| // run |
| |
| // Copyright 2026 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. |
| |
| // Issue 79182: SHLQconst/SHLLconst rewrite rule for (x+x)<<c |
| // missed a bounds check on c, causing c+1 to overflow the valid |
| // shift range and producing incorrect results on amd64. |
| |
| package main |
| |
| //go:noinline |
| func shl32(x uint32) uint32 { |
| return (x + x) << 31 |
| } |
| |
| //go:noinline |
| func shl64(x uint64) uint64 { |
| return (x + x) << 63 |
| } |
| |
| func main() { |
| if got := shl32(1); got != 0 { |
| println("shl32(1) =", got, "want 0") |
| panic("FAIL") |
| } |
| if got := shl64(1); got != 0 { |
| println("shl64(1) =", got, "want 0") |
| panic("FAIL") |
| } |
| } |
