1 files changed, 67 insertions, 3 deletions

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index bf96e772394..5d219995aed 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -22,6 +22,7 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instruction.h"
+#include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/IR/Verifier.h"
@@ -522,6 +523,37 @@ static bool UpgradeIntrinsicFunction1(Function *F, Function *&NewFn) {
         return true;
       }
     }
+    // Updating the memory intrinsics (memcpy/memmove/memset) that have an
+    // alignment parameter to embedding the alignment as an attribute of
+    // the pointer args.
+    if (Name.startswith("memcpy.") && F->arg_size() == 5) {
+      rename(F);
+      // Get the types of dest, src, and len
+      ArrayRef<Type *> ParamTypes = F->getFunctionType()->params().slice(0, 3);
+      NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::memcpy,
+                                        ParamTypes);
+      return true;
+    }
+    if (Name.startswith("memmove.") && F->arg_size() == 5) {
+      rename(F);
+      // Get the types of dest, src, and len
+      ArrayRef<Type *> ParamTypes = F->getFunctionType()->params().slice(0, 3);
+      NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::memmove,
+                                        ParamTypes);
+      return true;
+    }
+    if (Name.startswith("memset.") && F->arg_size() == 5) {
+      rename(F);
+      // Get the types of dest, and len
+      const auto *FT = F->getFunctionType();
+      Type *ParamTypes[2] = {
+          FT->getParamType(0), // Dest
+          FT->getParamType(2)  // len
+      };
+      NewFn = Intrinsic::getDeclaration(F->getParent(), Intrinsic::memset,
+                                        ParamTypes);
+      return true;
+    }
     break;
   }
   case 'n': {
@@ -2198,14 +2230,17 @@ void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
     return;
   }
 
-  CallInst *NewCall = nullptr;
-  switch (NewFn->getIntrinsicID()) {
-  default: {
+  const auto &DefaultCase = [&NewFn, &CI]() -> void {
     // Handle generic mangling change, but nothing else
     assert(
         (CI->getCalledFunction()->getName() != NewFn->getName()) &&
         "Unknown function for CallInst upgrade and isn't just a name change");
     CI->setCalledFunction(NewFn);
+  };
+  CallInst *NewCall = nullptr;
+  switch (NewFn->getIntrinsicID()) {
+  default: {
+    DefaultCase();
     return;
   }
 
@@ -2346,6 +2381,35 @@ void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
     NewCall = Builder.CreateCall(NewFn, Args);
     break;
   }
+
+  case Intrinsic::memcpy:
+  case Intrinsic::memmove:
+  case Intrinsic::memset: {
+    // We have to make sure that the call signature is what we're expecting.
+    // We only want to change the old signatures by removing the alignment arg:
+    //  @llvm.mem[cpy|move]...(i8*, i8*, i[32|i64], i32, i1)
+    //    -> @llvm.mem[cpy|move]...(i8*, i8*, i[32|i64], i1)
+    //  @llvm.memset...(i8*, i8, i[32|64], i32, i1)
+    //    -> @llvm.memset...(i8*, i8, i[32|64], i1)
+    // Note: i8*'s in the above can be any pointer type
+    if (CI->getNumArgOperands() != 5) {
+      DefaultCase();
+      return;
+    }
+    // Remove alignment argument (3), and add alignment attributes to the
+    // dest/src pointers.
+    Value *Args[4] = {CI->getArgOperand(0), CI->getArgOperand(1),
+                      CI->getArgOperand(2), CI->getArgOperand(4)};
+    NewCall = Builder.CreateCall(NewFn, Args);
+    auto *MemCI = cast<MemIntrinsic>(NewCall);
+    // All mem intrinsics support dest alignment.
+    const ConstantInt *Align = cast<ConstantInt>(CI->getArgOperand(3));
+    MemCI->setDestAlignment(Align->getZExtValue());
+    // Memcpy/Memmove also support source alignment.
+    if (auto *MTI = dyn_cast<MemTransferInst>(MemCI))
+      MTI->setSourceAlignment(Align->getZExtValue());
+    break;
+  }
   }
   assert(NewCall && "Should have either set this variable or returned through "
                     "the default case");