https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88760
--- Comment #9 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 15 Jan 2019, ktkachov at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88760 > > --- Comment #8 from ktkachov at gcc dot gnu.org --- > btw looks likes ICC vectorises this as well as unrolling: > ..B1.14: > movl (%rcx,%rbx,4), %r15d > vmovsd (%rdi,%r15,8), %xmm2 > movl 4(%rcx,%rbx,4), %r15d > vmovhpd (%rdi,%r15,8), %xmm2, %xmm3 > movl 8(%rcx,%rbx,4), %r15d > vfmadd231pd (%r10,%rbx,8), %xmm3, %xmm0 > vmovsd (%rdi,%r15,8), %xmm4 > movl 12(%rcx,%rbx,4), %r15d > vmovhpd (%rdi,%r15,8), %xmm4, %xmm5 > movl 16(%rcx,%rbx,4), %r15d > vfmadd231pd 16(%r10,%rbx,8), %xmm5, %xmm1 > vmovsd (%rdi,%r15,8), %xmm6 > movl 20(%rcx,%rbx,4), %r15d > vmovhpd (%rdi,%r15,8), %xmm6, %xmm7 > movl 24(%rcx,%rbx,4), %r15d > vfmadd231pd 32(%r10,%rbx,8), %xmm7, %xmm0 > vmovsd (%rdi,%r15,8), %xmm8 > movl 28(%rcx,%rbx,4), %r15d > vmovhpd (%rdi,%r15,8), %xmm8, %xmm9 > vfmadd231pd 48(%r10,%rbx,8), %xmm9, %xmm1 > addq $8, %rbx > cmpq %r14, %rbx > jb ..B1.14 > > Is that something GCC could reasonably do? GCC could choose a larger vectorization factor, yes. The longer epilogue could be vectorized with the same vector size again then.
