benchtests: Run _Float128 tests only on architectures that support it

__float128 is a non-standard name and is not available on some architectures
(like aarch64 or s390x) even though they may support the standard _Float128
type.  Other architectures (like armv7) don't support quad-precision
floating-point operations at all.

This commit replaces benchtests references to __float128 with _Float128 and
runs the corresponding tests only on architectures that support it.

benchtests/Makefile

@@ -25,7 +25,11 @@ bench-math := acos acosh asin asinh atan atanh cos cosh exp exp2 log log2 \
 	      modf pow rint sin sincos sinh sqrt tan tanh fmin fmax fminf \
 	      fmaxf powf trunc truncf roundeven roundevenf expf exp2f logf \
 	      log2f sincosf sinf cosf isnan isinf isfinite hypot logb logbf \
-	      exp10f expf128 powf128 sinf128
+	      exp10f
+
+ifneq (,$(filter yes,$(float128-fcts) $(float128-alias-fcts)))
+bench-math += expf128 powf128 sinf128
+endif
 
 bench-pthread := pthread_once thread_create
 

benchtests/expf128-inputs

@@ -1,6 +1,6 @@
 ## includes: math.h
-## args: __float128
-## ret: __float128
+## args: _Float128
+## ret: _Float128
 # Random inputs in [-10,10]
 ## name: workload-random.wrf
 0x4.e6f9d6da10d9a422942a89cdfa1p+0L

benchtests/powf128-inputs

@@ -1,6 +1,6 @@
 ## includes: math.h
-## args: __float128:__float128
-## ret: __float128
+## args: _Float128:_Float128
+## ret: _Float128
 # Random inputs in [-10,10] such that x and y are not both negative
 ## name: workload-random.wrf
 0x8.130b31ed5288656428a29cead83p+0L, -0x6.e7ead09b7877a118813b50cfb3c8p+0L

benchtests/sinf128-inputs

@@ -1,6 +1,6 @@
 ## includes: math.h
-## args: __float128
-## ret: __float128
+## args: _Float128
+## ret: _Float128
 # Random inputs in [-10,10]
 ## name: workload-random.wrf
 0x4.e6f9d6da10d9a422942a89cdfa1p+0