1 // compile 2 3 // Copyright 2017 The Go Authors. All rights reserved. 4 // Use of this source code is governed by a BSD-style 5 // license that can be found in the LICENSE file. 6 7 // Make sure assembly offsets don't get too large. 8 9 // To trigger issue21655, the index offset needs to be small 10 // enough to fit into an int32 (to get rewritten to an ADDQconst) 11 // but large enough to overflow an int32 after multiplying by the stride. 12 13 package main 14 15 func f1(a []int64, i int64) int64 { 16 return a[i+1<<30] 17 } 18 func f2(a []int32, i int64) int32 { 19 return a[i+1<<30] 20 } 21 func f3(a []int16, i int64) int16 { 22 return a[i+1<<30] 23 } 24 func f4(a []int8, i int64) int8 { 25 return a[i+1<<31] 26 } 27 func f5(a []float64, i int64) float64 { 28 return a[i+1<<30] 29 } 30 func f6(a []float32, i int64) float32 { 31 return a[i+1<<30] 32 } 33 34 // Note: Before the fix for issue 21655, f{1,2,5,6} made 35 // the compiler crash. f3 silently generated the wrong 36 // code, using an offset of -1<<31 instead of 1<<31. 37 // (This is due to the assembler accepting offsets 38 // like 0x80000000 and silently using them as 39 // signed 32 bit offsets.) 40 // f4 was ok, but testing it can't hurt. 41 42 func f7(ss []*string, i int) string { 43 const offset = 3 << 29 // 3<<29 * 4 = 3<<31 = 1<<31 mod 1<<32. 44 if i > offset { 45 return *ss[i-offset] 46 } 47 return "" 48 } 49 func f8(ss []*string, i int) string { 50 const offset = 3<<29 + 10 51 if i > offset { 52 return *ss[i-offset] 53 } 54 return "" 55 } 56 func f9(ss []*string, i int) string { 57 const offset = 3<<29 - 10 58 if i > offset { 59 return *ss[i-offset] 60 } 61 return "" 62 } 63
