[GlobalISel] LegalizerHelper: Lower (G_FSUB X, Y) to (G_FADD X, (G_FNEG Y))
[GlobalISel] LegalizerHelper: Lower (G_FSUB X, Y) to (G_FADD X, (G_FNEG Y))

Summary: No test case as none of the in-tree targets with GlobalISel support has this condition.

Reviewers: qcolombet, aditya_nandakumar, dsanders, t.p.northover, ab

Reviewed By: qcolombet

Subscribers: dberris, rovka, kristof.beyls, llvm-commits, igorb

Differential Revision: https://reviews.llvm.org/D30786

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@297512 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm