cmd/compile: do not reuse dead value in expand_calls pass
We reuse a value for the same selector on the same arg. But if the
value is already marked dead, don't reuse it. A use of an
OpInvalid will confuse the compiler.
Fixes #48916.
Change-Id: I15b9e15b49f6e1991fe91df246cd12a193385e85
Reviewed-on: https://go-review.googlesource.com/c/go/+/355409
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/ssa/expand_calls.go b/src/cmd/compile/internal/ssa/expand_calls.go
index a0f0e65..18c9ab6 100644
--- a/src/cmd/compile/internal/ssa/expand_calls.go
+++ b/src/cmd/compile/internal/ssa/expand_calls.go
@@ -1678,7 +1678,7 @@
t := v.Type
key := selKey{v, 0, t.Size(), t}
w := x.commonArgs[key]
- if w != nil {
+ if w != nil && w.Uses != 0 { // do not reuse dead value
v.copyOf(w)
break
}
@@ -1709,9 +1709,15 @@
}
key := selKey{baseArg, offset, t.Size(), t}
w := x.commonArgs[key]
- if w != nil {
+ if w != nil && w.Uses != 0 { // do not reuse dead value
if toReplace != nil {
toReplace.copyOf(w)
+ if x.debug > 1 {
+ x.Printf("...replace %s\n", toReplace.LongString())
+ }
+ }
+ if x.debug > 1 {
+ x.Printf("-->%s\n", w.LongString())
}
return w
}
diff --git a/test/fixedbugs/issue48916.go b/test/fixedbugs/issue48916.go
new file mode 100644
index 0000000..cbe97b5
--- /dev/null
+++ b/test/fixedbugs/issue48916.go
@@ -0,0 +1,37 @@
+// compile
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Issue 48916: expand_calls pass crashes due to a (dead)
+// use of an OpInvalid value.
+
+package p
+
+type T struct {
+ num int64
+}
+
+func foo(vs map[T]struct{}, d T) error {
+ _, ok := vs[d]
+ if !ok {
+ return nil
+ }
+
+ switch d.num {
+ case 0:
+ case 1:
+ case 2:
+ case 3:
+ case 4:
+ case 5:
+ case 6:
+ var num float64
+ if num != 0 {
+ return nil
+ }
+ }
+
+ return nil
+}
