[llvm] [RISCV] Remove getPostRAMutations (PR #117527)

[Pengcheng Wang via llvm-commits]

https://github.com/wangpc-pp created https://github.com/llvm/llvm-project/pull/117527

We are using `PostMachineScheduler` instead of `PostRAScheduler`
since #68696.

The hook `getPostRAMutations` is only used in `PostRAScheduler` so
it is actually dead code for RISC-V now.


>From 6c089aa8dc143e26d9cdf064c4857501f6b875e8 Mon Sep 17 00:00:00 2001
From: Wang Pengcheng <wangpengcheng.pp at bytedance.com>
Date: Mon, 25 Nov 2024 16:03:59 +0800
Subject: [PATCH] [RISCV] Remove getPostRAMutations

We are using `PostMachineScheduler` instead of `PostRAScheduler`
since #68696.

The hook `getPostRAMutations` is only used in `PostRAScheduler` so
it is actually dead code for RISC-V now.
---
 llvm/lib/Target/RISCV/RISCVSubtarget.cpp | 5 -----
 llvm/lib/Target/RISCV/RISCVSubtarget.h   | 3 ---
 2 files changed, 8 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.cpp b/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
index 03397e1e0d89ee..426d3682049046 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
@@ -186,11 +186,6 @@ bool RISCVSubtarget::useRVVForFixedLengthVectors() const {
 
 bool RISCVSubtarget::enableSubRegLiveness() const { return true; }
 
-void RISCVSubtarget::getPostRAMutations(
-    std::vector<std::unique_ptr<ScheduleDAGMutation>> &Mutations) const {
-  Mutations.push_back(createMacroFusionDAGMutation(getMacroFusions()));
-}
-
   /// Enable use of alias analysis during code generation (during MI
   /// scheduling, DAGCombine, etc.).
 bool RISCVSubtarget::useAA() const { return UseAA; }
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
index f2c0a3d85c998a..043838e13b964d 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -301,9 +301,6 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
 
   bool enableSubRegLiveness() const override;
 
-  void getPostRAMutations(std::vector<std::unique_ptr<ScheduleDAGMutation>>
-                              &Mutations) const override;
-
   bool useAA() const override;
 
   unsigned getCacheLineSize() const override {