aarch64: PR target/115457 Implement missing __ARM_FEATURE_BF16 macro

The ACLE asks the user to test for __ARM_FEATURE_BF16 before using the
<arm_bf16.h> header but GCC doesn't set this up.
LLVM does, so this is an inconsistency between the compilers.

This patch enables that macro for TARGET_BF16_FP.
Bootstrapped and tested on aarch64-none-linux-gnu.

gcc/

	PR target/115457
	* config/aarch64/aarch64-c.c (aarch64_update_cpp_builtins):
	Define __ARM_FEATURE_BF16 for TARGET_BF16_FP.

gcc/testsuite/

	PR target/115457
	* gcc.target/aarch64/acle/bf16_feature.c: New test.

Signed-off-by: Kyrylo Tkachov <ktkachov@nvidia.com>
(cherry picked from commit c10942134fa759843ac1ed1424b86fcb8e6368ba)

diff --git a/gcc/config/aarch64/aarch64-c.c b/gcc/config/aarch64/aarch64-c.c
index 05869463e4ba5569726853b079d0f49e38a22d39..f6d90affd3744004483c2c819587dd532e3d2d4e 100644 (file)
--- a/gcc/config/aarch64/aarch64-c.c
+++ b/gcc/config/aarch64/aarch64-c.c
@@ -200,6 +200,8 @@ aarch64_update_cpp_builtins (cpp_reader *pfile)
                        "__ARM_FEATURE_BF16_VECTOR_ARITHMETIC", pfile);
   aarch64_def_or_undef (TARGET_BF16_FP,
                        "__ARM_FEATURE_BF16_SCALAR_ARITHMETIC", pfile);
+  aarch64_def_or_undef (TARGET_BF16_FP,
+                       "__ARM_FEATURE_BF16", pfile);
   aarch64_def_or_undef (AARCH64_ISA_RCPC, "__ARM_FEATURE_RCPC", pfile);
 
   /* Not for ACLE, but required to keep "float.h" correct if we switch

diff --git a/gcc/testsuite/gcc.target/aarch64/acle/bf16_feature.c b/gcc/testsuite/gcc.target/aarch64/acle/bf16_feature.c
new file mode 100644 (file)
index 0000000..96584b4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/acle/bf16_feature.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+
+#pragma GCC target "+bf16"
+#ifndef __ARM_FEATURE_BF16
+#error "__ARM_FEATURE_BF16 is not defined but should be!"
+#endif
+
+void
+foo (void) {}
+