Fix -mbranch-cost range.

2017-06-29  Martin Liska  <mliska@suse.cz>

	* config/i386/i386.opt: Change range from [1,5] to [0,5].

From-SVN: r249773

gcc/ChangeLog

+2017-06-29  Martin Liska  <mliska@suse.cz>
+
+	* config/i386/i386.opt: Change range from [1,5] to [0,5].
+
 2017-06-29  Yury Gribov  <tetra2005@gmail.com>
 
 	PR bootstrap/80565

gcc/config/i386/i386.opt

@@ -267,7 +267,7 @@ EnumValue
 Enum(asm_dialect) String(att) Value(ASM_ATT)
 
 mbranch-cost=
-Target RejectNegative Joined UInteger Var(ix86_branch_cost) IntegerRange(1, 5)
+Target RejectNegative Joined UInteger Var(ix86_branch_cost) IntegerRange(0, 5)
 Branches are this expensive (arbitrary units).
 
 mlarge-data-threshold=