[Bug middle-end/115551] [missed optimization] "c1 << (a + c2)" not optimized into "(c1 << c2) << a"

[xry111 at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115551

Xi Ruoyao <xry111 at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |xry111 at gcc dot gnu.org

--- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
"c1 << (-5 + 5)" is fine but "(c1 << -5) << 5" invokes undefined behavior. 
Thus we need some range info to do this optimization.