diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 24b5c971e5e7..5471c9f40415 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2020-01-10  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/90838
+	* tree-ssa-forwprop.c (simplify_count_trailing_zeroes): Use
+	SCALAR_INT_TYPE_MODE instead of TYPE_MODE as operand of
+	CTZ_DEFINED_VALUE_AT_ZERO.
+
 2020-01-10  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR inline-asm/93027
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index aced6eb2d913..aac31d02b6c2 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -1922,7 +1922,8 @@ simplify_count_trailing_zeroes (gimple_stmt_iterator *gsi)
       tree type = TREE_TYPE (res_ops[0]);
       HOST_WIDE_INT ctzval;
       HOST_WIDE_INT type_size = tree_to_shwi (TYPE_SIZE (type));
-      bool zero_ok = CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (type), ctzval) == 2;
+      scalar_int_mode mode = SCALAR_INT_TYPE_MODE (type);
+      bool zero_ok = CTZ_DEFINED_VALUE_AT_ZERO (mode, ctzval) == 2;
 
       /* Skip if there is no value defined at zero, or if we can't easily
 	 return the correct value for zero.  */