https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98167
--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> --- ;; _3 = __builtin_ia32_shufps (b_2(D), b_2(D), 0); (insn 7 6 8 (set (reg:V4SF 88) (reg/v:V4SF 86 [ b ])) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) (insn 8 7 9 (set (reg:V4SF 89) (reg/v:V4SF 86 [ b ])) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) (insn 9 8 10 (set (reg:V4SF 87) (vec_select:V4SF (vec_concat:V8SF (reg:V4SF 88) (reg:V4SF 89)) (parallel [ (const_int 0 [0]) repeated x2 (const_int 4 [0x4]) repeated x2 ]))) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) ;; _5 = __builtin_ia32_shufps (a_4(D), a_4(D), 0); (insn 11 10 12 (set (reg:V4SF 91) (reg/v:V4SF 85 [ a ])) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) (insn 12 11 13 (set (reg:V4SF 92) (reg/v:V4SF 85 [ a ])) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) (insn 13 12 14 (set (reg:V4SF 90) (vec_select:V4SF (vec_concat:V8SF (reg:V4SF 91) (reg:V4SF 92)) (parallel [ (const_int 0 [0]) repeated x2 (const_int 4 [0x4]) repeated x2 ]))) "./gcc/include/xmmintrin.h":746:19 -1 (nil)) Simplify upper to (vec_duplicate:V4SF (vec_select:SF (reg:V4SF 86) (parallel [(const_int 0)]) then add a combine splitter transform (mult:(vec_dup op1) (vec_dup op2)) to (vec_dup (mult:op1 op2)?