https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115640
--- Comment #10 from Andrew Stubbs <ams at gcc dot gnu.org> --- On 26/06/2024 12:05, rguenth at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115640 > > --- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- > (In reply to Richard Biener from comment #7) >> I will have a look (and for run validation try to reproduce with gfx1036). > > OK, so with gfx1036 we end up using 16 byte vectors and the testcase > passes. The difference with gfx908 is > > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: ==> examining statement: _14 = aa[_13]; > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: vect_model_load_cost: aligned. > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: vect_model_load_cost: inside_cost = 2, prologue_cost = 0 . > > vs. > > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: ==> examining statement: _14 = aa[_13]; > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > missed: unsupported vect permute { 0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 > 10 > 10 11 11 12 12 13 13 14 14 15 15 } > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > missed: unsupported load permutation > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:19:72: > missed: not vectorized: relevant stmt not supported: _14 = aa[_13]; > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: removing SLP instance operations starting from: REALPART_EXPR > <(*hadcur_24(D))[_2]> = _86; > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > missed: unsupported SLP instances > /space/rguenther/src/gcc-autopar_devel/gcc/testsuite/gfortran.dg/vect/pr115528.f:16:12: > note: re-trying with SLP disabled > > so gfx1036 cannot do such permutes but gfx908 can? GFX10 has more limited permutation capabilities than GFX9 because it only has 32-lane vectors natively, even though we're using the 64-lane "compatibility" mode. However, in theory, the permutation capabilities on V32 and below should be the same, and some permutations on V64 are allowed, so I don't know why it doesn't use it. It's possible I broke the logic in gcn_vectorize_vec_perm_const: /* RDNA devices can only do permutations within each group of 32-lanes. Reject permutations that cross the boundary. */ if (TARGET_RDNA2_PLUS) for (unsigned int i = 0; i < nelt; i++) if (i < 31 ? perm[i] > 31 : perm[i] < 32) return false; It looks right to me though? The vec_extract patterns that also use permutations are likewise supposedly still enabled for V32 and below. Andrew
