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go/test/fixedbugs/issue32454.go
Josh Bleecher Snyder b8cbcacabe cmd/compile: optimize more pointer comparisons
The existing pointer comparison optimizations
don't include pointer arithmetic. Add them.

These rules trigger a few times in std cmd, while compiling:

time.Duration.String
cmd/go/internal/tlog.NodeHash
crypto/tls.ticketKeyFromBytes (3 times)
crypto/elliptic.(*p256Point).p256ScalarMult (15 times!)
crypto/elliptic.initTable

These weird comparisons occur when using the copy builtin,
which does a pointer comparison between src and dst.

This also happens to fix #32454, by optimizing enough
early on that all values can be eliminated.

Fixes #32454

Change-Id: I799d45743350bddd15a295dc1e12f8d03c11d1c6
Reviewed-on: https://go-review.googlesource.com/c/go/+/180940
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2019-08-29 19:35:18 +00:00

24 lines
312 B
Go

// compile
// Copyright 2019 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.
package p
type T struct {
s string
f float64
}
func f() {
var f float64
var st T
for {
switch &st.f {
case &f:
f = 1
}
}
}