:       # %bb.0:
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, -24
+; CHECK-LIBCALL-NEXT:    sw $ra, 20($sp) # 4-byte Folded Spill
+; CHECK-LIBCALL-NEXT:    jal __gnu_h2f_ieee
+; CHECK-LIBCALL-NEXT:    nop
+; CHECK-LIBCALL-NEXT:    lw $ra, 20($sp) # 4-byte Folded Reload
+; CHECK-LIBCALL-NEXT:    jr $ra
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, 24
+  %f = bitcast i16 %bits to half
+  ret half %f
+}
+
+define i16 @from_half(half %f) nounwind {
+; CHECK-LIBCALL-LABEL: from_half:
+; CHECK-LIBCALL:       # %bb.0:
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, -24
+; CHECK-LIBCALL-NEXT:    sw $ra, 20($sp) # 4-byte Folded Spill
+; CHECK-LIBCALL-NEXT:    jal __gnu_f2h_ieee
+; CHECK-LIBCALL-NEXT:    nop
+; CHECK-LIBCALL-NEXT:    andi $2, $2, 65535
+; CHECK-LIBCALL-NEXT:    lw $ra, 20($sp) # 4-byte Folded Reload
+; CHECK-LIBCALL-NEXT:    jr $ra
+; CHECK-LIBCALL-NEXT:    addiu $sp, $sp, 24
+  %bits = bitcast half %f to i16
+  ret i16 %bits
+}