aarch64: Ignore target pragmas while defining intrinsics

Refactor the switcher classes into two separate classes:

- sve_alignment_switcher takes the alignment switching functionality,
  and is used only for ABI correctness when defining sve structure
  types.
- aarch64_target_switcher takes the rest of the functionality of
  aarch64_simd_switcher and sve_switcher, and gates simd/sve specific
  parts upon the specified feature flags.

Additionally, aarch64_target_switcher now adds dependencies of the
specified flags (which adds +fcma and +bf16 to some intrinsic
declarations), and unsets current_target_pragma.

This last change fixes an internal bug where we would sometimes add a
user specified target pragma (stored in current_target_pragma) on top of
an internally specified target architecture while initialising
intrinsics with `#pragma GCC aarch64 "arm_*.h"`.  As far as I can tell, this
has no visible impact at the moment.  However, the unintended target
feature combinations lead to unwanted behaviour in an under-development
patch.

This also fixes a missing Makefile dependency, which was due to
aarch64-sve-builtins.o incorrectly depending on the undefined $(REG_H).
The correct $(REGS_H) dependency is added to the switcher's new source
location.

gcc/ChangeLog:

	* common/config/aarch64/aarch64-common.cc
	(struct aarch64_extension_info): Add field.
	(aarch64_get_required_features): New.
	* config/aarch64/aarch64-builtins.cc
	(aarch64_simd_switcher::aarch64_simd_switcher): Rename to...
	(aarch64_target_switcher::aarch64_target_switcher): ...this,
	and extend to handle sve, nosimd and target pragmas.
	(aarch64_simd_switcher::~aarch64_simd_switcher): Rename to...
	(aarch64_target_switcher::~aarch64_target_switcher): ...this,
	and extend to handle sve, nosimd and target pragmas.
	(handle_arm_acle_h): Use aarch64_target_switcher.
	(handle_arm_neon_h): Rename switcher and pass explicit flags.
	(aarch64_general_init_builtins): Ditto.
	* config/aarch64/aarch64-protos.h
	(class aarch64_simd_switcher): Rename to...
	(class aarch64_target_switcher): ...this, and add new members.
	(aarch64_get_required_features): New prototype.
	* config/aarch64/aarch64-sve-builtins.cc
	(sve_switcher::sve_switcher): Delete
	(sve_switcher::~sve_switcher): Delete
	(sve_alignment_switcher::sve_alignment_switcher): New
	(sve_alignment_switcher::~sve_alignment_switcher): New
	(register_builtin_types): Use alignment switcher
	(init_builtins): Rename switcher.
	(handle_arm_neon_sve_bridge_h): Ditto.
	(handle_arm_sme_h): Ditto.
	(handle_arm_sve_h): Ditto, and use alignment switcher.
	* config/aarch64/aarch64-sve-builtins.h
	(class sve_switcher): Delete.
	(class sme_switcher): Delete.
	(class sve_alignment_switcher): New.
	* config/aarch64/t-aarch64 (aarch64-builtins.o): Add $(REGS_H).
	(aarch64-sve-builtins.o): Remove $(REG_H).

gcc/common/config/aarch64/aarch64-common.cc

@@ -157,6 +157,8 @@ struct aarch64_extension_info
   aarch64_feature_flags flags_on;
   /* If this feature is turned off, these bits also need to be turned off.  */
   aarch64_feature_flags flags_off;
+  /* If this feature remains enabled, these bits must also remain enabled.  */
+  aarch64_feature_flags flags_required;
 };
 
 /* ISA extensions in AArch64.  */
@@ -164,9 +166,10 @@ static constexpr aarch64_extension_info all_extensions[] =
 {
 #define AARCH64_OPT_EXTENSION(NAME, IDENT, C, D, E, FEATURE_STRING) \
   {NAME, AARCH64_FL_##IDENT, feature_deps::IDENT ().explicit_on, \
-   feature_deps::get_flags_off (feature_deps::root_off_##IDENT)},
+   feature_deps::get_flags_off (feature_deps::root_off_##IDENT), \
+   feature_deps::IDENT ().enable},
 #include "config/aarch64/aarch64-option-extensions.def"
-  {NULL, 0, 0, 0}
+  {NULL, 0, 0, 0, 0}
 };
 
 struct aarch64_arch_info
@@ -204,6 +207,18 @@ static constexpr aarch64_processor_info all_cores[] =
   {NULL, aarch64_no_cpu, aarch64_no_arch, 0}
 };
 
