From 0668e3cb1a8407547f1b4e316748d3b898564f8e Mon Sep 17 00:00:00 2001 From: Cuong Manh Le Date: Mon, 2 May 2022 00:25:16 +0700 Subject: [PATCH] cmd/compile: support pointers to arrays in arrayClear Fixes #52635 Change-Id: I85f182931e30292983ef86c55a0ab6e01282395c Reviewed-on: https://go-review.googlesource.com/c/go/+/403337 Reviewed-by: Matthew Dempsky TryBot-Result: Gopher Robot Run-TryBot: Cuong Manh Le Reviewed-by: Ian Lance Taylor --- src/cmd/compile/internal/walk/range.go | 8 +++++- test/codegen/issue52635.go | 36 ++++++++++++++++++++++++++ 2 files changed, 43 insertions(+), 1 deletion(-) create mode 100644 test/codegen/issue52635.go diff --git a/src/cmd/compile/internal/walk/range.go b/src/cmd/compile/internal/walk/range.go index dcf7a786e7..6c30fa2877 100644 --- a/src/cmd/compile/internal/walk/range.go +++ b/src/cmd/compile/internal/walk/range.go @@ -403,8 +403,14 @@ func arrayClear(loop *ir.RangeStmt, v1, v2, a ir.Node) ir.Node { return nil } lhs := stmt.X.(*ir.IndexExpr) + x := lhs.X + if a.Type().IsPtr() && a.Type().Elem().IsArray() { + if s, ok := x.(*ir.StarExpr); ok && s.Op() == ir.ODEREF { + x = s.X + } + } - if !ir.SameSafeExpr(lhs.X, a) || !ir.SameSafeExpr(lhs.Index, v1) { + if !ir.SameSafeExpr(x, a) || !ir.SameSafeExpr(lhs.Index, v1) { return nil } diff --git a/test/codegen/issue52635.go b/test/codegen/issue52635.go new file mode 100644 index 0000000000..0e4d169081 --- /dev/null +++ b/test/codegen/issue52635.go @@ -0,0 +1,36 @@ +// 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. + +// Test that optimized range memclr works with pointers to arrays. + +package codegen + +type T struct { + a *[10]int + b [10]int +} + +func (t *T) f() { + // amd64:".*runtime.memclrNoHeapPointers" + for i := range t.a { + t.a[i] = 0 + } + + // amd64:".*runtime.memclrNoHeapPointers" + for i := range *t.a { + t.a[i] = 0 + } + + // amd64:".*runtime.memclrNoHeapPointers" + for i := range t.a { + (*t.a)[i] = 0 + } + + // amd64:".*runtime.memclrNoHeapPointers" + for i := range *t.a { + (*t.a)[i] = 0 + } +} -- 2.50.0