diff --git a/gas/ChangeLog b/gas/ChangeLog
index 057a45fb0f..7cd0a106b3 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,8 @@
+2018-04-26  Jan Beulich  <jbeulich@suse.com>
+
+	* config/tc-i386.c (build_modrm_byte): Extend assertion in
+	vex_3_sources handling to cover more cases.
+
 2018-04-26  Jan Beulich  <jbeulich@suse.com>
 
 	* config/tc-i386.c (build_modrm_byte): Drop code dealing with
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c
index 014720ea3c..7126ca47fd 100644
--- a/gas/config/tc-i386.c
+++ b/gas/config/tc-i386.c
@@ -6591,10 +6591,9 @@ build_modrm_byte (void)
                   && i.tm.opcode_modifier.vexvvvv == VEXXDS
                   && (i.tm.opcode_modifier.veximmext
                       || (i.imm_operands == 1
-                          && i.types[0].bitfield.vec_imm4
-                          && (i.tm.opcode_modifier.vexw == VEXW0
-                              || i.tm.opcode_modifier.vexw == VEXW1)
-                          && i.tm.operand_types[dest].bitfield.regsimd)));
+			  && i.types[0].bitfield.vec_imm4))
+		  && i.tm.opcode_modifier.vexw
+		  && i.tm.operand_types[dest].bitfield.regsimd);
 
       if (i.imm_operands == 0)
         {