In D146869 @arsenm pointed out that the constrained intrinsics aren't getting the strictfp attribute by default. They should be, since they are required to have it anyway.
TableGen did not know about this attribute until now. This patch adds strictfp to TableGen, and it uses it on all of the constrained intrinsics.
Eventually I think it would be better if we had some sort of fpenv access property, such that we'll know which set of target intrinsics need handling and which aspects of the fpenv