[PATCH 1/2] bitint: Use TARGET_ARRAY_MODE for large bitints where target supports it

[Andre Vieira]

This patch ensures we use TARGET_ARRAY_MODE to determine the storage mode of
large bitints that are represented as arrays in memory.  This is required to
support such bitints for aarch64 and potential other targets with similar
bitint specifications.  Existing tests like gcc.dg/torture/bitint-25.c are
affected by this for aarch64 targets.

gcc/ChangeLog:
        stor-layout.cc (layout_type): Use TARGET_ARRAY_MODE for large bitints
        for targets that implement it.
---
 gcc/stor-layout.cc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)


diff --git a/gcc/stor-layout.cc b/gcc/stor-layout.cc
index 4cf249133e9..31da2c123ab 100644
--- a/gcc/stor-layout.cc
+++ b/gcc/stor-layout.cc
@@ -2427,8 +2427,16 @@ layout_type (tree type)
 	  }
 	else
 	  {
-	    SET_TYPE_MODE (type, BLKmode);
 	    cnt = CEIL (TYPE_PRECISION (type), GET_MODE_PRECISION (limb_mode));
+	    machine_mode mode;
+	    /* Some targets use TARGET_ARRAY_MODE to select the mode they use
+	       for arrays with a specific element mode and a specific element
+	       count and we should use this mode for large bitints that are
+	       stored as such arrays.  */
+	    if (!targetm.array_mode (limb_mode, cnt).exists (&mode)
+		|| !targetm.array_mode_supported_p (limb_mode, cnt))
+	      mode = BLKmode;
+	    SET_TYPE_MODE (type, mode);
 	    gcc_assert (info.abi_limb_mode == info.limb_mode
 			|| !info.big_endian == !WORDS_BIG_ENDIAN);
 	  }