[llvm-exegeis] Computing Latency configuration upfront so we can generate many...

[llvm-exegeis] Computing Latency configuration upfront so we can generate many CodeTemplates at once.

Summary: LatencyGenerator now computes all possible mode of serial execution for an Instruction upfront and generates CodeTemplate for the ones that give the best results (e.g. no need to generate a two instructions snippet when repeating a single one would do). The next step is to generate even more configurations for cases (e.g. for XOR we should generate "XOR EAX, EAX, EAX" and "XOR EAX, EAX, EBX")

Reviewers: courbet

Reviewed By: courbet

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D53320

llvm-svn: 344689