https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80481
--- Comment #1 from Andrew Senkevich <andrew.n.senkevich at gmail dot com> --- Reload phase adds insn 1817 (1) (insn 856 855 1817 136 (set (reg:V16SI 22 xmm1 [orig:985 vect__72.36 ] [985]) (unspec:V16SI [ (mem:V16SI (plus:DI (reg/f:DI 39 r10 [orig:206 vectp.34 ] [206]) (reg:DI 2 cx [982])) [4 MEM[base: vectp.34_259, index: _972, offset: 0B]+0 S64 A32]) (reg:V16SI 47 xmm10 [1041]) ] UNSPEC_VPERMVAR)) "./test-first.c":60 4157 {avx512f_permvarv16si} (nil)) (insn 1817 856 857 136 (set (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985]) (1) (reg:V16SF 22 xmm1 [orig:985 vect__72.36 ] [985])) "./test-first.c":61 1237 {movv16sf_internal} (nil)) (insn 857 1817 858 136 (set (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985]) (fma:V16SF (neg:V16SF (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985])) (mem:V16SF (plus:DI (reg/f:DI 37 r8 [orig:201 vectp.38 ] [201]) (reg:DI 1 dx [orig:557 ivtmp.110 ] [557])) [4 MEM[base: vectp.38_249, index: ivtmp.110_977, offset: 0B]+0 S64 A512]) (reg:V16SF 28 xmm7 [orig:1034 vect_cst__243 ] [1034]))) "./test-first.c":61 1928 {*fma_fnmadd_v16sf} (nil)) and it lives until the end: #(insn:TI 856 851 1817 75 (set (reg:V16SI 22 xmm1 [orig:985 vect__72.36 ] [985]) # (unspec:V16SI [ # (mem:V16SI (plus:DI (reg/f:DI 39 r10 [orig:206 vectp.34 ] [206]) # (reg:DI 2 cx [982])) [4 MEM[base: vectp.34_259, index: _972, offset: 0B]+0 S64 A32]) # (reg:V16SI 47 xmm10 [1041]) # ] UNSPEC_VPERMVAR)) "./test-first.c":60 4157 {avx512f_permvarv16si} # (expr_list:REG_DEAD (reg:DI 2 cx [982]) # (nil))) vpermd (%r10,%rcx), %zmm10, %zmm1 # 856 avx512f_permvarv16si [length = 7] #(insn:TI 1817 856 857 75 (set (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985]) # (reg:V16SF 22 xmm1 [orig:985 vect__72.36 ] [985])) "./test-first.c":61 1237 {movv16sf_internal} # (expr_list:REG_DEAD (reg:V16SF 22 xmm1 [orig:985 vect__72.36 ] [985]) # (nil))) vmovaps %zmm1, %zmm2 # 1817 movv16sf_internal/3 [length = 6] (1) #(insn 857 1817 860 75 (set (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985]) # (fma:V16SF (neg:V16SF (reg:V16SF 23 xmm2 [orig:985 vect__72.36 ] [985])) # (mem:V16SF (plus:DI (reg/f:DI 37 r8 [orig:201 vectp.38 ] [201]) # (reg:DI 1 dx [orig:557 ivtmp.110 ] [557])) [4 MEM[base: vectp.38_249, index: ivtmp.110_977, offset: 0B]+0 S64 A512]) # (reg:V16SF 28 xmm7 [orig:1034 vect_cst__243 ] [1034]))) "./test-first.c":61 1928 {*fma_fnmadd_v16sf} # (nil)) vfnmadd132ps (%r8,%rdx), %zmm7, %zmm2 # 857 *fma_fnmadd_v16sf/1 [length = 7]