From: Andrew Carlotti <andrew.carlotti@arm.com>
Date: Fri, 24 Nov 2023 17:31:51 +0000 (+0000)
Subject: aarch64: Fix +nopredres, +nols64 and +nomops
X-Git-Tag: basepoints/gcc-15~3526
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=06f64b95bafc06c318efc7b6d7c03cd34fe4be78;p=thirdparty%2Fgcc.git

aarch64: Fix +nopredres, +nols64 and +nomops

For native cpu feature detection, certain features have no entry in
/proc/cpuinfo, so have to be assumed to be present whenever the detected
cpu is supposed to support that feature.

However, the logic for this was mistakenly implemented by excluding
these features from part of aarch64_get_extension_string_for_isa_flags.
This function is also used elsewhere when canonicalising explicit
feature sets, which may require removing features that are normally
implied by the specified architecture version.

This change reenables generation of +nopredres, +nols64 and +nomops
during canonicalisation, by relocating the misplaced native cpu
detection logic.

gcc/ChangeLog:

	* common/config/aarch64/aarch64-common.cc
	(struct aarch64_option_extension): Remove unused field.
	(all_extensions): Ditto.
	(aarch64_get_extension_string_for_isa_flags): Remove filtering
	of features without native detection.
	* config/aarch64/driver-aarch64.cc (host_detect_local_cpu):
	Explicitly add expected features that lack cpuinfo detection.

gcc/testsuite/ChangeLog:

	* gcc.target/aarch64/options_set_28.c: New test.
---

diff --git a/gcc/common/config/aarch64/aarch64-common.cc b/gcc/common/config/aarch64/aarch64-common.cc
index c2a6d357c0bc..4d0431d3a2ca 100644
--- a/gcc/common/config/aarch64/aarch64-common.cc
+++ b/gcc/common/config/aarch64/aarch64-common.cc
@@ -149,9 +149,6 @@ struct aarch64_option_extension
   aarch64_feature_flags flags_on;
   /* If this feature is turned off, these bits also need to be turned off.  */
   aarch64_feature_flags flags_off;
-  /* Indicates whether this feature is taken into account during native cpu
-     detection.  */
-  bool native_detect_p;
 };
 
 /* ISA extensions in AArch64.  */
@@ -159,10 +156,9 @@ static constexpr aarch64_option_extension 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_STRING[0]},
+   feature_deps::get_flags_off (feature_deps::root_off_##IDENT)},
 #include "config/aarch64/aarch64-option-extensions.def"
-  {NULL, 0, 0, 0, false}
+  {NULL, 0, 0, 0}
 };
 
 struct processor_name_to_arch
@@ -358,8 +354,7 @@ aarch64_get_extension_string_for_isa_flags
 	/* If either crypto flag needs removing here, then both do.  */
 	flags = flags_crypto;
 
-      if (opt.native_detect_p
-	  && (flags & current_flags & ~isa_flags))
+      if (flags & current_flags & ~isa_flags)
 	{
 	  current_flags &= ~opt.flags_off;
 	  outstr += "+no";
diff --git a/gcc/config/aarch64/driver-aarch64.cc b/gcc/config/aarch64/driver-aarch64.cc
index 8e318892b10a..c18f065aa41e 100644
--- a/gcc/config/aarch64/driver-aarch64.cc
+++ b/gcc/config/aarch64/driver-aarch64.cc
@@ -262,6 +262,7 @@ host_detect_local_cpu (int argc, const char **argv)
   unsigned int n_variants = 0;
   bool processed_exts = false;
   aarch64_feature_flags extension_flags = 0;
+  aarch64_feature_flags unchecked_extension_flags = 0;
   aarch64_feature_flags default_flags = 0;
   std::string buf;
   size_t sep_pos = -1;
@@ -348,7 +349,10 @@ host_detect_local_cpu (int argc, const char **argv)
 	      /* If the feature contains no HWCAPS string then ignore it for the
 		 auto detection.  */
 	      if (val.empty ())
-		continue;
+		{
+		  unchecked_extension_flags |= aarch64_extensions[i].flag;
+		  continue;
+		}
 
 	      bool enabled = true;
 
@@ -380,7 +384,8 @@ host_detect_local_cpu (int argc, const char **argv)
   if (n_cores == 0
       || n_cores > 2
       || (n_cores == 1 && n_variants != 1)
-      || imp == INVALID_IMP)
+      || imp == INVALID_IMP
+      || !processed_exts)
     goto not_found;
 
   /* Simple case, one core type or just looking for the arch. */
@@ -447,6 +452,10 @@ host_detect_local_cpu (int argc, const char **argv)
   if (tune)
     return res;
 
+  /* Add any features that should be be present, but can't be verified using
+     the /proc/cpuinfo "Features" list.  */
+  extension_flags |= unchecked_extension_flags & default_flags;
+
   {
     std::string extension
       = aarch64_get_extension_string_for_isa_flags (extension_flags,
diff --git a/gcc/testsuite/gcc.target/aarch64/options_set_28.c b/gcc/testsuite/gcc.target/aarch64/options_set_28.c
new file mode 100644
index 000000000000..9e63768581e9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/options_set_28.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-march=armv9.3-a+nopredres+nols64+nomops" } */
+
+int main ()
+{
+  return 0;
+}
+
+/* { dg-final { scan-assembler-times {\.arch armv9\.3\-a\+crc\+nopredres\+nols64\+nomops\n} 1 } } */