[clang] [clang] Allow `ConditionalOperator` fast-math flags to be overridden by `pragma float_control` (PR #105912)

[John McCall via cfe-commits]

rjmccall wrote:

I don't understand what fast-math flags are supposed to mean for loads, phis, and selects.  These are not arithmetic operations; they just propagate values.  If you're trying to implement some kind of rule where fast-math analysis should not pass across certain kinds of abstraction, you need to be holistically designing the IR around that, not gradually accreting flags onto every opaque data instruction.

https://github.com/llvm/llvm-project/pull/105912