fn1:
x & 0:int @ 0
println(t0) @ 51
return @ 0

fn2:
x & 0:int @ 84
println(t0) @ 97
return @ 0

diff --git a/ssa/builder.go b/ssa/builder.go
index 111bc33..bfb7a2b 100644
--- a/ssa/builder.go
+++ b/ssa/builder.go
@@ -970,9 +970,9 @@ func (b *builder) setCall(fn *Function, e *ast.CallExpr, c *CallCommon) {
 }
 
 // assignOp emits to fn code to perform loc += incr or loc -= incr.
-func (b *builder) assignOp(fn *Function, loc lvalue, incr Value, op token.Token) {
+func (b *builder) assignOp(fn *Function, loc lvalue, incr Value, op token.Token, pos token.Pos) {
        oldv := loc.load(fn)
-       loc.store(fn, emitArith(fn, op, oldv, emitConv(fn, incr, oldv.Type()), loc.typ(), token.NoPos))
+       loc.store(fn, emitArith(fn, op, oldv, emitConv(fn, incr, oldv.Type()), loc.typ(), pos))
 }
 
 // localValueSpec emits to fn code to define all of the vars in the
@@ -1998,7 +1998,7 @@ start:
                        op = token.SUB
                }
                loc := b.addr(fn, s.X, false)
-               b.assignOp(fn, loc, NewConst(exact.MakeInt64(1), loc.typ()), op)
+               b.assignOp(fn, loc, NewConst(exact.MakeInt64(1), loc.typ()), op, s.Pos())
 
        case *ast.AssignStmt:
                switch s.Tok {
@@ -2007,7 +2007,7 @@ start:
 
                default: // +=, etc.
                        op := s.Tok + token.ADD - token.ADD_ASSIGN
-                       b.assignOp(fn, b.addr(fn, s.Lhs[0], false), b.expr(fn, s.Rhs[0]), op)
+                       b.assignOp(fn, b.addr(fn, s.Lhs[0], false), b.expr(fn, s.Rhs[0]), op, s.Pos())
                }
 
        case *ast.GoStmt: