From: Matthew Dempsky <mdempsky@google.com>
Date: Thu, 17 Aug 2023 05:37:42 +0000 (-0700)
Subject: cmd/compile/internal/typecheck: push ONEW into go/defer wrappers
X-Git-Tag: go1.22rc1~1233
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=2c51ea11b0f96ece871f84f83fb393ff80ec8f4a;p=gostls13.git

cmd/compile/internal/typecheck: push ONEW into go/defer wrappers

Currently, we rewrite:

	go f(new(T))

into:

	tmp := new(T)
	go func() { f(tmp) }()

However, we can both shrink the closure and improve escape analysis by
instead rewriting it into:

	go func() { f(new(T)) }()

This CL does that.

Change-Id: Iae16a476368da35123052ca9ff41c49159980458
Reviewed-on: https://go-review.googlesource.com/c/go/+/520340
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Auto-Submit: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
---

diff --git a/src/cmd/compile/internal/typecheck/stmt.go b/src/cmd/compile/internal/typecheck/stmt.go
index 4c21f045af..93a147c335 100644
--- a/src/cmd/compile/internal/typecheck/stmt.go
+++ b/src/cmd/compile/internal/typecheck/stmt.go
@@ -241,7 +241,7 @@ func tcGoDefer(n *ir.GoDeferStmt) {
 		// the wrapper, so we don't need to allocate space for them within
 		// the closure.
 		switch arg.Op() {
-		case ir.OLITERAL, ir.ONIL, ir.OMETHEXPR:
+		case ir.OLITERAL, ir.ONIL, ir.OMETHEXPR, ir.ONEW:
 			return
 		case ir.ONAME:
 			arg := arg.(*ir.Name)
diff --git a/test/fixedbugs/issue31573.go b/test/fixedbugs/issue31573.go
index a0cff3099a..5197163f04 100644
--- a/test/fixedbugs/issue31573.go
+++ b/test/fixedbugs/issue31573.go
@@ -19,31 +19,31 @@ func g() {
 	defer f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
 
 	go f()
-	go f(new(int))           // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
-	go f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
+	go f(new(int))           // ERROR "... argument does not escape$" "new\(int\) does not escape$"
+	go f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) does not escape$"
 
 	go f(nil...)
 	go f([]*int{}...)                   // ERROR "\[\]\*int{} does not escape$"
-	go f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
-	go f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
+	go f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
+	go f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
 
 	for {
 		defer f()
-		defer f(new(int))           // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
-		defer f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
+		defer f(new(int))           // ERROR "... argument does not escape$" "new\(int\) does not escape$"
+		defer f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) does not escape$"
 
 		defer f(nil...)
 		defer f([]*int{}...)                   // ERROR "\[\]\*int{} does not escape$"
-		defer f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
-		defer f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
+		defer f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
+		defer f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
 
 		go f()
-		go f(new(int))           // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
-		go f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) escapes to heap$"
+		go f(new(int))           // ERROR "... argument does not escape$" "new\(int\) does not escape$"
+		go f(new(int), new(int)) // ERROR "... argument does not escape$" "new\(int\) does not escape$"
 
 		go f(nil...)
 		go f([]*int{}...)                   // ERROR "\[\]\*int{} does not escape$"
-		go f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
-		go f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) escapes to heap$"
+		go f([]*int{new(int)}...)           // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
+		go f([]*int{new(int), new(int)}...) // ERROR "\[\]\*int{...} does not escape$" "new\(int\) does not escape$"
 	}
 }