https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119901
--- Comment #2 from Konstantinos Eleftheriou <konstantinos.eleftheriou at vrull
dot eu> ---
This is fixed by r16-905-gec5349c37afe972ee79b777ee749630b1a0a007e.
The culprit was:
(insn 23 25 22 2 (set (reg:V16HI 108)
(zero_extend:V16HI (reg:V16QI 110))) "testcase.c":8:8 discrim 1 8682
{avx2_zero_extendv16qiv16hi2}
(nil))
which is replaced now by:
(insn 23 25 22 2 (set (reg:V16HI 108)
(subreg:V16HI (reg:V16QI 110) 0)) "testcase.c":8:8 discrim 1 2403
{movv16hi_internal}
(nil))
New RTL sequence:
(insn 25 21 23 2 (set (mem/c:V16QI (symbol_ref:DI ("v") [flags 0x2] <var_decl
0x7318f2a11e40 v>) [0 MEM <char[1:32]> [(void *)&v]+0 S16 A256])
(reg:V16QI 110)) "testcase.c":8:8 discrim 1 2401 {movv16qi_internal}
(nil))
(insn 23 25 22 2 (set (reg:V16HI 108)
(subreg:V16HI (reg:V16QI 110) 0)) "testcase.c":8:8 discrim 1 2403
{movv16hi_internal}
(nil))
(insn 22 23 20 2 (set (mem/c:V16QI (const:DI (plus:DI (symbol_ref:DI ("v")
[flags 0x2] <var_decl 0x7318f2a11e40 v>)
(const_int 16 [0x10]))) [0 MEM <char[1:32]> [(void *)&v]+16
S16 A128])
(reg:V16QI 109)) "testcase.c":8:8 discrim 1 2401 {movv16qi_internal}
(nil))
(insn 20 22 26 2 (set (subreg:V16QI (reg:V16HI 108) 16)
(reg:V16QI 109)) "testcase.c":8:8 discrim 1 2401 {movv16qi_internal}
(nil))
(insn 26 20 16 2 (set (reg:V16HI 99 [ _2 ])
(reg:V16HI 108)) "testcase.c":8:8 discrim 1 2403 {movv16hi_internal}
(nil))
(insn 16 26 0 2 (set (mem:V16HI (reg/f:DI 107 [ r ]) [1 *r_5(D)+0 S32 A256])
(reg:V16HI 99 [ _2 ])) "testcase.c":8:6 discrim 1 2403
{movv16hi_internal}
(expr_list:REG_DEAD (reg/f:DI 107 [ r ])
(expr_list:REG_DEAD (reg:V16HI 99 [ _2 ])
(nil))))
Note that the additional instructions are expected, as we update the "loaded"
value using bit insertions.
