diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 8a81dbd57f..51e4735520 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -963,6 +963,7 @@ func genValue(v *ssa.Value) {
 		p.From.Type = obj.TYPE_CONST
 		p.From.Offset = v.AuxInt
 		p.To.Type = obj.TYPE_REG
+		p.To.Reg = r
 	case ssa.OpAMD64SBBQcarrymask:
 		r := regnum(v)
 		p := Prog(x86.ASBBQ)