[gcc(refs/users/marxin/heads/backport-11)] i386: Fix emissing of __builtin_cpu_supports.

[Martin Liska]

https://gcc.gnu.org/g:d4e305e4498039b921070418069a68648188b196

commit d4e305e4498039b921070418069a68648188b196
Author: Martin Liska <mliska@suse.cz>
Date:   Mon Dec 13 15:34:30 2021 +0100

    i386: Fix emissing of __builtin_cpu_supports.
    
            PR target/103661
    
    gcc/ChangeLog:
    
            * config/i386/i386-builtins.c (fold_builtin_cpu): Compare to 0
            as API expects that non-zero values are returned (do that
            it mask == 31).
            For "avx512vbmi2" argument, we return now 1 << 31, which is a
            negative integer value.
    
    (cherry picked from commit 127c7178d5ec502d95862fd823537cbca1a0cb99)

Diff:
---
 gcc/config/i386/i386-builtins.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/config/i386/i386-builtins.c b/gcc/config/i386/i386-builtins.c
index 128bd39816c..59575aea795 100644
--- a/gcc/config/i386/i386-builtins.c
+++ b/gcc/config/i386/i386-builtins.c
@@ -2236,7 +2236,11 @@ fold_builtin_cpu (tree fndecl, tree *args)
       /* Return __cpu_model.__cpu_features[0] & field_val  */
       final = build2 (BIT_AND_EXPR, unsigned_type_node, array_elt,
 		      build_int_cstu (unsigned_type_node, field_val));
-      return build1 (CONVERT_EXPR, integer_type_node, final);
+      if (isa_names_table[i].feature == (INT_TYPE_SIZE - 1))
+	return build2 (NE_EXPR, integer_type_node, final,
+		       build_int_cst (unsigned_type_node, 0));
+      else
+	return build1 (CONVERT_EXPR, integer_type_node, final);
     }
   gcc_unreachable ();
 }