Added stress test: libmpfr C struct accessor vs. Racket struct accessor

collects/math/private/bigfloat/mpfr.rkt

@@ -44,7 +44,18 @@
  string->bigfloat
  ;; Main constructor
  bf
- bigfloat-deserialize-info)
+ bigfloat-deserialize-info
+ ;; Low-level stuff
+ mpfr-lib
+ get-mpfr-fun
+ _rnd_t
+ _prec_t
+ _sign_t
+ _exp_t
+ _mpfr_size_limb_t
+ _mpfr
+ _mpfr-pointer
+ (struct-out mpfr))
 
 ;; Arithmetic, comparison, and other functions are provided by the macros that create them
 

collects/tests/racket/stress/mpfr-ffi-call-vs-racket.rkt

@@ -0,0 +1,44 @@
+#lang racket/base
+
+(require ffi/unsafe
+         tests/stress
+         math/private/bigfloat/mpfr)
+
+(define mpfr-get-exp (get-mpfr-fun 'mpfr_get_exp (_fun _mpfr-pointer -> _exp_t)))
+(define mpfr-get-prec (get-mpfr-fun 'mpfr_get_prec (_fun _mpfr-pointer -> _prec_t)))
+(define mpfr-get-signbit (get-mpfr-fun 'mpfr_signbit (_fun _mpfr-pointer -> _int)))
+
+(define (mpfr-signbit x)
+  (if ((mpfr-sign x) . < . 0) 1 0))
+
+(define n 1000000)
+
+(let ([x  (bf 2)])
+  (stress
+   20
+   ["mpfr-get-prec (FFI accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-get-prec x))]
+   ["mpfr-prec (Racket accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-prec x))]))
+
+(let ([x  (bf 2)])
+  (stress
+   20
+   ["mpfr-get-exp (FFI accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-get-exp x))]
+   ["mpfr-exp (Racket accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-exp x))]))
+
+(let ([x  (bf 2)])
+  (stress
+   20
+   ["mpfr-get-signbit (FFI accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-get-signbit x))]
+   ["mpfr-signbit (Racket accessor)"
+    (for ([_  (in-range n)])
+      (mpfr-signbit x))]))