bitint: Fix torture/bitint-14.c on bitint_extended targets [PR117599]

This patch fixes regressions of the gcc.dg/torture/bitint-* tests
caused by r16-3036-ga76a032354ee48 with --enable-checking=all.

The errors are similar to the following:

../../gcc/testsuite/gcc.dg/torture/bitint-14.c:54:1: error: type mismatch in 'array_ref'
<unnamed-signed:63>

unsigned long

_42 = VIEW_CONVERT_EXPR<unsigned long[10]>(r575[i_10])[8];
during GIMPLE pass: bitintlower0
../../gcc/testsuite/gcc.dg/torture/bitint-14.c:54:1: internal compiler error: verify_gimple failed

The first two hunks aren't strictly necessary, I'm just trying to
avoid calling build_qualified_type when it won't be needed.

At least on s390x-linux (tried cross) bitint-14.c doesn't ICE with it
anymore.

Though, I must say the more I look at the limb_access changes, the less
I like the abi_load_p stuff, so I think what we eventually should do instead
is return values with m_limb_type always.
For bitint_extended case (but only if we can prove that the extension there
is for the right precision and right sign) or !write_p just return it,
otherwise cast to lower precision and back to m_limb_type.
And on the other side on stores, for !bitint_extended happily store whatever
the whole m_limb_type value contains, for bitint_extended do the cast to
smaller precision and back on the writes.

2025-09-04  Jakub Jelinek  <jakub@redhat.com>

	PR target/117599
	* gimple-lower-bitint.cc (bitint_large_huge::limb_access): Move
	build_qualified_type calls into the if/else if/else bodies, for
	the last one set ltype to m_limb_type first, drop limb_type_a
	and use ltype instead.

1 files changed, 11 insertions, 13 deletions

diff --git a/gcc/gimple-lower-bitint.cc b/gcc/gimple-lower-bitint.cc
index 1e434ce..9b4d493 100644
--- a/gcc/gimple-lower-bitint.cc
+++ b/gcc/gimple-lower-bitint.cc
@@ -622,12 +622,12 @@ bitint_large_huge::limb_access (tree type, tree var, tree idx, bool write_p,
   tree ltype = (bitint_extended && abi_load_p) ? atype : m_limb_type;
 
   addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (var));
-  if (as != TYPE_ADDR_SPACE (ltype))
-    ltype = build_qualified_type (ltype, TYPE_QUALS (ltype)
-					 | ENCODE_QUAL_ADDR_SPACE (as));
   tree ret;
   if (DECL_P (var) && tree_fits_uhwi_p (idx))
     {
+      if (as != TYPE_ADDR_SPACE (ltype))
+	ltype = build_qualified_type (ltype, TYPE_QUALS (ltype)
+				      | ENCODE_QUAL_ADDR_SPACE (as));
       tree ptype = build_pointer_type (strip_array_types (TREE_TYPE (var)));
       unsigned HOST_WIDE_INT off = tree_to_uhwi (idx) * m_limb_size;
       ret = build2 (MEM_REF, ltype,
@@ -638,6 +638,9 @@ bitint_large_huge::limb_access (tree type, tree var, tree idx, bool write_p,
     }
   else if (TREE_CODE (var) == MEM_REF && tree_fits_uhwi_p (idx))
     {
+      if (as != TYPE_ADDR_SPACE (ltype))
+	ltype = build_qualified_type (ltype, TYPE_QUALS (ltype)
+				      | ENCODE_QUAL_ADDR_SPACE (as));
       ret
 	= build2 (MEM_REF, ltype, unshare_expr (TREE_OPERAND (var, 0)),
 		  size_binop (PLUS_EXPR, TREE_OPERAND (var, 1),
@@ -650,6 +653,10 @@ bitint_large_huge::limb_access (tree type, tree var, tree idx, bool write_p,
     }
   else
     {
+      ltype = m_limb_type;
+      if (as != TYPE_ADDR_SPACE (ltype))
+	ltype = build_qualified_type (ltype, TYPE_QUALS (ltype)
+				      | ENCODE_QUAL_ADDR_SPACE (as));
       var = unshare_expr (var);
       if (TREE_CODE (TREE_TYPE (var)) != ARRAY_TYPE
 	  || !useless_type_conversion_p (m_limb_type,
@@ -657,16 +664,7 @@ bitint_large_huge::limb_access (tree type, tree var, tree idx, bool write_p,
 	{
 	  unsigned HOST_WIDE_INT nelts
 	    = CEIL (tree_to_uhwi (TYPE_SIZE (TREE_TYPE (var))), limb_prec);
-
-	  /* Build the array type with m_limb_type from the right address
-	     space.  */
-	  tree limb_type_a = m_limb_type;
-	  if (as != TYPE_ADDR_SPACE (m_limb_type))
-	    limb_type_a = build_qualified_type (m_limb_type,
-						TYPE_QUALS (m_limb_type)
-						| ENCODE_QUAL_ADDR_SPACE (as));
-
-	  tree atype = build_array_type_nelts (limb_type_a, nelts);
+	  tree atype = build_array_type_nelts (ltype, nelts);
 	  var = build1 (VIEW_CONVERT_EXPR, atype, var);
 	}
       ret = build4 (ARRAY_REF, ltype, var, idx, NULL_TREE, NULL_TREE);