[AArch64] PR98657: Fix vec_duplicate creation in SVE's 3

[Andre Vieira (lists) via Gcc-patches]

Hi,

This patch prevents generating a vec_duplicate with illegal predicate.
Regression tested on aarch64-linux-gnu.

OK for trunk?

gcc/ChangeLog:
2021-02-17  Andre Vieira  <andre.simoesdiasvie...@arm.com>

        PR target/98657
        * config/aarch64/aarch64-sve.md: Use 'expand_vector_broadcast' 
to emit vec_duplicate's
        in '<ASHIFT:optab><mode>3' pattern.

gcc/testsuite/ChangeLog:
2021-02-17  Andre Vieira  <andre.simoesdiasvie...@arm.com>

        PR target/98657
        * gcc.target/aarch64/sve/pr98657.c: New test.
diff --git a/gcc/config/aarch64/aarch64-sve.md 
b/gcc/config/aarch64/aarch64-sve.md
index 
608319600318974b414e47285ee1474b041f0e05..7db2938bb84e04d066a7b07574e5cf344a3a8fb6
 100644
--- a/gcc/config/aarch64/aarch64-sve.md
+++ b/gcc/config/aarch64/aarch64-sve.md
@@ -4549,10 +4549,8 @@ (define_expand "<ASHIFT:optab><mode>3"
       }
     else
       {
-       amount = gen_reg_rtx (<MODE>mode);
-       emit_insn (gen_vec_duplicate<mode> (amount,
-                                           convert_to_mode (<VEL>mode,
-                                                            operands[2], 0)));
+       amount = convert_to_mode (<VEL>mode, operands[2], 0);
+       amount = expand_vector_broadcast (<MODE>mode, amount);
       }
     emit_insn (gen_v<optab><mode>3 (operands[0], operands[1], amount));
     DONE;
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr98657.c 
b/gcc/testsuite/gcc.target/aarch64/sve/pr98657.c
new file mode 100644
index 
0000000000000000000000000000000000000000..592af25d7bbc69bc05823d27358f07cd741dbe20
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr98657.c
@@ -0,0 +1,9 @@
+/* PR target/98657  */
+/* { dg-do compile } */
+/* { dg-options "-O3 -msve-vector-bits=256" } */
+extern char a[];
+void b(_Bool c[][18]) {
+  int d;
+  for (int e = 0; e < 23; e++)
+    a[e] = 6 >> c[1][d];
+}