https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112787
--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #8) > (In reply to Eric Botcazou from comment #7) > > This has introduced regressions on the 12 and 13 branches for x86-64/Linux: > > > > FAIL: g++.dg/opt/pr91838.C -std=c++14 scan-assembler > > pxor\\\\s+%xmm0,\\\\s+%xmm0 > > FAIL: g++.dg/opt/pr91838.C -std=c++17 scan-assembler > > pxor\\\\s+%xmm0,\\\\s+%xmm0 > > FAIL: g++.dg/opt/pr91838.C -std=c++20 scan-assembler > > pxor\\\\s+%xmm0,\\\\s+%xmm0 > > > > https://gcc.gnu.org/pipermail/gcc-testresults/2024-March/809244.html > > The IR looks like: > _4 = BIT_FIELD_REF <x_1(D), 16, 0>; > _5 = _4 >> 8; > > Well that is "undefined" in the IR. > That requires r14-2821-gd1c072a1c3411a6fe29900750b38210af8451eeb and > r14-2985-g04aa0edcace22a to be backported too. > I guess this testcase should just be xfailed on the GCC 13 and 12 branches > even. Also note bug 91838 comment #17 specifically talks about this could happen even.
