}
}
- // Next, process values in the block.
+ // Next, eliminate any redundant nil checks in this block.
i := 0
for _, v := range b.Values {
b.Values[i] = v
f.Config.Warnl(v.Line, "removed nil check")
}
v.reset(OpUnknown)
+ // TODO: f.freeValue(v)
i--
continue
}
- // Record the fact that we know ptr is non nil, and remember to
- // undo that information when this dominator subtree is done.
- nonNilValues[ptr.ID] = true
- work = append(work, bp{op: ClearPtr, ptr: ptr})
}
}
for j := i; j < len(b.Values); j++ {
}
b.Values = b.Values[:i]
+ // Finally, find redundant nil checks for subsequent blocks.
+ // Note that we can't add these until the loop above is done, as the
+ // values in the block are not ordered in any way when this pass runs.
+ // This was the cause of issue #18725.
+ for _, v := range b.Values {
+ if v.Op != OpNilCheck {
+ continue
+ }
+ ptr := v.Args[0]
+ // Record the fact that we know ptr is non nil, and remember to
+ // undo that information when this dominator subtree is done.
+ nonNilValues[ptr.ID] = true
+ work = append(work, bp{op: ClearPtr, ptr: ptr})
+ }
+
// Add all dominated blocks to the work list.
for w := sdom[node.block.ID].child; w != nil; w = sdom[w.ID].sibling {
work = append(work, bp{op: Work, block: w})
)
func f1() {
- _ = *intp // ERROR "generated nil check"
+ _ = *intp // ERROR "removed nil check"
// This one should be removed but the block copy needs
// to be turned into its own pseudo-op in order to see
// the indirect.
- _ = *arrayp // ERROR "generated nil check"
+ _ = *arrayp // ERROR "removed nil check"
// 0-byte indirect doesn't suffice.
// we don't registerize globals, so there are no removed.* nil checks.
- _ = *array0p // ERROR "generated nil check"
_ = *array0p // ERROR "removed nil check"
+ _ = *array0p // ERROR "generated nil check"
- _ = *intp // ERROR "removed nil check"
+ _ = *intp // ERROR "generated nil check"
_ = *arrayp // ERROR "removed nil check"
_ = *structp // ERROR "generated nil check"
_ = *emptyp // ERROR "generated nil check"
- _ = *arrayp // ERROR "removed nil check"
+ _ = *arrayp // ERROR "generated nil check"
}
func f2() {
empty1p *Empty1
)
- _ = *intp // ERROR "generated nil check"
- _ = *arrayp // ERROR "generated nil check"
- _ = *array0p // ERROR "generated nil check"
- _ = *array0p // ERROR "removed.* nil check"
_ = *intp // ERROR "removed.* nil check"
_ = *arrayp // ERROR "removed.* nil check"
+ _ = *array0p // ERROR "removed.* nil check"
+ _ = *array0p // ERROR "generated nil check"
+ _ = *intp // ERROR "generated nil check"
+ _ = *arrayp // ERROR "removed.* nil check"
_ = *structp // ERROR "generated nil check"
_ = *emptyp // ERROR "generated nil check"
- _ = *arrayp // ERROR "removed.* nil check"
+ _ = *arrayp // ERROR "generated nil check"
_ = *bigarrayp // ERROR "generated nil check" ARM removed nil check before indirect!!
_ = *bigstructp // ERROR "generated nil check"
_ = *empty1p // ERROR "generated nil check"
// x wasn't going to change across the function call.
// But it's a little complex to do and in practice doesn't
// matter enough.
- _ = x[9999] // ERROR "removed nil check"
+ _ = x[9999] // ERROR "generated nil check" // TODO: fix
}
func f3a() {
x := fx10k()
y := fx10k()
z := fx10k()
- _ = &x[9] // ERROR "generated nil check"
- y = z
_ = &x[9] // ERROR "removed.* nil check"
+ y = z
+ _ = &x[9] // ERROR "generated nil check"
x = y
_ = &x[9] // ERROR "generated nil check"
}
func f3b() {
x := fx10k()
y := fx10k()
- _ = &x[9] // ERROR "generated nil check"
+ _ = &x[9] // ERROR "removed.* nil check"
y = x
_ = &x[9] // ERROR "removed.* nil check"
x = y
- _ = &x[9] // ERROR "removed.* nil check"
+ _ = &x[9] // ERROR "generated nil check"
}
func fx10() *[10]int
_ = x[9] // ERROR "generated nil check" // bug would like to remove before indirect
fx10()
- _ = x[9] // ERROR "removed nil check"
+ _ = x[9] // ERROR "generated nil check" // TODO: fix
x = fx10()
y := fx10()
- _ = &x[9] // ERROR "generated nil check"
+ _ = &x[9] // ERROR "removed[a-z ]* nil check"
y = x
_ = &x[9] // ERROR "removed[a-z ]* nil check"
x = y
- _ = &x[9] // ERROR "removed[a-z ]* nil check"
+ _ = &x[9] // ERROR "generated nil check"
}
func f5(p *float32, q *float64, r *float32, s *float64) float64 {