On Fri, 20 Mar 2020 at 16:19, Richard Henderson <richard.hender...@linaro.org> wrote: > > On 3/20/20 9:04 AM, Philippe Mathieu-Daudé wrote: > > Not related to this patch, but this line generates a warning with Clang: > > > > CC rx-softmmu/target/rx/cpu.o > > target/rx/cpu.c:158:33: warning: The result of the left shift is undefined > > because the left operand is negative > > address = physical = addr & TARGET_PAGE_MASK; > > ^~~~~~~~~~~~~~~~ > > include/exec/cpu-all.h:234:45: note: expanded from macro 'TARGET_PAGE_MASK' > > #define TARGET_PAGE_MASK ((target_long)-1 << TARGET_PAGE_BITS) > > ~~~~~~~~~~~~~~~ ^ > > 1 warning generated. > > >From configure: > > > # We use -fwrapv to tell the compiler that we require a C dialect where > > # left shift of signed integers is well defined and has the expected > > # 2s-complement style results. (Both clang and gcc agree that it > > # provides these semantics.) > > Clang is *supposed* to be not generating those warnings.
I do have clang in my build tests, so at least some versions of clang do indeed correctly handle -fwrapv. What version are you using, Philippe ? thanks -- PMM
