https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90883
--- Comment #5 from rguenther at suse dot de <rguenther at suse dot de> --- On June 14, 2019 2:27:22 PM GMT+02:00, "jamborm at gcc dot gnu.org" <gcc-bugzi...@gcc.gnu.org> wrote: >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90883 > >--- Comment #4 from Martin Jambor <jamborm at gcc dot gnu.org> --- >(In reply to Richard Biener from comment #3) >> ...I also wonder why SRA does not elide the aggregate copy. > >SRA has a special condition not to attempt to totally scalarize array >of chars, so that it does not interfere with bigger types >placement-new placed in those. > >It is true that artificially removing this condition would avoid the >problem though. However, the IL after esra would look like the >following: > <bb 2> : > SR.1_3 = 0; > SR.2_8 = 0; > SR.3_9 = 0; > SR.4_10 = 0; > SR.5_11 = 0; > SR.6_12 = 0; > SR.7_13 = 0; > SR.8_14 = 0; > SR.1_15 = 0; > SR.2_16 = 0; > SR.3_17 = 0; > SR.4_18 = 0; > SR.5_19 = 0; > SR.6_20 = 0; > SR.7_21 = 0; > SR.8_22 = 0; > D.10899.a._M_elems[0] = SR.1_15; > D.10899.a._M_elems[1] = SR.2_16; > D.10899.a._M_elems[2] = SR.3_17; > D.10899.a._M_elems[3] = SR.4_18; > D.10899.a._M_elems[4] = SR.5_19; > D.10899.a._M_elems[5] = SR.6_20; > D.10899.a._M_elems[6] = SR.7_21; Ick. OK, so the important fact would be the zero initialization which we'd only see in a flow sensitive analysis? Then the above could just be D. 10899.a._M_elems = {}; > D.10899.b = SR.8_22; > return D.10899;
