https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120196
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:748a7bc4624e7b000f6fdb93a8cf7da73ff193bb commit r16-594-g748a7bc4624e7b000f6fdb93a8cf7da73ff193bb Author: Jakub Jelinek <ja...@redhat.com> Date: Tue May 13 14:20:22 2025 +0200 libfortran: Fix up _gfortran_{,m,s}findloc2_s{1,4} [PR120196] As mentioned in the PR, _gfortran_{,m,s}findloc2_s{1,4} iterate too many times in the back case if nothing is found. For !back, the loops are for (i = 1; i <= extent; i++) so i is in the body [1, extent] if nothing is found, but for back it is for (i = extent; i >= 0; i--) so i is in the body [0, extent] and compares one element before the start of the array. Note, findloc1_s{1,4} uses for (n = len; n > 0; n--, src -= delta * len_array) for the back loop and for (n = 1; n <= len; n++, src += delta * len_array) for !back. This patch fixes that. The testcase fails under valgrind without the libgfortran changes and succeeds with those. 2025-05-13 Jakub Jelinek <ja...@redhat.com> PR libfortran/120196 * m4/ifindloc2.m4 (header1, header2): For back use i > 0 rather than i >= 0 as for condition. * generated/findloc2_s1.c: Regenerate. * generated/findloc2_s4.c: Regenerate. * gfortran.dg/pr120196.f90: New test.
