Imported Upstream version 5.18.0.179

Former-commit-id: 67aa10e65b237e1c4537630979ee99ebe1374215

external/llvm/lib/CodeGen/PreISelIntrinsicLowering.cpp

@@ -0,0 +1,96 @@
+//===- PreISelIntrinsicLowering.cpp - Pre-ISel intrinsic lowering pass ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass implements IR lowering for the llvm.load.relative intrinsic.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/PreISelIntrinsicLowering.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Type.h"
+#include "llvm/IR/User.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/Casting.h"
+
+using namespace llvm;
+
+static bool lowerLoadRelative(Function &F) {
+  if (F.use_empty())
+    return false;
+
+  bool Changed = false;
+  Type *Int32Ty = Type::getInt32Ty(F.getContext());
+  Type *Int32PtrTy = Int32Ty->getPointerTo();
+  Type *Int8Ty = Type::getInt8Ty(F.getContext());
+
+  for (auto I = F.use_begin(), E = F.use_end(); I != E;) {
+    auto CI = dyn_cast<CallInst>(I->getUser());
+    ++I;
+    if (!CI || CI->getCalledValue() != &F)
+      continue;
+
+    IRBuilder<> B(CI);
+    Value *OffsetPtr =
+        B.CreateGEP(Int8Ty, CI->getArgOperand(0), CI->getArgOperand(1));
+    Value *OffsetPtrI32 = B.CreateBitCast(OffsetPtr, Int32PtrTy);
+    Value *OffsetI32 = B.CreateAlignedLoad(OffsetPtrI32, 4);
+
+    Value *ResultPtr = B.CreateGEP(Int8Ty, CI->getArgOperand(0), OffsetI32);
+
+    CI->replaceAllUsesWith(ResultPtr);
+    CI->eraseFromParent();
+    Changed = true;
+  }
+
+  return Changed;
+}
+
+static bool lowerIntrinsics(Module &M) {
+  bool Changed = false;
+  for (Function &F : M) {
+    if (F.getName().startswith("llvm.load.relative."))
+      Changed |= lowerLoadRelative(F);
+  }
+  return Changed;
+}
+
+namespace {
+
+class PreISelIntrinsicLoweringLegacyPass : public ModulePass {
+public:
+  static char ID;
+
+  PreISelIntrinsicLoweringLegacyPass() : ModulePass(ID) {}
+
+  bool runOnModule(Module &M) override { return lowerIntrinsics(M); }
+};
+
+} // end anonymous namespace
+
+char PreISelIntrinsicLoweringLegacyPass::ID;
+
+INITIALIZE_PASS(PreISelIntrinsicLoweringLegacyPass,
+                "pre-isel-intrinsic-lowering", "Pre-ISel Intrinsic Lowering",
+                false, false)
+
+ModulePass *llvm::createPreISelIntrinsicLoweringPass() {
+  return new PreISelIntrinsicLoweringLegacyPass;
+}
+
+PreservedAnalyses PreISelIntrinsicLoweringPass::run(Module &M,
+                                                    ModuleAnalysisManager &AM) {
+  if (!lowerIntrinsics(M))
+    return PreservedAnalyses::all();
+  else
+    return PreservedAnalyses::none();
+}