RFR: 8267982: enable peephole cause SIGSEGV in OopFlow::build_oop_map(Node*, int, PhaseRegAlloc*, int*)+0x238

[Vladimir Kozlov]

On Tue, 1 Jun 2021 01:25:38 GMT, SUN Guoyun <github.com+40024232+sunny868 at openjdk.org> wrote:

> Hi all,
> 
> Enable peephole can cause SIGSEGV sometimes in OopFlow::build_oop_map(Node*, int, PhaseRegAlloc*, int*)+0x238 , so must set a removed-flags for the peephole-nodes , to avoid be set-live-bit() and cause crash.
>  Please review this trivial change.
> 
> Thanks,
> Sun Guoyun

To have new flag field in base class Node is expensive (size wise). I suggest to add it to  MachNode on which peephole is executed.
 
Otherwise the fix is correct.

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Changes requested by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/4276