+/* Return the set of feature flags that are required to be enabled when the
+   features in FLAGS are enabled.  */
+
+aarch64_feature_flags
+aarch64_get_required_features (aarch64_feature_flags flags)
+{
+  const struct aarch64_extension_info *opt;
+  for (opt = all_extensions; opt->name != NULL; opt++)
+    if (flags & opt->flag_canonical)
+      flags |= opt->flags_required;
+  return flags;
+}
 
 /* Print a list of CANDIDATES for an argument, and try to suggest a specific
    close match.  */

gcc/config/aarch64/aarch64-builtins.cc

@@ -43,6 +43,7 @@
 #include "langhooks.h"
 #include "gimple-iterator.h"
 #include "case-cfn-macros.h"
+#include "regs.h"
 #include "emit-rtl.h"
 #include "stringpool.h"
 #include "attribs.h"
@@ -1877,23 +1878,42 @@ aarch64_scalar_builtin_type_p (aarch64_simd_type t)
   return (t == Poly8_t || t == Poly16_t || t == Poly64_t || t == Poly128_t);
 }
 
-/* Enable AARCH64_FL_* flags EXTRA_FLAGS on top of the base Advanced SIMD
-   set.  */
-aarch64_simd_switcher::aarch64_simd_switcher (aarch64_feature_flags extra_flags)
+/* Temporarily set FLAGS as the enabled target features.  */
+aarch64_target_switcher::aarch64_target_switcher (aarch64_feature_flags flags)
   : m_old_asm_isa_flags (aarch64_asm_isa_flags),
-    m_old_general_regs_only (TARGET_GENERAL_REGS_ONLY)
+    m_old_general_regs_only (TARGET_GENERAL_REGS_ONLY),
+    m_old_target_pragma (current_target_pragma)
 {
-  /* Changing the ISA flags should be enough here.  We shouldn't need to
-     pay the compile-time cost of a full target switch.  */
-  global_options.x_target_flags &= ~MASK_GENERAL_REGS_ONLY;
-  aarch64_set_asm_isa_flags (AARCH64_FL_FP | AARCH64_FL_SIMD | extra_flags);
+  /* Include all dependencies.  */
+  flags = aarch64_get_required_features (flags);
+
+  /* Changing the ISA flags and have_regs_of_mode should be enough here.  We
+     shouldn't need to pay the compile-time cost of a full target switch.  */
+  if (flags & AARCH64_FL_FP)
+    global_options.x_target_flags &= ~MASK_GENERAL_REGS_ONLY;
+  aarch64_set_asm_isa_flags (flags);
+
+  /* Target pragmas are irrelevant when defining intrinsics artificially.  */
+  current_target_pragma = NULL_TREE;
+
+  /* Ensure SVE regs are available if SVE or SME is enabled.  */
+  memcpy (m_old_have_regs_of_mode, have_regs_of_mode, sizeof
+	  (have_regs_of_mode));
+  if (flags & (AARCH64_FL_SVE | AARCH64_FL_SME))
+    for (int i = 0; i < NUM_MACHINE_MODES; ++i)
+      if (aarch64_sve_mode_p ((machine_mode) i))
+	have_regs_of_mode[i] = true;
 }
 
-aarch64_simd_switcher::~aarch64_simd_switcher ()
+aarch64_target_switcher::~aarch64_target_switcher ()
 {
   if (m_old_general_regs_only)
     global_options.x_target_flags |= MASK_GENERAL_REGS_ONLY;
   aarch64_set_asm_isa_flags (m_old_asm_isa_flags);
+  current_target_pragma = m_old_target_pragma;
+
+  memcpy (have_regs_of_mode, m_old_have_regs_of_mode,
+	  sizeof (have_regs_of_mode));
 }
 
 /* Implement #pragma GCC aarch64 "arm_neon.h".
@@ -1903,7 +1923,7 @@ aarch64_simd_switcher::~aarch64_simd_switcher ()
 void
 handle_arm_neon_h (void)
 {
-  aarch64_simd_switcher simd;
+  aarch64_target_switcher switcher (AARCH64_FL_SIMD);
 
