--- gcc/tree-vect-generic.c.jj	2019-07-04 00:18:37.063010439 +0200
+++ gcc/tree-vect-generic.c	2019-07-16 12:40:41.343059690 +0200
@@ -382,8 +382,48 @@ expand_vector_comparison (gimple_stmt_it
   tree t;
   if (!expand_vec_cmp_expr_p (TREE_TYPE (op0), type, code)
       && !expand_vec_cond_expr_p (type, TREE_TYPE (op0), code))
-    t = expand_vector_piecewise (gsi, do_compare, type,
-				 TREE_TYPE (TREE_TYPE (op0)), op0, op1, code);
+    {
+      if (VECTOR_BOOLEAN_TYPE_P (type)
+	  && VECTOR_BOOLEAN_TYPE_P (type)
+	  && SCALAR_INT_MODE_P (TYPE_MODE (type))
+	  && known_lt (GET_MODE_BITSIZE (TYPE_MODE (type)),
+		       TYPE_VECTOR_SUBPARTS (type)
+		       * GET_MODE_BITSIZE (SCALAR_TYPE_MODE
+						(TREE_TYPE (type)))))
+	{
+	  tree inner_type = TREE_TYPE (TREE_TYPE (op0));
+	  tree part_width = TYPE_SIZE (inner_type);
+	  tree index = bitsize_int (0);
+	  int nunits = nunits_for_known_piecewise_op (TREE_TYPE (op0));
+	  int prec = GET_MODE_PRECISION (SCALAR_TYPE_MODE (type));
+	  tree ret_type = build_nonstandard_integer_type (prec, 1);
+	  tree ret_inner_type = boolean_type_node;
+	  int i;
+	  location_t loc = gimple_location (gsi_stmt (*gsi));
+	  t = build_zero_cst (ret_type);
+
+	  if (TYPE_PRECISION (ret_inner_type) != 1)
+	    ret_inner_type = build_nonstandard_integer_type (1, 1);
+	  warning_at (loc, OPT_Wvector_operation_performance,
+		      "vector operation will be expanded piecewise");
+	  for (i = 0; i < nunits;
+	       i++, index = int_const_binop (PLUS_EXPR, index, part_width))
+	    {
+	      tree a = tree_vec_extract (gsi, inner_type, op0, part_width,
+					 index);
+	      tree b = tree_vec_extract (gsi, inner_type, op1, part_width,
+					 index);
+	      tree result = gimplify_build2 (gsi, code, ret_inner_type, a, b);
+	      t = gimplify_build3 (gsi, BIT_INSERT_EXPR, ret_type, t, result,
+				   bitsize_int (i));
+	    }
+	  t = gimplify_build1 (gsi, VIEW_CONVERT_EXPR, type, t);
+	}
+      else
+	t = expand_vector_piecewise (gsi, do_compare, type,
+				     TREE_TYPE (TREE_TYPE (op0)), op0, op1,
+				     code);
+    }
   else
     t = NULL_TREE;
 
@@ -879,6 +919,7 @@ expand_vector_condition (gimple_stmt_ite
   tree a1 = a;
   tree a2 = NULL_TREE;
   bool a_is_comparison = false;
+  bool a_is_scalar_bitmask = false;
   tree b = gimple_assign_rhs2 (stmt);
   tree c = gimple_assign_rhs3 (stmt);
   vec<constructor_elt, va_gc> *v;
@@ -942,6 +983,20 @@ expand_vector_condition (gimple_stmt_ite
   warning_at (loc, OPT_Wvector_operation_performance,
 	      "vector condition will be expanded piecewise");
 
