[Pixman] clang 3.0: Unsupported asm: input constraint with a matching output constraint of incompatible type!

Søren Sandmann sandmann at cs.au.dk
Wed May 30 18:33:26 PDT 2012


Jeremy Huddleston <jeremyhu at freedesktop.org> writes:

> Yes, clang-3.0 has the bug, and pixman's configure script should be detecting that and disabling the code path that tickles the bug.  In my case, config.log shows that the check is behaving correctly:
>
> configure:12684: checking whether to use MMX intrinsics
> configure:12709: /opt/local/libexec/llvm-3.0/libexec/scan-build/ccc-analyzer -c -mmmx -Winline -O0 -g3 -pipe  -fdiagnostics-show-category=name -Wall -fno-strict-aliasing -fvisibility=hidden -I/Users/jeremy/src/freedesktop/jhbuild/build/include -I/Users/jeremy/src/freedesktop/jhbuild/external/build/include conftest.c >&5
> fatal error: error in backend: Invalid operand for inline asm
> constraint 'K'!

Maybe the difference is that you are using "-O0" where Ryan is using
"-O2". The "K" constraint requires the argument to be compile-time
constant, which it is, but clang may not be able to see that without
optimization.


Soren


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