re PR tree-optimization/92512 (ICE in gimple_op, at gimple.h:2436)

2019-11-15  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92512
	* tree-vect-loop.c (check_reduction_path): Fix operand index
	computability check.  Add check for second use in COND_EXPRs.

	* gcc.dg/torture/pr92512.c: New testcase.

From-SVN: r278293

gcc/ChangeLog

+2019-11-15  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92512
+	* tree-vect-loop.c (check_reduction_path): Fix operand index
+	computability check.  Add check for second use in COND_EXPRs.
+
 2019-11-15  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR target/92515

gcc/testsuite/ChangeLog

 2019-11-15  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/92512
+	* gcc.dg/torture/pr92512.c: New testcase.
+
+2019-11-15  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/92324
 	* gcc.dg/vect/pr92324-4.c: New testcase.
 

gcc/testsuite/gcc.dg/torture/pr92512.c

+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize" } */
+
+long int
+nl (long int fy, int k3, int zr)
+{
+  while (k3 < 1)
+    {
+      if (zr == 0)
+        fy = 0;
+
+      fy *= fy < zr;
+      ++k3;
+    }
+
+  return fy;
+}

gcc/tree-vect-loop.c

@@ -2813,9 +2813,11 @@ pop:
 	  /* The following make sure we can compute the operand index
 	     easily plus it mostly disallows chaining via COND_EXPR condition
 	     operands.  */
-	  || (gimple_assign_rhs1 (use_stmt) != op
-	      && gimple_assign_rhs2 (use_stmt) != op
-	      && gimple_assign_rhs3 (use_stmt) != op))
+	  || (gimple_assign_rhs1_ptr (use_stmt) != path[i].second->use
+	      && (gimple_num_ops (use_stmt) <= 2
+		  || gimple_assign_rhs2_ptr (use_stmt) != path[i].second->use)
+	      && (gimple_num_ops (use_stmt) <= 3
+		  || gimple_assign_rhs3_ptr (use_stmt) != path[i].second->use)))
 	{
 	  fail = true;
 	  break;
@@ -2828,7 +2830,18 @@ pop:
       FOR_EACH_IMM_USE_STMT (op_use_stmt, imm_iter, op)
 	if (!is_gimple_debug (op_use_stmt)
 	    && flow_bb_inside_loop_p (loop, gimple_bb (op_use_stmt)))
-	  cnt++;
+	  {
+	    /* We want to allow x + x but not x < 1 ? x : 2.  */
+	    if (is_gimple_assign (op_use_stmt)
+		&& gimple_assign_rhs_code (op_use_stmt) == COND_EXPR)
+	      {
+		use_operand_p use_p;
+		FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
+		  cnt++;
+	      }
+	    else
+	      cnt++;
+	  }
       if (cnt != 1)
 	{
 	  fail = true;