[PATCH v2 0/3] gimple-fold improvements
Mon Nov 15 17:33:12 GMT 2021
This patchset improves folding in cases where input lengths
and/or destination sizes may not be constant but are range bound.
Tested on x86_64 with a full bootstrap build and verified that there are
no regressions resulting from this patchset. I double-checked that the
run was current and I wasn't checking logs of a stale build.
I tested builds of bash and wpa_supplicant with this patchset.
wpa_supplicant ends up with 30 fewer __memcpy_chk calls, of which 14 are
completely optimized away and the rest transformed to __memcpy.
In bash, 3 __memcpy_chk calls are optimized away completely in addition
to a couple of memmove and strcpy chk variants being transformed into
Changes from v1:
- Use dump_* functions instead of directly using dump_file
- Bring back warnings and reduce scope of changes to strncat to only
using ranges to determine if call can be simplified to strcat.
- Renamed known_safe to known_lower
Siddhesh Poyarekar (3):
gimple-fold: Transform stp*cpy_chk to str*cpy directly
gimple-fold: Use ranges to simplify _chk calls
gimple-fold: Use ranges to simplify strncat and snprintf
gcc/gimple-fold.c | 343 ++++++++++--------------
gcc/testsuite/gcc.dg/Wobjsize-1.c | 5 +-
gcc/testsuite/gcc.dg/fold-stringops-1.c | 23 ++
gcc/testsuite/gcc.dg/fold-stringops-2.c | 63 +++++
gcc/testsuite/gcc.dg/fold-stringops-3.c | 18 ++
5 files changed, 256 insertions(+), 196 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/fold-stringops-1.c
create mode 100644 gcc/testsuite/gcc.dg/fold-stringops-2.c
create mode 100644 gcc/testsuite/gcc.dg/fold-stringops-3.c
More information about the Gcc-patches