Consider decomposing GetElement(memory, ...) into equivalent nodes #86345
Description
One motivating example from #85871:
***** BB02
STMT00005 ( 0x021[E-] ... 0x031 )
[000025] ----------- * JTRUE void
[000024] N--------U- \--* NE int
[000022] ----------- +--* CAST double <- float
[000053] ----------- | \--* HWINTRINSIC float float GetElement
[000020] ----------- | +--* LCL_VAR simd16<System.Numerics.Vector4>(AX) V00 loc0
[000052] ----------- | \--* CNS_INT int 1
[000023] ----------- \--* CNS_DBL double 0.0000000000000000We don't get containment for the complex GetElement tree. We could if we lowered it as a LCL_FLD.
Similar (but not identical) situation exists for GetElement sources that are INDs:
// Windows x64 ABI
[MethodImpl(MethodImplOptions.NoInlining)]
private static int Problem(Vector128<float> a)
{
return (int)a.GetElement(1);
}