[gcc r12-1705] Fix ICE for vpexpand*.

[hongtao Liu <liuhongt@gcc.gnu.org>]

https://gcc.gnu.org/g:b6efffa552cee6a20a58c91e5f41466c5715d73d

commit r12-1705-gb6efffa552cee6a20a58c91e5f41466c5715d73d
Author: liuhongt <hongtao.liu@intel.com>
Date:   Wed Apr 28 14:52:59 2021 +0800

    Fix ICE for vpexpand*.
    
    gcc/ChangeLog
    
            PR target/100310
            * config/i386/i386-expand.c
            (ix86_expand_special_args_builtin): Keep constm1_operand only
            if it satisfies insn's operand predicate.
    
    gcc/testsuite/ChangeLog
    
            PR target/100310
            * gcc.target/i386/pr100310.c: New test.

Diff:
---
 gcc/config/i386/i386-expand.c            |  5 +++--
 gcc/testsuite/gcc.target/i386/pr100310.c | 12 ++++++++++++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index 8f4e4e4d884..cc2eaeed8df 100644
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -10969,11 +10969,12 @@ ix86_expand_special_args_builtin (const struct builtin_description *d,
 
 	  op = fixup_modeless_constant (op, mode);
 
-	  /* NB: 3-operands load implied it's a mask load,
+	  /* NB: 3-operands load implied it's a mask load or v{p}expand*,
 	     and that mask operand shoud be at the end.
 	     Keep all-ones mask which would be simplified by the expander.  */
 	  if (nargs == 3 && i == 2 && klass == load
-	      && constm1_operand (op, mode))
+	      && constm1_operand (op, mode)
+	      && insn_p->operand[i].predicate (op, mode))
 	    ;
 	  else if (GET_MODE (op) == mode || GET_MODE (op) == VOIDmode)
 	    op = copy_to_mode_reg (mode, op);
diff --git a/gcc/testsuite/gcc.target/i386/pr100310.c b/gcc/testsuite/gcc.target/i386/pr100310.c
new file mode 100644
index 00000000000..54ace18531b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr100310.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-mavx512f -O2" } */
+#include <immintrin.h>
+
+double *p;
+volatile __m512d x;
+volatile __mmask8 m;
+
+void foo()
+{
+  x = _mm512_mask_expandloadu_pd (x, 255, p);
+}