[gcc r14-4868] vect: Allow same precision for bit-precision conversions.

[gcc r14-4868] vect: Allow same precision for bit-precision conversions.

[Robin Dapp]

https://gcc.gnu.org/g:32b74c9e1d46932a4bbb1f46353bfc43c702c20a

commit r14-4868-g32b74c9e1d46932a4bbb1f46353bfc43c702c20a
Author: Robin Dapp <rdapp@ventanamicro.com>
Date:   Sun Oct 15 22:36:59 2023 +0200

    vect: Allow same precision for bit-precision conversions.
    
    In PR111794 we miss a vectorization because on riscv type precision and
    mode precision differ for mask types.  We can still vectorize when
    allowing assignments with the same precision for dest and source which
    is what this patch does.
    
    gcc/ChangeLog:
    
            PR tree-optimization/111794
            * tree-vect-stmts.cc (vectorizable_assignment): Add
            same-precision exception for dest and source.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/riscv/rvv/autovec/slp-mask-1.c: New test.
            * gcc.target/riscv/rvv/autovec/slp-mask-run-1.c: New test.

Diff:
---
 .../gcc.target/riscv/rvv/autovec/slp-mask-1.c      | 18 +++++++++++++
 .../gcc.target/riscv/rvv/autovec/slp-mask-run-1.c  | 31 ++++++++++++++++++++++
 gcc/tree-vect-stmts.cc                             | 12 +++++----
 3 files changed, 56 insertions(+), 5 deletions(-)

diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-1.c
new file mode 100644
index 000000000000..ee1baa58d634
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-std=gnu99 -O3 -march=rv64gcv -mabi=lp64d --param=riscv-autovec-preference=scalable -fdump-tree-slp-details" } */
+
+void
+__attribute__ ((noipa))
+f (int *restrict x, short *restrict y, int *restrict res)
+{
+  res[0] = x[0] == 1 & y[0] == 2;
+  res[1] = x[1] == 1 & y[1] == 2;
+  res[2] = x[2] == 1 & y[2] == 2;
+  res[3] = x[3] == 1 & y[3] == 2;
+  res[4] = x[4] == 1 & y[4] == 2;
+  res[5] = x[5] == 1 & y[5] == 2;
+  res[6] = x[6] == 1 & y[6] == 2;
+  res[7] = x[7] == 1 & y[7] == 2;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorizing stmts using SLP" 1 "slp2" } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-run-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-run-1.c
new file mode 100644
index 000000000000..b3469c41c878
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/slp-mask-run-1.c
@@ -0,0 +1,31 @@
+/* { dg-do run { target { riscv_v } } } */
+/* { dg-additional-options "-std=gnu99 -O3 -march=rv64gcv -mabi=lp64d --param=riscv-autovec-preference=scalable" } */
+
+#include <malloc.h>
+#include <stdio.h>
+
+#include "slp-mask-1.c"
+
+#define SZ 8
+
+__attribute__ ((optimize ("1")))
+int main ()
+{
+  int *a = malloc (SZ * sizeof (*a));
+  short *b = malloc (SZ * sizeof (*b));
+  int *res = malloc (SZ * sizeof (*res));
+  int *ref = malloc (SZ * sizeof (*ref));
+
+  for (int i = 0; i < SZ; i++)
+    {
+      a[i] = i & 1;
+      b[i] = 2;
+      ref[i] = a[i] == 1 & b[i] == 2;
+    }
+
+  f (a, b, res);
+
+  for (int i = 0; i < SZ; i++)
+    if (res[i] != ref[i])
+      __builtin_abort ();
+}
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 99ba75e98c0d..a9200767f67a 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -6058,14 +6058,16 @@ vectorizable_assignment (vec_info *vinfo,
       /* But a conversion that does not change the bit-pattern is ok.  */
       && !(INTEGRAL_TYPE_P (TREE_TYPE (scalar_dest))
 	   && INTEGRAL_TYPE_P (TREE_TYPE (op))
-	   && (TYPE_PRECISION (TREE_TYPE (scalar_dest))
+	   && (((TYPE_PRECISION (TREE_TYPE (scalar_dest))
 	       > TYPE_PRECISION (TREE_TYPE (op)))
-	   && TYPE_UNSIGNED (TREE_TYPE (op))))
+	     && TYPE_UNSIGNED (TREE_TYPE (op)))
+	       || (TYPE_PRECISION (TREE_TYPE (scalar_dest))
+		   == TYPE_PRECISION (TREE_TYPE (op))))))
     {
       if (dump_enabled_p ())
-        dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
-                         "type conversion to/from bit-precision "
-                         "unsupported.\n");
+	dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+			 "type conversion to/from bit-precision "
+			 "unsupported.\n");
       return false;
     }