https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106989
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- /app/example.cpp:20:25: note: Detected interleaving store a[i_27] and a[i_27] /app/example.cpp:20:25: note: Queuing group with duplicate access for fixup /app/example.cpp:20:25: note: zero step in outer loop. /app/example.cpp:20:25: note: zero step in outer loop. /app/example.cpp:20:25: missed: not vectorized: complicated access pattern. /app/example.cpp:22:18: missed: not vectorized: complicated access pattern. /app/example.cpp:20:25: missed: bad data access. ... /app/example.cpp:21:27: note: dependence distance = 0. /app/example.cpp:21:27: note: dependence distance == 0 between b[i_27] and b[i_27] /app/example.cpp:21:27: note: dependence distance = 1. /app/example.cpp:22:18: missed: not vectorized, possible dependence between data-refs a[i_27] and a[_9] /app/example.cpp:21:27: missed: bad data dependence. /app/example.cpp:21:27: note: ***** Analysis failed with vector mode V4SF There is a missing DSE before hand: # VUSE <.MEM_28> _1 = bD.3768[i_27]; # VUSE <.MEM_28> _2 = cD.3769[i_27]; # VUSE <.MEM_28> _3 = dD.3770[i_27]; _4 = _2 * _3; _5 = _1 + _4; # .MEM_19 = VDEF <.MEM_28> aD.3767[i_27] = _5; # VUSE <.MEM_19> _6 = eD.3771[i_27]; _7 = _3 * _6; _8 = _5 + _7; # .MEM_20 = VDEF <.MEM_19> bD.3768[i_27] = _8; # RANGE [irange] int [1, 31999] NONZERO 0x7fff _9 = i_27 + 1; # VUSE <.MEM_20> _10 = aD.3767[_9]; _11 = _3 * _10; _12 = _8 + _11; # .MEM_21 = VDEF <.MEM_20> aD.3767[i_27] = _12; DSE does not notice the store defining MEM_19 does touch the load: # VUSE <.MEM_20> _10 = aD.3767[_9]; And that it is redudent with the store defining MEM_21.
