[PATCH] sccvn: Don't use SCALAR_INT_TYPE_MODE on BLKmode BITINT_TYPEs [PR113459]

[Jakub Jelinek <jakub@redhat.com>]

Hi!

sccvn uses GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type)) for INTEGER_TYPEs,
most likely because that is what native_{interpret,encode}_int used.
This obviously doesn't work for larger BITINT_TYPEs which have BLKmode
and the above ICEs on those.  native_{interpret,encode}_int checks whether
the BITINT_TYPE is medium/large/huge (i.e. an array of 2+ ABI limbs)
and uses TYPE_SIZE_UNIT for that case, otherwise SCALAR_INT_TYPE_MODE like
for the INTEGER_TYPE case.

The following patch instead just uses SCALAR_INT_TYPE_MODE for non-BLKmode
TYPE_MODE and TYPE_SIZE_UNIT otherwise.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2024-01-19  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/113459
	* tree-ssa-sccvn.cc (vn_walk_cb_data::push_partial_def): Use
	TREE_INT_CST_LOW of TYPE_SIZE_UNIT rather than GET_MODE_SIZE
	of SCALAR_INT_TYPE_MODE if type has BLKmode.
	(vn_reference_lookup_3): Likewise.  Formatting fix.

	* gcc.dg/bitint-73.c: New test.

--- gcc/tree-ssa-sccvn.cc.jj	2024-01-03 11:51:42.361580881 +0100
+++ gcc/tree-ssa-sccvn.cc	2024-01-18 12:39:52.789606975 +0100
@@ -2287,7 +2287,12 @@ vn_walk_cb_data::push_partial_def (pd_da
 				    BITS_PER_UNIT
 				    - (maxsizei % BITS_PER_UNIT));
       if (INTEGRAL_TYPE_P (type))
-	sz = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type));
+	{
+	  if (TYPE_MODE (type) != BLKmode)
+	    sz = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type));
+	  else
+	    sz = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (type));
+	}
       if (sz > needed_len)
 	{
 	  memcpy (this_buffer + (sz - needed_len), buffer, needed_len);
@@ -2967,8 +2972,10 @@ vn_reference_lookup_3 (ao_ref *ref, tree
 	    }
 	  else
 	    {
-	      unsigned buflen = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (vr->type)) + 1;
-	      if (INTEGRAL_TYPE_P (vr->type))
+	      unsigned buflen
+		= TREE_INT_CST_LOW (TYPE_SIZE_UNIT (vr->type)) + 1;
+	      if (INTEGRAL_TYPE_P (vr->type)
+		  && TYPE_MODE (vr->type) != BLKmode)
 		buflen = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (vr->type)) + 1;
 	      unsigned char *buf = XALLOCAVEC (unsigned char, buflen);
 	      memset (buf, TREE_INT_CST_LOW (gimple_call_arg (def_stmt, 1)),
@@ -3165,7 +3172,12 @@ vn_reference_lookup_3 (ao_ref *ref, tree
 			 offset + maxsize - 1.  */
 		      HOST_WIDE_INT sz = maxsizei / BITS_PER_UNIT;
 		      if (INTEGRAL_TYPE_P (type))
-			sz = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type));
+			{
+			  if (TYPE_MODE (type) != BLKmode)
+			    sz = GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (type));
+			  else
+			    sz = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (type));
+			}
 		      amnt = ((unsigned HOST_WIDE_INT) offset2i + size2i
 			      - offseti - maxsizei) % BITS_PER_UNIT;
 		      if (amnt)
--- gcc/testsuite/gcc.dg/bitint-73.c.jj	2024-01-18 12:29:07.586634031 +0100
+++ gcc/testsuite/gcc.dg/bitint-73.c	2024-01-18 12:28:42.406986342 +0100
@@ -0,0 +1,18 @@
+/* PR tree-optimization/113459 */
+/* { dg-do compile { target bitint } } */
+/* { dg-options "-std=c23 -O2" } */
+
+#if __BITINT_MAXWIDTH__ >= 129
+# define N 129
+#else
+# define N 63
+#endif
+
+_BitInt(N) a;
+
+_BitInt(N)
+foo (void)
+{
+  __builtin_memset (&a, 6, sizeof a);
+  return a;
+}

	Jakub