[gcc r11-2949] tree-optimization/96854 - testcase for SLP reduction of two-operator

[gcc r11-2949] tree-optimization/96854 - testcase for SLP reduction of two-operator

[Richard Biener]

https://gcc.gnu.org/g:f089569851ca9c8a81400dd8a159f86636ed20ec

commit r11-2949-gf089569851ca9c8a81400dd8a159f86636ed20ec
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Aug 31 13:36:09 2020 +0200

    tree-optimization/96854 - testcase for SLP reduction of two-operator
    
    This adds the testcase for the already fixed PR.
    
    2020-08-31  Richard Biener  <rguenther@suse.de>
    
            PR tree-optimization/96854
            * gcc.dg/vect/pr96854.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/vect/pr96854.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/vect/pr96854.c b/gcc/testsuite/gcc.dg/vect/pr96854.c
new file mode 100644
index 00000000000..e3980d41303
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr96854.c
@@ -0,0 +1,20 @@
+/* { dg-additional-options "-ffast-math" } */
+
+double _Complex __attribute__((noipa))
+foo (double _Complex acc, const double _Complex *x, const double _Complex* y, int N)
+{
+  for (int c = 0; c < N; ++c)
+    acc -= x[c] * y[c];
+  return acc;
+}
+
+int
+main()
+{
+  static const double _Complex y[] = { 1, 2, };
+  static const double _Complex x[] = { 1, 3, };
+  double _Complex ref = foo (0, x, y, 2);
+  if (__builtin_creal (ref) != -7.)
+    __builtin_abort ();
+  return 0;
+}