[PATCH v4 1/3] aarch64: Add march flags for +fp8 arch extensions

[Claudio Bantaloukas]

This introduces the relevant flags to enable access to the fpmr register and 
fp8 intrinsics, which will be added subsequently.

gcc/ChangeLog:

        * config/aarch64/aarch64-option-extensions.def (fp8): New.
        * config/aarch64/aarch64.h (TARGET_FP8): Likewise.
        * doc/invoke.texi (AArch64 Options): Document new -march flags
        and extensions.

gcc/testsuite/ChangeLog:

        * gcc.target/aarch64/acle/fp8.c: New test.
---
 .../aarch64/aarch64-option-extensions.def     |  2 ++
 gcc/config/aarch64/aarch64.h                  |  3 +++
 gcc/doc/invoke.texi                           |  2 ++
 gcc/testsuite/gcc.target/aarch64/acle/fp8.c   | 20 +++++++++++++++++++
 4 files changed, 27 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/aarch64/acle/fp8.c


diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index 42ec0eec31e..6998627f377 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -232,6 +232,8 @@ AARCH64_OPT_EXTENSION("the", THE, (), (), (), "the")
 
 AARCH64_OPT_EXTENSION("gcs", GCS, (), (), (), "gcs")
 
+AARCH64_OPT_EXTENSION("fp8", FP8, (SIMD), (), (), "fp8")
+
 #undef AARCH64_OPT_FMV_EXTENSION
 #undef AARCH64_OPT_EXTENSION
 #undef AARCH64_FMV_FEATURE
diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
index b7e330438d9..2e75c6b81e2 100644
--- a/gcc/config/aarch64/aarch64.h
+++ b/gcc/config/aarch64/aarch64.h
@@ -463,6 +463,9 @@ constexpr auto AARCH64_FL_DEFAULT_ISA_MODE ATTRIBUTE_UNUSED
 				 && (aarch64_tune_params.extra_tuning_flags \
 				     & AARCH64_EXTRA_TUNE_AVOID_PRED_RMW))
 
+/* fp8 instructions are enabled through +fp8.  */
+#define TARGET_FP8 AARCH64_HAVE_ISA (FP8)
+
 /* Standard register usage.  */
 
 /* 31 64-bit general purpose registers R0-R30:
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 86f9b5d1fe5..ef2213b4e84 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -21849,6 +21849,8 @@ Enable support for Armv9.4-a Guarded Control Stack extension.
 Enable support for Armv8.9-a/9.4-a translation hardening extension.
 @item rcpc3
 Enable the RCpc3 (Release Consistency) extension.
+@item fp8
+Enable the fp8 (8-bit floating point) extension.
 
 @end table
 
diff --git a/gcc/testsuite/gcc.target/aarch64/acle/fp8.c b/gcc/testsuite/gcc.target/aarch64/acle/fp8.c
new file mode 100644
index 00000000000..459442be155
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/acle/fp8.c
@@ -0,0 +1,20 @@
+/* Test the fp8 ACLE intrinsics family.  */
+/* { dg-do compile } */
+/* { dg-options "-O1 -march=armv8-a" } */
+
+#include <arm_acle.h>
+
+#ifdef __ARM_FEATURE_FP8
+#error "__ARM_FEATURE_FP8 feature macro defined."
+#endif
+
+#pragma GCC push_options
+#pragma GCC target("arch=armv9.4-a+fp8")
+
+/* We do not define __ARM_FEATURE_FP8 until all
+   relevant features have been added. */
+#ifdef __ARM_FEATURE_FP8
+#error "__ARM_FEATURE_FP8 feature macro defined."
+#endif
+
+#pragma GCC pop_options