Re: [PATCH] fortran: Allow vector math functions only with fast-math [PR 118955]

[Harald Anlauf]

Hi Wilco,

Am 14.01.26 um 7:17 PM schrieb Wilco Dijkstra:

Hi Harald,

the patch does not apply cleanly here.  Can you rebase it?

Sure, see below:

Cheers,
Wilco


v2: Rebased to current trunk

thanks, this works here.

The patch looks good to me.

Regarding your testcase, which is target-specific: you restrict
it to aarch64, but it should in principle work on x64_64 too,
and maybe on several other supported platforms.
I verified that manually, as it is reported as unsupported
when running the testsuite on x86_64-pc-linux-gnu.

So if you - or someone else - find a better choice here, it is
pre-approved.

Thanks for the patch!

Harald

Vector math functions are currently always enabled in Fortran.  This is
incorrect since vector math functions are designed to be Ofast only.
Add a new 'fastmath' option which only accepts vector functions if fast-math
is enabled:

!GCC$ builtin (sin) attributes simd (notinbranch) if('fastmath')

Passes regress.

gcc:
        PR fortran/118955
        * fortran/decl.cc (gfc_match_gcc_builtin): Add 'fastmath' option which
        checks for fast-math before accepting a vector function.
        * fortran/gfortran.texi (!GCC$ builtin): Update documentation.

gcc/testsuite:
        PR fortran/118955
        * gfortran.dg/simd-builtins-9.f90: Add new test.
        * gfortran.dg/simd-builtins-9.h: Likewise.

---

diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
index 
3d0410501b65dd4328815cdedda8c0e24cf2e00f..5348dc1bcacdd1173b37c696f053a2b8f3c66188
 100644
--- a/gcc/fortran/decl.cc
+++ b/gcc/fortran/decl.cc
@@ -29,6 +29,7 @@ along with GCC; see the file COPYING3.  If not see
  #include "parse.h"
  #include "constructor.h"
  #include "target.h"
+#include "flags.h"

/* Macros to access allocate memory for gfc_data_variable,

     gfc_data_value and gfc_data.  */
@@ -12803,9 +12804,17 @@ gfc_match_gcc_builtin (void)

if (gfc_match (" if ( '%n' ) ", target) == MATCH_YES)

      {
-      const char *abi = targetm.get_multilib_abi_name ();
-      if (abi == NULL || strcmp (abi, target) != 0)
-       return MATCH_YES;
+      if (strcmp (target, "fastmath") == 0)
+       {
+         if (!fast_math_flags_set_p (&global_options))
+           return MATCH_YES;
+       }
+      else
+       {
+         const char *abi = targetm.get_multilib_abi_name ();
+         if (abi == NULL || strcmp (abi, target) != 0)
+           return MATCH_YES;
+       }
      }

if (gfc_vectorized_builtins == NULL)

diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index 
c4f39acf6bc31398d010a4165e31b871b39aab20..a930cc1dc9c04348d9ef284789720a79055ca702
 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -3454,6 +3454,13 @@ for the built-in that should be vectorized.  Example 
usage:
  !GCC$ builtin (sinf) attributes simd (notinbranch) if('x86_64')
  @end smallexample

+The special target @code{'fastmath'} is used to specify the vector

+implementation is only valid if fast-math is enabled:
+
+@smallexample
+!GCC$ builtin (exp) attributes simd (notinbranch) if('fastmath')
+@end smallexample
+
  The purpose of the directive is to provide an API among the GCC compiler and
  the GNU C Library which would define vector implementations of math routines.

diff --git a/gcc/testsuite/gfortran.dg/simd-builtins-9.f90 b/gcc/testsuite/gfortran.dg/simd-builtins-9.f90

new file mode 100644
index 
0000000000000000000000000000000000000000..02944e578533afccc90768516cafb473f098f19d
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/simd-builtins-9.f90
@@ -0,0 +1,16 @@
+! { dg-do compile { target { aarch64*-*-linux* } } }
+! { dg-additional-options "-nostdinc -O3 -fpre-include=simd-builtins-9.h 
-fdump-tree-optimized" }
+
+program test_overloaded_intrinsic
+  real(8) :: x8(3200), y8(3200)
+
+  y8 = sin(x8)
+  print *, y8
+
+  x8 = cos(y8)
+  print *, x8
+end
+
+! { dg-final { scan-tree-dump-not "sin.simdclone" "optimized" } } */
+
+! { dg-final { scan-tree-dump "cos.simdclone" "optimized" } } */
diff --git a/gcc/testsuite/gfortran.dg/simd-builtins-9.h 
b/gcc/testsuite/gfortran.dg/simd-builtins-9.h
new file mode 100644
index 
0000000000000000000000000000000000000000..3ca3ea8062c9d1c99ccabc9dd5466befd6e6d4f6
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/simd-builtins-9.h
@@ -0,0 +1,2 @@
+!GCC$ builtin (sin) attributes simd (notinbranch) if('fastmath')
+!GCC$ builtin (cos) attributes simd (notinbranch)