   /* Register the AdvSIMD vector tuple types.  */
   for (unsigned int i = 0; i < ARM_NEON_H_TYPES_LAST; i++)
@@ -2353,6 +2373,8 @@ aarch64_init_data_intrinsics (void)
 void
 handle_arm_acle_h (void)
 {
+  aarch64_target_switcher switcher;
+
   aarch64_init_ls64_builtins ();
   aarch64_init_tme_builtins ();
   aarch64_init_memtag_builtins ();
@@ -2446,7 +2468,7 @@ aarch64_general_init_builtins (void)
   aarch64_init_bf16_types ();
 
   {
-    aarch64_simd_switcher simd;
+    aarch64_target_switcher switcher (AARCH64_FL_SIMD);
     aarch64_init_simd_builtins ();
   }
 

gcc/config/aarch64/aarch64-protos.h

@@ -733,15 +733,17 @@ const unsigned int AARCH64_BUILTIN_CLASS = (1 << AARCH64_BUILTIN_SHIFT) - 1;
 
 /* RAII class for enabling enough features to define built-in types
    and implement the arm_neon.h pragma.  */
-class aarch64_simd_switcher
+class aarch64_target_switcher
 {
 public:
-  aarch64_simd_switcher (aarch64_feature_flags extra_flags = 0);
-  ~aarch64_simd_switcher ();
+  aarch64_target_switcher (aarch64_feature_flags flags = 0);
+  ~aarch64_target_switcher ();
 
 private:
   aarch64_feature_flags m_old_asm_isa_flags;
   bool m_old_general_regs_only;
+  tree m_old_target_pragma;
+  bool m_old_have_regs_of_mode[MAX_MACHINE_MODE];
 };
 
 /* Represents the ISA requirements of an intrinsic function, or of some
@@ -1190,6 +1192,7 @@ void aarch64_set_asm_isa_flags (aarch64_feature_flags);
 void aarch64_set_asm_isa_flags (gcc_options *, aarch64_feature_flags);
 bool aarch64_handle_option (struct gcc_options *, struct gcc_options *,
 			     const struct cl_decoded_option *, location_t);
+aarch64_feature_flags aarch64_get_required_features (aarch64_feature_flags);
 void aarch64_print_hint_for_extensions (const char *);
 void aarch64_print_hint_for_arch (const char *);
 void aarch64_print_hint_for_core (const char *);

gcc/config/aarch64/aarch64-sve-builtins.cc

@@ -42,7 +42,6 @@
 #include "emit-rtl.h"
 #include "tree-vector-builder.h"
 #include "stor-layout.h"
-#include "regs.h"
 #include "alias.h"
 #include "gimple-fold.h"
 #include "langhooks.h"
@@ -1296,26 +1295,14 @@ registered_function_hasher::equal (value_type value, const compare_type &key)
   return value->instance == key;
 }
 
-sve_switcher::sve_switcher (aarch64_feature_flags flags)
-  : aarch64_simd_switcher (AARCH64_FL_F16 | AARCH64_FL_SVE | flags)
+sve_alignment_switcher::sve_alignment_switcher ()
 {
-  /* Changing the ISA flags and have_regs_of_mode should be enough here.
-     We shouldn't need to pay the compile-time cost of a full target
-     switch.  */
   m_old_maximum_field_alignment = maximum_field_alignment;
   maximum_field_alignment = 0;
-
-  memcpy (m_old_have_regs_of_mode, have_regs_of_mode,
-	  sizeof (have_regs_of_mode));
-  for (int i = 0; i < NUM_MACHINE_MODES; ++i)
-    if (aarch64_sve_mode_p ((machine_mode) i))
-      have_regs_of_mode[i] = true;
 }
 
-sve_switcher::~sve_switcher ()
+sve_alignment_switcher::~sve_alignment_switcher ()
 {
-  memcpy (have_regs_of_mode, m_old_have_regs_of_mode,
-	  sizeof (have_regs_of_mode));
   maximum_field_alignment = m_old_maximum_field_alignment;
 }
 
@@ -4652,6 +4639,8 @@ register_type_decl (tree type, const char *name)
 static void
 register_builtin_types ()
 {
+  sve_alignment_switcher switcher;
+
 #define DEF_SVE_TYPE(ACLE_NAME, NCHARS, ABI_NAME, SCALAR_TYPE) \
   scalar_types[VECTOR_TYPE_ ## ACLE_NAME] = SCALAR_TYPE;
 #include "aarch64-sve-builtins.def"
@@ -4726,7 +4715,7 @@ register_builtin_types ()
 void
 init_builtins ()
 {
-  sve_switcher sve;
+  aarch64_target_switcher switcher (AARCH64_FL_SVE);
   register_builtin_types ();
   if (in_lto_p)
     {
@@ -4842,7 +4831,8 @@ handle_arm_sve_h (bool function_nulls_p)
       return;
     }
 
