Superfluous instructions when using `_mm_set_ss` with `-ffp-model=strict` on `x86_64`

[jerryct]

When using the intrinics _mm_set_ss with -ffp-model=strict compiler flag
Clang generates two seemingly unrelated instructions (neither eax nor xmm1 are used by andps)

        xor     eax, eax
        cvtsi2ss        xmm1, eax
        andps   xmm0, xmmword ptr [rip + .LCPI1_0]

reproducer: https://godbolt.org/z/3fj6ob345

For example when switching to _mm_load_ps1 instead the instructions
are not generated: https://godbolt.org/z/8G6vGEjxE

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: Jerry Crunchtime (jerryct)

When using the intrinics `_mm_set_ss` with `-ffp-model=strict` compiler flag Clang generates two seemingly unrelated instructions (neither `eax` nor `xmm1` are used by `andps`)

        xor     eax, eax
        cvtsi2ss        xmm1, eax
        andps   xmm0, xmmword ptr [rip + .LCPI1_0]

reproducer: https://godbolt.org/z/3fj6ob345

For example when switching to _mm_load_ps1 instead the instructions
are not generated: https://godbolt.org/z/8G6vGEjxE

[RKSimon]

/cherry-pick 3b49d27 6dcce42