diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b736bb291d4..f17fc102a07 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-12-05  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92803
+	* tree-ssa-forwprop.c (simplify_vector_constructor): Fix
+	invariant vector construction.
+
 2019-12-05  Martin Liska  <mliska@suse.cz>
 
 	PR gcov-profile/91971
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 89066e87356..b075e7e3eab 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-12-05  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/92803
+	* gcc.target/i386/pr92803.c: New testcase.
+
 2019-12-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR fortran/92781
diff --git a/gcc/testsuite/gcc.target/i386/pr92803.c b/gcc/testsuite/gcc.target/i386/pr92803.c
new file mode 100644
index 00000000000..fc8d64efb83
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr92803.c
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wno-psabi -mavx2 -fdump-tree-forwprop1" } */
+
+typedef double v4df __attribute__((vector_size (32)));
+typedef float v8sf __attribute__((vector_size (32)));
+typedef float v4sf __attribute__((vector_size (16)));
+typedef int v4si __attribute__((vector_size (16)));
+typedef double v2df __attribute__((vector_size (16)));
+
+v2df
+foo (v4df x, double *p, v2df y)
+{
+  return (v2df) { x[3], *p };
+}
+
+v4sf
+bar (v4si x, float *p)
+{
+  return (v4sf) { x[0], x[1], x[2], *p };
+}
+
+v4sf
+baz (v4si x)
+{
+  return (v4sf) { x[0], x[1], 3.0f, 1.0f };
+}
+
+v4sf
+barf (v8sf x)
+{
+  return (v4sf) { x[4], x[5], 1.0f, 2.0f };
+}
+
+/* We expect all CTORs to turn into permutes, the FP converting ones
+   to two each with the one with constants possibly elided in the future
+   by converting 3.0f and 1.0f "back" to integers.  */
+/* { dg-final { scan-tree-dump-times "VEC_PERM_EXPR" 6 "forwprop1" } } */
+/* { dg-final { scan-tree-dump-times "VEC_PERM_EXPR" 5 "forwprop1" { xfail *-*-* } } } */
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 4a831242c0e..a27a4cfb379 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2286,24 +2286,28 @@ simplify_vector_constructor (gimple_stmt_iterator *gsi)
       else if (orig[1] == error_mark_node
 	       && one_nonconstant)
 	{
-	  orig[1] = gimple_build_vector_from_val (&stmts, UNKNOWN_LOCATION,
-						  type, one_nonconstant);
 	  /* ???  We can see if we can safely convert to the original
 	     element type.  */
 	  converted_orig1 = conv_code != ERROR_MARK;
+	  orig[1] = gimple_build_vector_from_val (&stmts, UNKNOWN_LOCATION,
+						  converted_orig1
+						  ? type : perm_type,
+						  one_nonconstant);
 	}
       else if (orig[1] == error_mark_node)
 	{
-	  tree_vector_builder vec (type, nelts, 1);
-	  for (unsigned i = 0; i < nelts; ++i)
-	    if (constants[i])
+	  /* ???  See if we can convert the vector to the original type.  */
+	  converted_orig1 = conv_code != ERROR_MARK;
+	  unsigned n = converted_orig1 ? nelts : refnelts;
+	  tree_vector_builder vec (converted_orig1
+				   ? type : perm_type, n, 1);
+	  for (unsigned i = 0; i < n; ++i)
+	    if (i < nelts && constants[i])
 	      vec.quick_push (constants[i]);
 	    else
 	      /* ??? Push a don't-care value.  */
 	      vec.quick_push (one_constant);
 	  orig[1] = vec.build ();
-	  /* ???  See if we can convert the vector to the original type.  */
-	  converted_orig1 = conv_code != ERROR_MARK;
 	}
       tree blend_op2 = NULL_TREE;
       if (converted_orig1)