I tried launching the Second Life viewer (Kokua 3.7.8 x64) using the latest GIT version of MESA, and noticed the viewer crashes as soon as it's time to render the world. The crash only happens when Basic Shaders are enabled. The only relevant message printed in the console appears to be:

/home/mircea/Games/SecondLife/Kokua/kokua: line 151: 14351 Segmentation fault      LD_LIBRARY_PATH="`pwd`"/lib64:"`pwd`"/lib32:"${LD_LIBRARY_PATH}" $LL_WRAPPER bin/do-not-directly-run-kokua-bin
*** Bad shutdown. ***

A GIT bisect leads to the following commit being at fault:

73dd50acf6d244979c2a657906aa56d3ac60d550 is the first bad commit
commit 73dd50acf6d244979c2a657906aa56d3ac60d550
Author: Tapani Pälli <tapani.palli@intel.com>
Date:   Wed Aug 6 09:46:54 2014 +0300

    glsl: implement switch flow control using a loop
    
    Patch removes old variable based logic for handling a break inside
    switch. Switch is put inside a loop so that existing infrastructure
    for loop flow control can be used for the switch, now also dead code
    elimination works properly.
    
    Possible 'continue' call inside a switch needs now special handling
    which is taken care of by detecting continue, breaking out and calling
    continue for the outside loop.
    
    v2: remove one unnecessary ir_expression (Curro)
    
    Fixes following Piglit tests:
    
       fs-exec-after-break.shader_test
       fs-conditional-break.shader_test
    
    No Piglit or es3conform regressions.
    
    Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
    Reviewed-by: Francisco Jerez <currojerez@riseup.net>

:040000 040000 eac8a47066723ff804317ef11bb006dd0bb80d0f b73ed6cc78a66c54d684635f69a358fd54f65929 M      src