[WebAssembly] Bail out of fastisel earlier when computing PIC addresses
[WebAssembly] Bail out of fastisel earlier when computing PIC addresses

This change partially reverts https://reviews.llvm.org/D54647 in favor
of bailing out during computeAddress instead.

This catches the condition earlier and handles more cases.

Differential Revision: https://reviews.llvm.org/D60986

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@358948 91177308-0d34-0410-b5e6-96231b3b80d8

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