cmd/compile: ignore contentEscapes for marking nodes as escaping

We can still stack allocate and VarKill nodes which don't
escape but their content does.

Fixes #16996

Change-Id: If8aa0fcf2c327b4cb880a3d5af8d213289e6f6bf
Reviewed-on: https://go-review.googlesource.com/28575
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

diff --git a/src/cmd/compile/internal/gc/esc.go b/src/cmd/compile/internal/gc/esc.go
index c5597d7f487ebefb61587f289bb87683e9b5d249..0fd514fbaf49e5d1c0219a8afd42f521ba9befd5 100644 (file)
--- a/src/cmd/compile/internal/gc/esc.go
+++ b/src/cmd/compile/internal/gc/esc.go
@@ -1572,7 +1572,7 @@ func esccall(e *EscState, n *Node, up *Node) {
                }
 
                if haspointers(t.Type) {
-                       if escassignfromtag(e, note, nE.Escretval, src) == EscNone && up.Op != ODEFER && up.Op != OPROC {
+                       if escassignfromtag(e, note, nE.Escretval, src)&EscMask == EscNone && up.Op != ODEFER && up.Op != OPROC {
                                a := src
                                for a.Op == OCONVNOP {
                                        a = a.Left

diff --git a/test/live.go b/test/live.go
index db47e14e93c2a4d8cd5e6940b347c9f32e484e76..ef0ade23c71d27615bd4b185834603a13539aad6 100644 (file)
--- a/test/live.go
+++ b/test/live.go
@@ -643,3 +643,13 @@ func good40() {
        printnl() // ERROR "live at call to printnl: autotmp_[0-9]+ ret$"
        _ = t
 }
+
+func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$"
+       ddd2(x, y) // ERROR "live at call to ddd2: autotmp_[0-9]+$"
+       printnl()  // nothing live here.  See issue 16996.
+}
+func ddd2(a ...*int) { // ERROR "live at entry to ddd2: a$"
+       sink = a[0]
+}
+
+var sink *int

diff --git a/test/live_ssa.go b/test/live_ssa.go
index 27c4528dc1b022c81c3eeeae4ea4518bacc804ab..cf06141b44f4f741beb09b7c7e8adc32fde1e1b9 100644 (file)
--- a/test/live_ssa.go
+++ b/test/live_ssa.go
@@ -646,3 +646,11 @@ func good40() {
        printnl() // ERROR "live at call to printnl: autotmp_[0-9]+ ret$"
        _ = t
 }
+
+func ddd1(x, y *int) { // ERROR "live at entry to ddd1: x y$"
+       ddd2(x, y) // ERROR "live at call to ddd2: autotmp_[0-9]+$"
+       printnl()  // nothing live here.  See issue 16996.
+}
+func ddd2(a ...*int) { // ERROR "live at entry to ddd2: a$"
+       sink = a[0]
+}