[PATCH] fix hybrid SLP discovery debug stmt issue

[Richard Biener]

This properly skips debug USE_STMTs when looking for non-SLP sinks.

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2020-11-23  Richard Biener  <rguent...@suse.de>

        * tree-vect-slp.c (maybe_push_to_hybrid_worklist): Skip
        debug stmts.

        * g++.dg/vect/simd-12.cc: New testcase.
---
 gcc/testsuite/g++.dg/vect/simd-12.cc | 36 ++++++++++++++++++++++++++++
 gcc/tree-vect-slp.c                  |  2 ++
 2 files changed, 38 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/vect/simd-12.cc

diff --git a/gcc/testsuite/g++.dg/vect/simd-12.cc 
b/gcc/testsuite/g++.dg/vect/simd-12.cc
new file mode 100644
index 00000000000..a3f18d385ef
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/simd-12.cc
@@ -0,0 +1,36 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ffast-math -g" } */
+
+template <typename> class complex;
+template <typename _Tp> complex<_Tp> operator+(complex<_Tp>, complex<_Tp> __y) 
{
+  complex<_Tp> __r;
+  __r += __y;
+  return __r;
+}
+template <typename _Tp> complex<_Tp> operator*(complex<_Tp>, complex<_Tp> __y) 
{
+  complex<_Tp> __r;
+  __r *= __y;
+  return __r;
+}
+template <> class complex<double> {
+public:
+  void operator+=(complex __z) { _M_value += __z.__rep(); }
+  void operator*=(complex __z) {
+    _Complex __t = __z.__rep();
+    _M_value *= __t;
+  }
+  _Complex __rep() { return _M_value; }
+  _Complex _M_value;
+};
+template <typename> class Vector {
+  void equ();
+  complex<double> *val;
+};
+template <typename Number> void Vector<Number>::equ() {
+  Number c;
+  for (int i; i; ++i) {
+    complex<double> __trans_tmp_2 = c * val[i];
+    val[i] = val[i] + __trans_tmp_2;
+  }
+}
+template class Vector<complex<double> >;
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 59a8630f74a..da3ef433161 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -3191,6 +3191,8 @@ maybe_push_to_hybrid_worklist (vec_info *vinfo,
       any_def = true;
       FOR_EACH_IMM_USE_FAST (use_p, iter2, DEF_FROM_PTR (def_p))
        {
+         if (is_gimple_debug (USE_STMT (use_p)))
+           continue;
          stmt_vec_info use_info = vinfo->lookup_stmt (USE_STMT (use_p));
          /* An out-of loop use means this is a loop_vect sink.  */
          if (!use_info)
-- 
2.26.2