+  if (!a_is_comparison
+      && VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (a))
+      && SCALAR_INT_MODE_P (TYPE_MODE (TREE_TYPE (a)))
+      && known_lt (GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (a))),
+		   TYPE_VECTOR_SUBPARTS (TREE_TYPE (a))
+		   * GET_MODE_BITSIZE (SCALAR_TYPE_MODE
+						(TREE_TYPE (TREE_TYPE (a))))))
+    {
+      a_is_scalar_bitmask = true;
+      int prec = GET_MODE_PRECISION (SCALAR_TYPE_MODE (TREE_TYPE (a)));
+      tree atype = build_nonstandard_integer_type (prec, 1);
+      a = gimplify_build1 (gsi, VIEW_CONVERT_EXPR, atype, a);
+    }
+
   int nunits = nunits_for_known_piecewise_op (type);
   vec_alloc (v, nunits);
   for (i = 0; i < nunits; i++)
@@ -957,6 +1012,14 @@ expand_vector_condition (gimple_stmt_ite
 				       comp_width, comp_index);
 	  aa = fold_build2 (TREE_CODE (a), cond_type, aa1, aa2);
 	}
+      else if (a_is_scalar_bitmask)
+	{
+	  wide_int w = wi::set_bit_in_zero (i, TYPE_PRECISION (TREE_TYPE (a)));
+	  result = gimplify_build2 (gsi, BIT_AND_EXPR, TREE_TYPE (a),
+				    a, wide_int_to_tree (TREE_TYPE (a), w));
+	  aa = fold_build2 (NE_EXPR, boolean_type_node, result,
+			    build_zero_cst (TREE_TYPE (a)));
+	}
       else
 	aa = tree_vec_extract (gsi, cond_type, a, width, index);
       result = gimplify_build3 (gsi, COND_EXPR, inner_type, aa, bb, cc);
@@ -1941,7 +2004,11 @@ expand_vector_operations_1 (gimple_stmt_
   /* A scalar operation pretending to be a vector one.  */
   if (VECTOR_BOOLEAN_TYPE_P (type)
       && !VECTOR_MODE_P (TYPE_MODE (type))
-      && TYPE_MODE (type) != BLKmode)
+      && TYPE_MODE (type) != BLKmode
+      && (TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) != tcc_comparison
+	  || (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (rhs1))
+	      && !VECTOR_MODE_P (TYPE_MODE (TREE_TYPE (rhs1)))
+	      && TYPE_MODE (TREE_TYPE (rhs1)) != BLKmode)))
     return;
 
   /* If the vector operation is operating on all same vector elements
--- gcc/testsuite/gcc.target/i386/avx512f-pr91157.c.jj	2019-07-16 12:54:55.928900526 +0200
+++ gcc/testsuite/gcc.target/i386/avx512f-pr91157.c	2019-07-16 13:01:39.217714434 +0200
@@ -0,0 +1,29 @@
+/* PR tree-optimization/91157 */
+/* { dg-do run { target { avx512f && lp64 } } } */
+/* { dg-options "-O2 -mavx512f -fexceptions -fnon-call-exceptions -fsignaling-nans" } */
+
+#include "avx512f-helper.h"
+
+typedef long double V __attribute__ ((vector_size (4 * sizeof (long double))));
+typedef __int128 W __attribute__ ((vector_size (4 * sizeof (__int128))));
+
+__attribute__((noipa)) W
+foo (V x)
+{
+  return x == 0;
+}
+
+static void
+test_512 (void)
+{
+  V a = { 5.0L, 0.0L, -0.0L, -17.0L };
+  V b = { -0.0L, 16.0L, 0.0L, 18.0L };
+  V c = { 6.0L, 7.0L, 8.0L, 0.0L };
+  W ar = foo (a);
+  W br = foo (b);
+  W cr = foo (c);
+  if (ar[0] != 0 || ar[1] != -1 || ar[2] != -1 || ar[3] != 0
+      || br[0] != -1 || br[1] != 0 || br[2] != -1 || br[3] != 0
+      || cr[0] != 0 || cr[1] != 0 || cr[2] != 0 || cr[3] != -1)
+    __builtin_abort ();
+}
--- gcc/testsuite/gcc.target/i386/avx512bw-pr91157.c.jj	2019-07-16 12:55:11.609659992 +0200
+++ gcc/testsuite/gcc.target/i386/avx512bw-pr91157.c	2019-07-16 13:01:10.438155882 +0200
@@ -0,0 +1,6 @@
+/* PR tree-optimization/91157 */
+/* { dg-do run { target { avx512bw && lp64 } } } */
+/* { dg-options "-O2 -mavx512bw -fexceptions -fnon-call-exceptions -fsignaling-nans" } */
+
+#define AVX512BW
+#include "avx512f-pr91157.c"
