[RISCV] Add RISCV-specific TargetTransformInfo

Summary:
LLVM Allows Targets to provide information that guides optimisations
made to LLVM IR. This is done with callbacks on a TargetTransformInfo object.

This patch adds a TargetTransformInfo class for RISC-V. This will allow us to
implement RISC-V specific callbacks as they become necessary.

This commit also adds the getIntImmCost callbacks, and tests them with a simple
constant hoisting test. Our immediate costs are on the conservative side, for
the moment, but we prevent hoisting in most circumstances anyway.

Previous review was on D63007

Reviewers: asb, luismarques

Reviewed By: asb

Subscribers: ributzka, MaskRay, llvm-commits, Jim, benna, psnobl, jocewei, PkmX, rkruppe, the_o, brucehoult, MartinMosbeck, rogfer01, edward-jones, zzheng, jrtc27, shiva0217, kito-cheng, niosHD, sabuasal, apazos, simoncook, johnrusso, rbar, hiraditya, mgorny

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63433

llvm-svn: 364046

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index d539dbeef23..f4e6ed9f628 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -10,11 +10,13 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "RISCV.h"
 #include "RISCVTargetMachine.h"
+#include "RISCV.h"
 #include "RISCVTargetObjectFile.h"
+#include "RISCVTargetTransformInfo.h"
 #include "TargetInfo/RISCVTargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
@@ -61,6 +63,11 @@ RISCVTargetMachine::RISCVTargetMachine(const Target &T, const Triple &TT,
   initAsmInfo();
 }
 
+TargetTransformInfo
+RISCVTargetMachine::getTargetTransformInfo(const Function &F) {
+  return TargetTransformInfo(RISCVTTIImpl(this, F));
+}
+
 namespace {
 class RISCVPassConfig : public TargetPassConfig {
 public: