I think a lot (not all) of people will use C and C++ because they need good performance, compile time checks, portability across OS/CPU architectures and reason

I think a lot (not all) of people will use C and C++ because they need good performance, compile time checks, portability across OS/CPU architectures and reasonable memory usage. Most of the people who use C and C++ are average programmers who think their programs will do exactly what they wrote in the source code. The issue is that optimizations are required to get expected performance but some optimizations will result in programs not doing what user specified in the source code. Compiler should offer a clear split between "safe" optimizations that will not change what source code says and "unsafe" optimizations that will do their best to create fastest code. I don't use C or C++ very often and I don't know how optimizations are currently structured but if a lot of people are constantly caught unaware of what optimizations are in use and how they affect the output then this is obviously either a documentation issue or compiler interface issue - both of these are up to compiler writers to fix.