https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90122
--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Martin Sebor from comment #0) > In the test case below GCC folds the second test (as expected, on the > assumption that distinct declarations refer to distinct objects) but fails > to fold the first. > > Clang folds both (into false and true, respectively). GCC will only do that > if a and b are static or local. > > Same with extern arrays of known size. > > $ cat x.c && gcc -O2 -S -Wall -Wextra -fdump-tree-optimized=/dev/stdout > -fno-common x.c > extern int a, b; Why can't a and b point to the same address?
