cmd/compile: compiler hangs on tiny program
ALTree opened this issue · 5 comments
ALTree commented
$ gotip version
go version devel +d11df8baa8 Sun Apr 22 22:32:11 2018 +0000 linux/amd64
The following program:
package p
func spin() {
var i int
var b bool
switch 1 {
case 0:
i = 1
}
switch 1 {
case i:
default:
i = 1
b = !b && (b && !b) && b
}
switch false {
case false:
i = 3 + -i
switch 0 {
case 1 - i:
}
}
}hangs the tip compiler (spinning at 100% cpu) when built for amd64.
It compiles in no time in go1.10.
ALTree commented
The issue was introduced in CL 100935 (cmd/compile: implement CMOV on amd64).
cc @rasky @randall77
TocarIP commented
Looks like an endless loop in rules application. Will send fix soon
gopherbot commented
Change https://golang.org/cl/108879 mentions this issue: cmd/compile/internal/ssa: fix endless compile loop on AMD64
TocarIP commented
Looks like it is easy to introduce endless rewrite, maybe we should just stop rewrite after e. g. 1000*values rewrites and suggest opening a bug.