go/test/prove_popcount.go

38 lines
1.0 KiB
Go

// errorcheck -0 -d=ssa/prove/debug=1
//go:build amd64.v3 || arm64
// Copyright 2025 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.
// FIXME(@Jorropo): this file exists because I havn't yet bothered to
// make prove work on the pure go function call fallback.
// My idea was to wait until CL 637936 is merged, then we can always emit
// the PopCount SSA operation and translate them to pure function calls
// in late-opt.
package main
import "math/bits"
func onesCountsBounds(x uint64, ensureAllBranchesCouldHappen func() bool) int {
z := bits.OnesCount64(x)
if ensureAllBranchesCouldHappen() && z > 64 { // ERROR "Disproved Less64$"
return 42
}
if ensureAllBranchesCouldHappen() && z <= 64 { // ERROR "Proved Leq64$"
return 4242
}
if ensureAllBranchesCouldHappen() && z < 0 { // ERROR "Disproved Less64$"
return 424242
}
if ensureAllBranchesCouldHappen() && z >= 0 { // ERROR "Proved Leq64$"
return 42424242
}
return z
}
func main() {
}