[PATCH] i386: Don't use AVX512F integral masks for V*TImode [PR94438]

[Jakub Jelinek via Gcc-patches]

Hi!

The ix86_get_mask_mode hook uses int mask for 512-bit vectors or 128/256-bit
vectors with AVX512VL (that is correct), and only for V*[SD][IF]mode if not
AVX512BW (also correct), but with AVX512BW it would stop checking the
elem_size altogether and pretend the hw has masking support for V*TImode
etc., which it doesn't.  That can lead to various ICEs later on.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2020-04-02  Jakub Jelinek  <ja...@redhat.com>

        PR target/94438
        * config/i386/i386.c (ix86_get_mask_mode): Only use int mask for 
elem_size
        1, 2, 4 and 8.

        * gcc.target/i386/avx512bw-pr94438.c: New test.
        * gcc.target/i386/avx512vlbw-pr94438.c: New test.

--- gcc/config/i386/i386.c.jj   2020-03-17 13:50:52.916933781 +0100
+++ gcc/config/i386/i386.c      2020-04-02 17:14:00.202672882 +0200
@@ -21771,7 +21771,9 @@ ix86_get_mask_mode (machine_mode data_mo
   if ((TARGET_AVX512F && vector_size == 64)
       || (TARGET_AVX512VL && (vector_size == 32 || vector_size == 16)))
     {
-      if (elem_size == 4 || elem_size == 8 || TARGET_AVX512BW)
+      if (elem_size == 4
+         || elem_size == 8
+         || (TARGET_AVX512BW && (elem_size == 1 || elem_size == 2)))
        return smallest_int_mode_for_size (nunits);
     }
 
--- gcc/testsuite/gcc.target/i386/avx512bw-pr94438.c.jj 2020-04-02 
17:18:37.374587069 +0200
+++ gcc/testsuite/gcc.target/i386/avx512bw-pr94438.c    2020-04-02 
17:17:15.928787665 +0200
@@ -0,0 +1,13 @@
+/* PR target/94438 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-mavx512bw" } */
+
+typedef __attribute__ ((__vector_size__ (4 * sizeof (__int128)))) __int128 V;
+void bar (V);
+
+void
+foo (V w)
+{
+  V v = 0 <= (0 >= w);
+  bar (v);
+}
--- gcc/testsuite/gcc.target/i386/avx512vlbw-pr94438.c.jj       2020-04-02 
17:18:08.272016069 +0200
+++ gcc/testsuite/gcc.target/i386/avx512vlbw-pr94438.c  2020-04-02 
17:16:25.302533951 +0200
@@ -0,0 +1,13 @@
+/* PR target/94438 */
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-mavx512bw -mavx512vl" } */
+
+typedef __attribute__ ((__vector_size__ (sizeof (__int128)))) __int128 V;
+void bar (V);
+
+void
+foo (V w)
+{
+  V v = 0 <= (0 >= w);
+  bar (v);
+}

        Jakub