testsuite: Add testcase for already fixed PR [PR123744]

ICE on this testcase started with r16-5169 and got fixed with r16-6937.

2026-01-21  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/123744
	* gcc.target/i386/avx512bw-pr123744.c: New test.

diff --git a/gcc/testsuite/gcc.target/i386/avx512bw-pr123744.c b/gcc/testsuite/gcc.target/i386/avx512bw-pr123744.c
new file mode 100644 (file)
index 0000000..7b178c6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx512bw-pr123744.c
@@ -0,0 +1,19 @@
+/* PR middle-end/123744 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -mavx512bw" } */
+
+int c, d, e;
+long long a;
+signed char *b;
+short f;
+
+void
+foo (short i[][7][7], char j[][7][7])
+{
+  for (int h = 0; h < 128; h++)
+    {
+      c = e ? b[1] : 0;
+      if (a)
+       d = (f ? j[0][0][1] : i[4][4][1]) / 12;
+    }
+}