From: Richard Biener <rguenther@suse.de>
Date: Tue, 13 Nov 2018 15:07:53 +0000 (+0000)
Subject: re PR tree-optimization/87931 (ICE in vectorizable_reduction, at tree-vect-loop.c... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=41b32876b8a0b8c19b35b768f942bdad1f96f893;p=gcc.git

re PR tree-optimization/87931 (ICE in vectorizable_reduction, at tree-vect-loop.c:6193 since r265876)

2018-11-13  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/87931
	* tree-vect-loop.c (vect_is_simple_reduction): Restrict
	nested cycles we support to latch computations vectorizable_reduction
	handles.

	* gcc.dg/graphite/pr87931.c: New testcase.

From-SVN: r266075
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0b82b956ee4..f9b23f924ae 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-11-13  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/87931
+	* tree-vect-loop.c (vect_is_simple_reduction): Restrict
+	nested cycles we support to latch computations vectorizable_reduction
+	handles.
+
 2018-11-13  Martin Liska  <mliska@suse.cz>
 
 	PR tree-optimization/87885
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 70d9e76834d..e61f978798e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-11-13  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/87931
+	* gcc.dg/graphite/pr87931.c: New testcase.
+
 2018-11-13  Martin Liska  <mliska@suse.cz>
 
 	PR sanitizer/87930
diff --git a/gcc/testsuite/gcc.dg/graphite/pr87931.c b/gcc/testsuite/gcc.dg/graphite/pr87931.c
new file mode 100644
index 00000000000..9ef8610ffa6
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr87931.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-tree-copy-prop -fgraphite-identity" } */
+
+#define N 40
+#define M 128
+float in[N+M];
+float coeff[M];
+float fir_out[N];
+
+void fir ()
+{
+  int i,j,k;
+  float diff;
+
+  for (i = 0; i < N; i++) {
+    diff = 0;
+    for (j = 0; j < M; j++) {
+      diff += in[j+i]*coeff[j];
+    }
+    fir_out[i] = diff;
+  }
+}
diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index a6f0b823dda..1a39b3bb4e9 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -2976,6 +2976,22 @@ vect_is_simple_reduction (loop_vec_info loop_info, stmt_vec_info phi_info,
 
   if (nested_in_vect_loop && !check_reduction)
     {
+      /* FIXME: Even for non-reductions code generation is funneled
+	 through vectorizable_reduction for the stmt defining the
+	 PHI latch value.  So we have to artificially restrict ourselves
+	 for the supported operations.  */
+      switch (get_gimple_rhs_class (code))
+	{
+	case GIMPLE_BINARY_RHS:
+	case GIMPLE_TERNARY_RHS:
+	  break;
+	default:
+	  /* Not supported by vectorizable_reduction.  */
+	  if (dump_enabled_p ())
+	    report_vect_op (MSG_MISSED_OPTIMIZATION, def_stmt,
+			    "nested cycle: not handled operation: ");
+	  return NULL;
+	}
       if (dump_enabled_p ())
 	report_vect_op (MSG_NOTE, def_stmt, "detected nested cycle: ");
       return def_stmt_info;