[cfe-commits] r92987 - in /cfe/trunk: include/clang/Driver/CC1Options.td include/clang/Driver/ToolChain.h lib/Driver/ToolChains.cpp lib/Driver/ToolChains.h lib/Driver/Tools.cpp lib/Frontend/CompilerInvocation.cpp test/CodeGen/libcalls.c test/Driver/ana

Chris Lattner clattner at apple.com
Fri Jan 8 16:37:57 PST 2010

On Jan 8, 2010, at 3:51 PM, Dan Gohman wrote:

> On Jan 8, 2010, at 2:15 PM, Nuno Lopes wrote:
>>> Author: djg
>>> Date: Thu Jan  7 20:20:44 2010
>>> New Revision: 92987
>>> URL: http://llvm.org/viewvc/llvm-project?rev=92987&view=rev
>>> Log:
>>> Use -fno-math-errno by default, and remove the IsMathErrnoDefault
>>> targethook, which is no longer being used. This fixes PR5971.
>> wow.. does this means that if I don't read the compiler's manual  
>> carefully and if I don't add -fmath-errno to the CFLAGS, my code  
>> will start to be silently miscompiled??
>> I don't think that giving up on correctness here is the right way  
>> to go..
> This change isn't "giving up on correctness" (unless there are bugs
> with -fno-math-errno). Code that breaks was already not entirely
> portable in this regard.
> It may be "giving up on compatibility" though. Clang is a new
> compiler, and it's a good time to get things like this right, where
> feasible. However, I'll leave it up to the clang developers to
> decide what to do.

We already have this behavior in llvm-gcc, so I think it is definitely  
the right thing for Clang.


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