[Bug target/83208] [arm-linux-gnueabi-gcc] wrong code at optimization level -O2 and -O3 for union assignment

[ktkachov at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83208

--- Comment #3 from ktkachov at gcc dot gnu.org ---
The testcase is "fixed" by using -fno-strict-aliasing.
In this example pointers c and d alias each other, they are of incompatible
types and they are both dereferenced, so the testcase has undefined behaviour.