i386: Enable _BitInt on x86-64 [PR102989]

The following patch enables _BitInt support on x86-64, the only
target which has _BitInt specified in psABI.

2023-09-06  Jakub Jelinek  <jakub@redhat.com>

	PR c/102989
	* config/i386/i386.cc (classify_argument): Handle BITINT_TYPE.
	(ix86_bitint_type_info): New function.
	(TARGET_C_BITINT_TYPE_INFO): Redefine.

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index 1bc3f11ff078342272a84c151bd3c78e4d0688a9..1cef7ee8f1a38dacc79ace60e06f9602bf7e1c2c 100644 (file)
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -2121,7 +2121,8 @@ classify_argument (machine_mode mode, const_tree type,
        return 0;
     }
 
-  if (type && AGGREGATE_TYPE_P (type))
+  if (type && (AGGREGATE_TYPE_P (type)
+              || (TREE_CODE (type) == BITINT_TYPE && words > 1)))
     {
       int i;
       tree field;
@@ -2270,6 +2271,14 @@ classify_argument (machine_mode mode, const_tree type,
            }
          break;
 
+       case BITINT_TYPE:
+         /* _BitInt(N) for N > 64 is passed as structure containing
+            (N + 63) / 64 64-bit elements.  */
+         if (words > 2)
+           return 0;
+         classes[0] = classes[1] = X86_64_INTEGER_CLASS;
+         return 2;
+
        default:
          gcc_unreachable ();
        }
@@ -24843,6 +24852,25 @@ ix86_get_excess_precision (enum excess_precision_type type)
   return FLT_EVAL_METHOD_UNPREDICTABLE;
 }
 
+/* Return true if _BitInt(N) is supported and fill its details into *INFO.  */
+bool
+ix86_bitint_type_info (int n, struct bitint_info *info)
+{
+  if (!TARGET_64BIT)
+    return false;
+  if (n <= 8)
+    info->limb_mode = QImode;
+  else if (n <= 16)
+    info->limb_mode = HImode;
+  else if (n <= 32)
+    info->limb_mode = SImode;
+  else
+    info->limb_mode = DImode;
+  info->big_endian = false;
+  info->extended = false;
+  return true;
+}
+
 /* Implement PUSH_ROUNDING.  On 386, we have pushw instruction that
    decrements by exactly 2 no matter what the position was, there is no pushb.
 
@@ -25447,6 +25475,8 @@ ix86_run_selftests (void)
 
 #undef TARGET_C_EXCESS_PRECISION
 #define TARGET_C_EXCESS_PRECISION ix86_get_excess_precision
+#undef TARGET_C_BITINT_TYPE_INFO
+#define TARGET_C_BITINT_TYPE_INFO ix86_bitint_type_info
 #undef TARGET_PROMOTE_PROTOTYPES
 #define TARGET_PROMOTE_PROTOTYPES hook_bool_const_tree_true
 #undef TARGET_PUSH_ARGUMENT