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Re: [PATCH] configure: disable -Wxor-used-as-pow
From: |
Eric Blake |
Subject: |
Re: [PATCH] configure: disable -Wxor-used-as-pow |
Date: |
Tue, 23 Jun 2020 13:41:15 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 |
On 6/23/20 12:37 PM, Paolo Bonzini wrote:
Clang being clang and adding more pointless warnings. In a hardware
emulator there are going to be plenty of bitwise operations, and the
chance of someone writing ^ for pow and not being caught is basically
zero.
Did this warning actually fire?
My understanding (from a quick glance of
https://reviews.llvm.org/D63423) is that it is supposed to catch
instances of '2 ^ 16' where someone meant '1 << 16' instead of 18. I
don't know if it is supposed to flag 'a ^ 16' (if it does, then it is
indeed useless), or only when both lhs and rhs are constants and where
lhs is 2 or 10, so my initial reaction is that without seeing an actual
false positive, we are premature in disabling it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
configure | 1 +
1 file changed, 1 insertion(+)
diff --git a/configure b/configure
index 8d9435a0e0..d42f060ee7 100755
--- a/configure
+++ b/configure
@@ -2062,6 +2062,7 @@ add_to nowarn_flags -Wno-string-plus-int
add_to nowarn_flags -Wno-typedef-redefinition
add_to nowarn_flags -Wno-tautological-type-limit-compare
add_to nowarn_flags -Wno-psabi
+add_to nowarn_flags -Wno-xor-used-as-pow
Pre-existing, but is it worth ordering flag additions in alphabetical
order (the three preceding lines are in the wrong order if so).
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org