[Bug tree-optimization/88896] [8/9 Regression] integer overflow check optimized away

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88896

--- Comment #4 from Jakub Jelinek  ---
The compiler optimizes the program with the assumption that undefined behavior
doesn't happen.  So, e.g. it can remove loop condition if it proves that
undefined behavior happens before the last iteration and many other
possibilities.
Use -fsanitize=undefined to discover the UB if unsure (though that doesn't
catch e.g. aliasing bugs).

[Bug tree-optimization/88896] [8/9 Regression] integer overflow check optimized away

[daniel.f.starke at freenet dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88896

--- Comment #3 from Daniel Starke  ---
Never mind my question.

[Bug tree-optimization/88896] [8/9 Regression] integer overflow check optimized away

[daniel.f.starke at freenet dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88896

--- Comment #2 from Daniel Starke  ---
You are right. So you are saying that the compiler actually checks all cases of
the loop?

[Bug tree-optimization/88896] [8/9 Regression] integer overflow check optimized away

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88896

Jakub Jelinek  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 CC||jakub at gcc dot gnu.org
 Resolution|--- |INVALID

--- Comment #1 from Jakub Jelinek  ---
Started with r251141, but it seems your testcase is invalid:
test.c:72:101: runtime error: signed integer overflow: 35792640 * 60 cannot be
represented in type 'int'
Guess you want to e.g. change * 365 to * 365U or * (uint32_t) 365, so that all
the arithmetics is done in uint32_t type when you want to support up to
uint32_t max.