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https://github.com/golang/go
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9f291d1fc3
Unlike normal load+op opcodes, the load+compare opcode does not clobber its non-load argument. Allow the load+compare merge to happen even if the non-load argument is used elsewhere. Noticed when investigating issue #28417. Change-Id: Ibc48d1f2e06ae76034c59f453815d263e8ec7288 Reviewed-on: https://go-review.googlesource.com/c/145097 Reviewed-by: Ainar Garipov <gugl.zadolbal@gmail.com> Reviewed-by: Ben Shi <powerman1st@163.com>
96 lines
1.4 KiB
Go
96 lines
1.4 KiB
Go
// asmcheck
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// Copyright 2018 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package codegen
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var x [2]bool
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var x8 [2]uint8
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var x16 [2]uint16
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var x32 [2]uint32
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var x64 [2]uint64
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func compMem1() int {
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// amd64:`CMPB\t"".x\+1\(SB\), [$]0`
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if x[1] {
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return 1
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}
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// amd64:`CMPB\t"".x8\+1\(SB\), [$]7`
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if x8[1] == 7 {
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return 1
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}
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// amd64:`CMPW\t"".x16\+2\(SB\), [$]7`
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if x16[1] == 7 {
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return 1
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}
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// amd64:`CMPL\t"".x32\+4\(SB\), [$]7`
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if x32[1] == 7 {
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return 1
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}
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// amd64:`CMPQ\t"".x64\+8\(SB\), [$]7`
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if x64[1] == 7 {
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return 1
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}
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return 0
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}
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//go:noinline
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func f(x int) bool {
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return false
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}
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//go:noinline
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func f8(x int) int8 {
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return 0
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}
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//go:noinline
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func f16(x int) int16 {
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return 0
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}
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//go:noinline
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func f32(x int) int32 {
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return 0
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}
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//go:noinline
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func f64(x int) int64 {
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return 0
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}
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func compMem2() int {
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// amd64:`CMPB\t8\(SP\), [$]0`
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if f(3) {
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return 1
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}
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// amd64:`CMPB\t8\(SP\), [$]7`
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if f8(3) == 7 {
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return 1
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}
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// amd64:`CMPW\t8\(SP\), [$]7`
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if f16(3) == 7 {
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return 1
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}
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// amd64:`CMPL\t8\(SP\), [$]7`
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if f32(3) == 7 {
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return 1
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}
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// amd64:`CMPQ\t8\(SP\), [$]7`
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if f64(3) == 7 {
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return 1
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}
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return 0
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}
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func compMem3(x, y *int) (int, bool) {
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// We can do comparisons of a register with memory even if
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// the register is used subsequently.
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r := *x
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// amd64:`CMPQ\t\(`
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// 386:`CMPL\t\(`
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return r, r < *y
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}
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