[Bug tree-optimization/52574] [4.6 Regression] gcc tree optimizer generates incorrect vector load instructions for x86_64, app crashes

[deepak.ravi at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52574

Deepak Ravi <deepak.ravi at gmail dot com> changed:

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--- Comment #2 from Deepak Ravi <deepak.ravi at gmail dot com> 2012-03-13 19:18:45 UTC ---
(In reply to comment #1)
> The testcase is invalid C, while x86_64/i?86 will do the expected thing of
> doing unaligned loads/stores silently, it won't do that in vectorized code or
> for atomic accesses. 

Shouldn't the compiler vectorize the code _conservatively_, by generating code
to check if the address is aligned or generating unaligned vector load
instructions, as any code written for x86_64 will break with -O3, with newer
gcc. 

Also note that, this bug will get triggered only when __restricted is used. If
you remove __restricted, gcc is generating proper code. Also it works properly
for gcc 4.7 too (even with __restricted).