[PATCH PR96053] Add "#pragma GCC no_reduc_chain"

[zhoukaipeng (A)]

Hi,

It is the patch to add "#pragma GCC no_reduc_chain" for pr96053.  It only 
completes the front end of C language.

For the testcase, it successfully skipped doing slp by finding sequences from 
reduction chains.  Without "#pragma GCC no_reduc_chain", it will fail to do 
vectorization.

Please help to check if there is any problem.  If there is no problem, I will 
continue to complete the front end of the remaining languages.

Thanks,
Kaipeng Zhou

add-pragma-v1.diff
Description: add-pragma-v1.diff