[llvm] [RISCV] Introduce pass to promote double constants to a global array (PR #160536)

[Craig Topper via llvm-commits]

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+//==- RISCVPromoteConstant.cpp - Promote constant fp to global for RISC-V --==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCV.h"
+#include "RISCVSubtarget.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Constant.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/Debug.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "riscv-promote-const"
+#define RISCV_PROMOTE_CONSTANT_NAME "RISC-V Promote Constants"
+
+STATISTIC(NumPromoted, "Number of constant literals promoted to globals");
+STATISTIC(NumPromotedUses, "Number of uses of promoted literal constants");
+
+namespace {
+
+class RISCVPromoteConstant : public ModulePass {
+public:
+  static char ID;
+  RISCVPromoteConstant() : ModulePass(ID) {}
+
+  StringRef getPassName() const override { return RISCV_PROMOTE_CONSTANT_NAME; }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetPassConfig>();
+    AU.setPreservesCFG();
+  }
+
+  /// Iterate over the functions and promote the double fp constants that
+  /// would otherwise go into the constant pool to a constant array.
+  bool runOnModule(Module &M) override {
+    // TargetMachine and Subtarget are needed to query isFPImmlegal.
+    const TargetPassConfig &TPC = getAnalysis<TargetPassConfig>();
+    const TargetMachine &TM = TPC.getTM<TargetMachine>();
+    if (skipModule(M))
----------------
topperc wrote:

Do skipModule before assigning TPC and TPM?

https://github.com/llvm/llvm-project/pull/160536