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40 lines
845 B
Go
40 lines
845 B
Go
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// run
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// Copyright 2020 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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// Checks that conversion of CMP(x,-y) -> CMN(x,y) is only applied in correct context.
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package main
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type decimal struct {
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d [8]byte // digits, big-endian representation
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dp int // decimal point
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}
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var powtab = []int{1, 3, 6, 9, 13, 16, 19, 23, 26}
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//go:noinline
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func foo(d *decimal) int {
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exp := int(d.d[1])
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if d.dp < 0 || d.dp == 0 && d.d[0] < '5' {
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var n int
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if -d.dp >= len(powtab) {
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n = 27
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} else {
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n = powtab[-d.dp] // incorrect CMP -> CMN substitution causes indexing panic.
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}
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exp += n
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}
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return exp
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}
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func main() {
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var d decimal
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d.d[0] = '1'
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if foo(&d) != 1 {
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println("FAILURE (though not the one this test was written to catch)")
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}
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}
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