-  sve_switcher sve;
+  aarch64_target_switcher switcher (AARCH64_FL_SVE);
+  sve_alignment_switcher alignment_switcher;
 
   /* Define the vector and tuple types.  */
   for (unsigned int type_i = 0; type_i < NUM_VECTOR_TYPES; ++type_i)
@@ -4873,6 +4863,8 @@ handle_arm_neon_sve_bridge_h (bool function_nulls_p)
   if (initial_indexes[arm_sme_handle] == 0)
     handle_arm_sme_h (true);
 
+  aarch64_target_switcher switcher;
+
   /* Define the functions.  */
   function_builder builder (arm_neon_sve_handle, function_nulls_p);
   for (unsigned int i = 0; i < ARRAY_SIZE (neon_sve_function_groups); ++i)
@@ -4900,7 +4892,7 @@ handle_arm_sme_h (bool function_nulls_p)
       return;
     }
 
-  sme_switcher sme;
+  aarch64_target_switcher switcher (AARCH64_FL_SME);
 
   function_builder builder (arm_sme_handle, function_nulls_p);
   for (unsigned int i = 0; i < ARRAY_SIZE (sme_function_groups); ++i)

gcc/config/aarch64/aarch64-sve-builtins.h

@@ -822,24 +822,17 @@ public:
   virtual bool check (function_checker &) const { return true; }
 };
 
-/* RAII class for enabling enough SVE features to define the built-in
-   types and implement the arm_sve.h pragma.  */
-class sve_switcher : public aarch64_simd_switcher
+/* RAII class for temporarily disabling the effect of any -fpack-struct option.
+   This is used to ensure that sve vector tuple types are defined with the
+   correct alignment.  */
+class sve_alignment_switcher
 {
 public:
-  sve_switcher (aarch64_feature_flags = 0);
-  ~sve_switcher ();
+  sve_alignment_switcher ();
+  ~sve_alignment_switcher ();
 
 private:
   unsigned int m_old_maximum_field_alignment;
-  bool m_old_have_regs_of_mode[MAX_MACHINE_MODE];
-};
-
-/* Extends sve_switch enough for defining arm_sme.h.  */
-class sme_switcher : public sve_switcher
-{
-public:
-  sme_switcher () : sve_switcher (AARCH64_FL_SME) {}
 };
 
 extern const type_suffix_info type_suffixes[NUM_TYPE_SUFFIXES + 1];

gcc/config/aarch64/t-aarch64

@@ -50,7 +50,7 @@ endif
 s-mddeps: s-aarch64-tune-md
 
 aarch64-builtins.o: $(srcdir)/config/aarch64/aarch64-builtins.cc $(CONFIG_H) \
-  $(SYSTEM_H) coretypes.h $(TM_H) \
+  $(SYSTEM_H) coretypes.h $(TM_H) $(REGS_H) \
   $(RTL_H) $(TREE_H) expr.h $(TM_P_H) $(RECOG_H) langhooks.h \
   $(DIAGNOSTIC_CORE_H) $(OPTABS_H) \
   $(srcdir)/config/aarch64/aarch64-simd-builtins.def \
@@ -69,7 +69,7 @@ aarch64-sve-builtins.o: $(srcdir)/config/aarch64/aarch64-sve-builtins.cc \
   $(TM_P_H) memmodel.h insn-codes.h $(OPTABS_H) $(RECOG_H) $(DIAGNOSTIC_H) \
   $(EXPR_H) $(BASIC_BLOCK_H) $(FUNCTION_H) fold-const.h $(GIMPLE_H) \
   gimple-iterator.h gimplify.h explow.h $(EMIT_RTL_H) tree-vector-builder.h \
-  stor-layout.h $(REG_H) alias.h gimple-fold.h langhooks.h \
+  stor-layout.h alias.h gimple-fold.h langhooks.h \
   stringpool.h \
   $(srcdir)/config/aarch64/aarch64-sve-builtins.h \
   $(srcdir)/config/aarch64/aarch64-sve-builtins-shapes.h \