[X86] Prevent using X * rsqrt(X) to approximate sqrt when only sse1 is enabled.

[X86] Prevent using X * rsqrt(X) to approximate sqrt when only sse1 is enabled.

This optimization can occur after type legalization and emit a vselect with v4i32 type. But that type is not legal with sse1. This ultimately gets scalarized by the second type legalization that runs after vector op legalization, but that's really intended to handle the scalar types that might be introduced by legalizing vector ops.

For now just stop this from happening by disabling the optimization with sse1.

llvm-svn: 318965