https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105070
Bug ID: 105070 Summary: Missing debug info for switch statement Product: gcc Version: 11.1.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: debug Assignee: unassigned at gcc dot gnu.org Reporter: liyd2021 at gmail dot com Target Milestone: --- Affected versions: gcc 11.1.0, since gcc 9 (terminal) $ gcc-9 -v Using built-in specs. COLLECT_GCC=gcc-9 COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper OFFLOAD_TARGET_NAMES=nvptx-none:hsa OFFLOAD_TARGET_DEFAULT=1 Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.4.0-1ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-9 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-9-yTrUTS/gcc-9-9.4.0/debian/tmp-nvptx/usr,hsa --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 9.4.0 (Ubuntu 9.4.0-1ubuntu1~20.04) Debugging the following program will directly hit "return 1" instead of the "switch (x)" in this specific case. Did not observe this problem on other switch-cases. (terminal) $ cat a.c && gcc -g -OO a.c extern void abort(void); int foo(int x) { switch (x) { case 1: case 3: case 5: return 1; default: return 0; } } int main() { int i, r; for (i = 0; i < 6; i++) { r = foo(i); if(i == 1 || i == 3 || i == 5){ if(r == 0){ abort(); } } } return 0; } -------------------- (terminal) $ gdb a.out (gdb) b foo Breakpoint 1 at 0x4011b3: file a.c, line 8. (gdb) r Breakpoint 1, foo (x=1) at a.c:8 8 return 1; (gdb) c Continuing. Breakpoint 1, foo (x=3) at a.c:8 8 return 1; (gdb) c Continuing. Breakpoint 1, foo (x=5) at a.c:8 8 return 1; This bug seemed to be missing debug_line. (terminal) $ readelf --debug-dump=decodedline a.out Contents of the .debug_line section: CU: a.c: File Line Starting address View Stmt a.c 3 0x401185 x a.c 8 0x4011b3 x <-- line 4 is missing a.c 10 0x4011ba x a.c 12 0x4011bf x a.c 14 0x4011c1 x