[PATCH][GCC][Arm] Define __ARM_FEATURE_BF16 when +bf16 feature is enabled

[Matthieu Longo]

Hi,

Arm GCC backend does not define __ARM_FEATURE_BF16 when +bf16 is 
specified (via -march option, or target pragma) whereas it is supposed 
to be tested before including arm_bf16.h (as specified in ACLE document: 
https://arm-software.github.io/acle/main/acle.html#arm_bf16h).

gcc/ChangeLog:

        * config/arm/arm-c.cc (arm_cpu_builtins): define __ARM_FEATURE_BF16
        * config/arm/arm.h: define TARGET_BF16

Ok for master ?

Matthieudiff --git a/gcc/config/arm/arm-c.cc b/gcc/config/arm/arm-c.cc
index 
2e181bf7f36bab1209d5358e65d9513541683632..21ca22ac71119eda4ff01709aa95002ca13b1813
 100644
--- a/gcc/config/arm/arm-c.cc
+++ b/gcc/config/arm/arm-c.cc
@@ -425,12 +425,14 @@ arm_cpu_builtins (struct cpp_reader* pfile)
                                   arm_arch_cde_coproc);
 
   def_or_undef_macro (pfile, "__ARM_FEATURE_MATMUL_INT8", TARGET_I8MM);
+
+  def_or_undef_macro (pfile, "__ARM_FEATURE_BF16", TARGET_BF16);
+  def_or_undef_macro (pfile, "__ARM_BF16_FORMAT_ALTERNATIVE",
+                     TARGET_BF16_FP);
   def_or_undef_macro (pfile, "__ARM_FEATURE_BF16_SCALAR_ARITHMETIC",
                      TARGET_BF16_FP);
   def_or_undef_macro (pfile, "__ARM_FEATURE_BF16_VECTOR_ARITHMETIC",
                      TARGET_BF16_SIMD);
-  def_or_undef_macro (pfile, "__ARM_BF16_FORMAT_ALTERNATIVE",
-                     TARGET_BF16_FP || TARGET_BF16_SIMD);
 }
 
 void
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 
2a2207c0ba1acef1c7082c89bf5f542b1466d033..e7a7fc47e606d2ead5f778dca2e63b2e894d0efe
 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -252,10 +252,10 @@ emission of floating point pcs attributes.  */
 #define TARGET_I8MM (TARGET_NEON && arm_arch8_2 && arm_arch_i8mm)
 
 /* FPU supports Brain half-precision floating-point (BFloat16) extension.  */
-#define TARGET_BF16_FP (TARGET_32BIT && TARGET_HARD_FLOAT && TARGET_VFP5 \
-                       && arm_arch8_2 && arm_arch_bf16)
-#define TARGET_BF16_SIMD (TARGET_NEON && TARGET_VFP5 \
-                         && arm_arch8_2 && arm_arch_bf16)
+#define TARGET_BF16 (TARGET_32BIT && TARGET_HARD_FLOAT && arm_arch8_2 \
+                       && TARGET_VFP5 && arm_arch_bf16)
+#define TARGET_BF16_FP (TARGET_BF16)
+#define TARGET_BF16_SIMD (TARGET_BF16 && TARGET_NEON)
 
 /* Q-bit is present.  */
 #define TARGET_ARM_QBIT \