https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97249
--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
We all ready have bellow in simplify-rtx.c, it seems we can also handle such
situation here.
---
3954 case VEC_SELECT:
3955 if (!VECTOR_MODE_P (mode))
3956 {
3957 gcc_assert (VECTOR_MODE_P (GET_MODE (trueop0)));
3958 gcc_assert (mode == GET_MODE_INNER (GET_MODE (trueop0)));
3959 gcc_assert (GET_CODE (trueop1) == PARALLEL);
3960 gcc_assert (XVECLEN (trueop1, 0) == 1);
3961
3962 /* We can't reason about selections made at runtime. */
3963 if (!CONST_INT_P (XVECEXP (trueop1, 0, 0)))
3964 return 0;
3965
3966 if (vec_duplicate_p (trueop0, &elt0))
3967 return elt0;
3968
3969 if (GET_CODE (trueop0) == CONST_VECTOR)
3970 return CONST_VECTOR_ELT (trueop0, INTVAL (XVECEXP
3971 (trueop1, 0, 0)));
3972
3973 /* Extract a scalar element from a nested VEC_SELECT expression
3974 (with optional nested VEC_CONCAT expression). Some targets
3975 (i386) extract scalar element from a vector using chain of
3976 nested VEC_SELECT expressions. When input operand is a
memory
3977 operand, this operation can be simplified to a simple scalar
3978 load from an offseted memory address. */
---
