[Bug middle-end/114627] New: [14 Regression] undefined behavior in tree-profile.cc while compiling gcc.misc-tests/gcov-18.c

[Bug middle-end/114627] New: [14 Regression] undefined behavior in tree-profile.cc while compiling gcc.misc-tests/gcov-18.c

[pheeck at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114627

            Bug ID: 114627
           Summary: [14 Regression] undefined behavior in tree-profile.cc
                    while compiling gcc.misc-tests/gcov-18.c
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: testsuite-fail
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pheeck at gcc dot gnu.org
            Blocks: 63426
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Compiling gcc.misc-tests/gcov-19.c using ubsan-instrumented GCC

gcc testsuite/gcc.misc-tests/gcov-19.c -fdiagnostics-plain-output
-fcondition-coverage -ftest-coverage -lm -o ./gcov-19.exe

results in

/home/worker/buildworker/tiber-gcc-ubsan/build/gcc/tree-profile.cc:1090:48:
runtime error: shift exponent 64 is too large for 64-bit type 'long long
unsigned int'

Compiler configured with
--enable-languages=default,jit,lto,go,d --enable-host-shared
--enable-checking=release --disable-multilib
--with-build-config=bootstrap-ubsan


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63426
[Bug 63426] [meta-bug] Issues found with -fsanitize=undefined

[Bug middle-end/114627] [14 Regression] undefined behavior in tree-profile.cc while compiling gcc.misc-tests/gcov-18.c

[pheeck at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114627

Filip Kastl <pheeck at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

[Bug middle-end/114627] undefined behavior in tree-profile.cc while compiling gcc.misc-tests/gcov-18.c

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114627

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[14 Regression] undefined   |undefined behavior in
                   |behavior in tree-profile.cc |tree-profile.cc while
                   |while compiling             |compiling
                   |gcc.misc-tests/gcov-18.c    |gcc.misc-tests/gcov-18.c
   Target Milestone|14.0                        |---

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
it's not a regression from older GCC since -fcondition-coverage is new

[Bug middle-end/114627] undefined behavior in tree-profile.cc while compiling gcc.misc-tests/gcov-18.c

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114627

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by J?rgen Kvalsvik <jkv@gcc.gnu.org>:

https://gcc.gnu.org/g:a2447556a5405d2cde20afc134b90cd1d199ce04

commit r14-9864-ga2447556a5405d2cde20afc134b90cd1d199ce04
Author: Jørgen Kvalsvik <j@lambda.is>
Date:   Mon Apr 8 15:19:55 2024 +0200

    Generate constant at start of loop, without UB

    Generating the constants used for recording the edges taken for
    condition coverage would trigger undefined behavior when an expression
    had exactly 64 (== sizeof (1ULL)) conditions, as it would generate the
    constant for the next iteration at the end of the loop body, even if there
    was never a next iteration. By moving the check and constant generation
    to the top of the loop and hoisting the increment flag there is no
    opportunity for UB.

            PR middle-end/114627

    gcc/ChangeLog:

            * tree-profile.cc (instrument_decisions): Generate constant
            at the start of loop.