[gcc r11-5450] libgfortran: Correct FP feature macro checks

[gcc r11-5450] libgfortran: Correct FP feature macro checks

[Maciej W. Rozycki]

https://gcc.gnu.org/g:c87cce5a339bae3b73f34dbc20409de07caf68da

commit r11-5450-gc87cce5a339bae3b73f34dbc20409de07caf68da
Author: Maciej W. Rozycki <macro@linux-mips.org>
Date:   Thu Nov 26 17:26:43 2020 +0000

    libgfortran: Correct FP feature macro checks
    
    The *_HAS_* floating-point feature macros are defined as 0/1 rather than
    #undef/#define settings by gcc/c-family/c-cppbuiltin.c.  Consequently we
    choose to use infinity and NaN features even with non-IEEE-754 targets
    such as `vax-netbsdelf' that lack them, causing build warnings and
    failures like:
    
    In file included from .../libgfortran/generated/maxval_r4.c:26:
    .../libgfortran/generated/maxval_r4.c: In function 'maxval_r4':
    .../libgfortran/libgfortran.h:292:30: warning: target format does not support infinity
      292 | # define GFC_REAL_4_INFINITY __builtin_inff ()
          |                              ^~~~~~~~~~~~~~
    .../libgfortran/generated/maxval_r4.c:149:19:
    note: in expansion of macro 'GFC_REAL_4_INFINITY'
      149 |         result = -GFC_REAL_4_INFINITY;
          |                   ^~~~~~~~~~~~~~~~~~~
    .../libgfortran/generated/maxval_r4.c: In function 'mmaxval_r4':
    .../libgfortran/libgfortran.h:292:30: warning: target format does not support infinity
      292 | # define GFC_REAL_4_INFINITY __builtin_inff ()
          |                              ^~~~~~~~~~~~~~
    .../libgfortran/generated/maxval_r4.c:363:19:
    note: in expansion of macro 'GFC_REAL_4_INFINITY'
      363 |         result = -GFC_REAL_4_INFINITY;
          |                   ^~~~~~~~~~~~~~~~~~~
    {standard input}: Assembler messages:
    {standard input}:204: Fatal error: Can't relocate expression
    make[3]: *** [Makefile:3358: maxval_r4.lo] Error 1
    
    Correct the checks then for __FLT_HAS_INFINITY__, __DBL_HAS_INFINITY__,
    __LDBL_HAS_INFINITY__, __FLT_HAS_QUIET_NAN__, __DBL_HAS_QUIET_NAN__, and
    __LDBL_HAS_QUIET_NAN__ to match semantics and remove build issues coming
    from the misinterpretation of these macros.
    
            libgfortran/
            * libgfortran.h: Use #if rather than #ifdef with
            __FLT_HAS_INFINITY__, __DBL_HAS_INFINITY__,
            __LDBL_HAS_INFINITY__, __FLT_HAS_QUIET_NAN__,
            __DBL_HAS_QUIET_NAN__, and __LDBL_HAS_QUIET_NAN__.

Diff:
---
 libgfortran/libgfortran.h | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libgfortran/libgfortran.h b/libgfortran/libgfortran.h
index 8c539e0898b..e9c54810f42 100644
--- a/libgfortran/libgfortran.h
+++ b/libgfortran/libgfortran.h
@@ -288,13 +288,13 @@ typedef GFC_UINTEGER_4 gfc_char4_t;
 
 /* M{IN,AX}{LOC,VAL} need also infinities and NaNs if supported.  */
 
-#ifdef __FLT_HAS_INFINITY__
+#if __FLT_HAS_INFINITY__
 # define GFC_REAL_4_INFINITY __builtin_inff ()
 #endif
-#ifdef __DBL_HAS_INFINITY__
+#if __DBL_HAS_INFINITY__
 # define GFC_REAL_8_INFINITY __builtin_inf ()
 #endif
-#ifdef __LDBL_HAS_INFINITY__
+#if __LDBL_HAS_INFINITY__
 # ifdef HAVE_GFC_REAL_10
 #  define GFC_REAL_10_INFINITY __builtin_infl ()
 # endif
@@ -306,13 +306,13 @@ typedef GFC_UINTEGER_4 gfc_char4_t;
 #  endif
 # endif
 #endif
-#ifdef __FLT_HAS_QUIET_NAN__
+#if __FLT_HAS_QUIET_NAN__
 # define GFC_REAL_4_QUIET_NAN __builtin_nanf ("")
 #endif
-#ifdef __DBL_HAS_QUIET_NAN__
+#if __DBL_HAS_QUIET_NAN__
 # define GFC_REAL_8_QUIET_NAN __builtin_nan ("")
 #endif
-#ifdef __LDBL_HAS_QUIET_NAN__
+#if __LDBL_HAS_QUIET_NAN__
 # ifdef HAVE_GFC_REAL_10
 #  define GFC_REAL_10_QUIET_NAN __builtin_nanl ("")
 # endif