[PATCH] D27560: Always run GlobalDCE at O0

Chandler Carruth via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Tue Dec 13 17:45:06 PST 2016

chandlerc added a comment.

In https://reviews.llvm.org/D27560#621760, @mehdi_amini wrote:

> Another reason -O0 isn't great / enough to debug when LLVM is misbehaving is that it impacts the clang codegen (lifetime intrinsics, etc.).

But you're changing *opt*, not Clang.

I really think that we shouldn't add passes to -O0...

I am sympathetic to wanting a developer "friendly" mode in the compiler that does some cleanup by not too much so as to confuse things or slow anything down. But:

1. I don't think GlobalDCE is nearly enough.
2. I don't think it should be spelled '-O0'. I actually think this is what -O1 should be.


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