Fix reduc_index calculation in vectorizable_condition

Fixes ICEs in gcc.target/aarch64/sve/clastb*.

2019-10-29  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-vect-stmts.c (vectorizable_condition): Get the reduction
	index for the COND_EXPR from stmt_info rather than reduc_info.

From-SVN: r277567

gcc/ChangeLog

+2019-10-29  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* tree-vect-stmts.c (vectorizable_condition): Get the reduction
+	index for the COND_EXPR from stmt_info rather than reduc_info.
+
 2019-10-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/65930

gcc/tree-vect-stmts.c

@@ -9882,7 +9882,7 @@ vectorizable_condition (stmt_vec_info stmt_info, gimple_stmt_iterator *gsi,
 	return false;
       reduc_info = info_for_reduction (stmt_info);
       reduction_type = STMT_VINFO_REDUC_TYPE (reduc_info);
-      reduc_index = STMT_VINFO_REDUC_IDX (reduc_info);
+      reduc_index = STMT_VINFO_REDUC_IDX (stmt_info);
       gcc_assert (reduction_type != EXTRACT_LAST_REDUCTION
 		  || reduc_index != -1);
     }