https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65701
--- Comment #7 from Jan Hubicka <hubicka at gcc dot gnu.org> --- OK, and setting --param large-function-insns=1000 gets the performance then. The key seems to be in not inlining too much into main. The hotspot change from: 1.11 �3682: mov 0x60(%rsp),%rdx 9.32 �3687:���vmovss (%rax,%r12,2),%xmm5 1.44 � � vmovss (%rax),%xmm6 4.46 � � inc %rdi 0.01 � � add $0x10,%rcx 1.17 � � vinser $0x10,(%rax,%r13,1),%xmm5,%xmm0 1.92 � � vinser $0x10,(%rax,%r12,1),%xmm6,%xmm1 0.28 � � add %r14,%rax 0.07 � � vmovlh %xmm0,%xmm1,%xmm0 2.48 � � vfmadd %xmm3,-0x10(%rcx),%xmm0,%xmm3 5.15 � � cmp %rdi,%rdx 0.01 � ���ja 3687 1.21 � vhaddp %xmm3,%xmm3,%xmm3 10.30 � mov 0x58(%rsp),%rax 0.03 � mov %r13,0x10(%rsp) 0.00 � add %rax,%rsi 1.18 � vhaddp %xmm3,%xmm3,%xmm3 10.80 � vaddss %xmm3,%xmm4,%xmm4 4.47 � cmp 0x68(%rsp),%rax (the slower variant) to: 1.38 � xor %ecx,%ecx 6.04 �17c0:���vmovss (%rax,%r11,2),%xmm3 0.18 � � mov 0x90(%rsp),%rsi 1.43 � � inc %rcx 1.42 � � vmovss (%rax),%xmm5 0.36 � � vmovss (%rdx,%rbx,2),%xmm6 2.81 � � vmovss (%rdx),%xmm7 0.90 � � vinser $0x10,(%rax,%rsi,1),%xmm3,%xmm2 2.96 � � mov 0x88(%rsp),%rsi 0.04 � � vinser $0x10,(%rax,%r11,1),%xmm5,%xmm4 2.76 � � add 0x70(%rsp),%rax 0.07 � � vinser $0x10,(%rdx,%rbx,1),%xmm7,%xmm3 0.02 � � vmovlh %xmm2,%xmm4,%xmm4 2.69 � � vinser $0x10,(%rdx,%rsi,1),%xmm6,%xmm2 1.13 � � add 0x78(%rsp),%rdx 0.04 � � vmovlh %xmm2,%xmm3,%xmm2 0.01 � � vfmadd %xmm0,%xmm2,%xmm4,%xmm0 2.74 � � cmp %rcx,0x80(%rsp) 0.07 � ���ja 17c0 1.39 � vhaddp %xmm0,%xmm0,%xmm0 4.45 � mov 0x48(%rsp),%rsi 1.42 � vhaddp %xmm0,%xmm0,%xmm0 7.96 � vaddss %xmm0,%xmm1,%xmm1 4.09 � cmp %r15,0x60(%rsp) 0.01 � � je 18b1 (the faster variant, dunno why)
