From 0156b797e6f0d1a116a19cd852f569ec2c2eec11 Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 27 Oct 2022 08:28:06 -0700 Subject: cmd/compile: recognize when the result of append has a constant length Fixes a performance regression due to CL 418554. Fixes #56440 Change-Id: I6ff152e9b83084756363f49ee6b0844a7a284880 Reviewed-on: https://go-review.googlesource.com/c/go/+/445875 Run-TryBot: Keith Randall Reviewed-by: Keith Randall TryBot-Result: Gopher Robot Reviewed-by: Cherry Mui --- test/codegen/issue56440.go | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 test/codegen/issue56440.go (limited to 'test/codegen') diff --git a/test/codegen/issue56440.go b/test/codegen/issue56440.go new file mode 100644 index 0000000000..36b52ace03 --- /dev/null +++ b/test/codegen/issue56440.go @@ -0,0 +1,18 @@ +// asmcheck + +// Copyright 2022 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. + +// Check to make sure that we recognize when the length of an append +// is constant. We check this by making sure that the constant length +// is folded into a load offset. + +package p + +func f(x []int) int { + s := make([]int, 3) + s = append(s, 4, 5) + // amd64:`MOVQ\t40\(.*\),` + return x[len(s)] +} -- cgit v1.3