[llvm-exegesis] Improve Register Setup (roll forward of D51856).

Summary:
Added function to set a register to a particular value + tests.
Add EFLAGS test, use new setRegTo instead of setRegToConstant.

Reviewers: courbet, javed.absar

Subscribers: llvm-commits, tschuett, mgorny

Differential Revision: https://reviews.llvm.org/D52297

llvm-svn: 342644
diff --git a/llvm/tools/llvm-exegesis/lib/Target.cpp b/llvm/tools/llvm-exegesis/lib/Target.cpp
index b45c821..8baa849 100644
--- a/llvm/tools/llvm-exegesis/lib/Target.cpp
+++ b/llvm/tools/llvm-exegesis/lib/Target.cpp
@@ -89,27 +89,9 @@
 // Default implementation.
 class ExegesisDefaultTarget : public ExegesisTarget {
 private:
-  std::vector<llvm::MCInst> setRegToConstant(const llvm::MCSubtargetInfo &STI,
-                                             unsigned Reg) const override {
-    llvm_unreachable("Not yet implemented");
-  }
-
   std::vector<llvm::MCInst> setRegTo(const llvm::MCSubtargetInfo &STI,
-                                     const llvm::APInt &Value,
-                                     unsigned Reg) const override {
-    llvm_unreachable("Not yet implemented");
-  }
-
-  unsigned getScratchMemoryRegister(const llvm::Triple &) const override {
-    llvm_unreachable("Not yet implemented");
-  }
-
-  void fillMemoryOperands(InstructionBuilder &IB, unsigned Reg,
-                          unsigned Offset) const override {
-    llvm_unreachable("Not yet implemented");
-  }
-
-  unsigned getMaxMemoryAccessSize() const override {
+                                     unsigned Reg,
+                                     const llvm::APInt &Value) const override {
     llvm_unreachable("Not yet implemented");
   }