[X86] Change the addcarry and subborrow intrinsics to return 2 results and remove the pointer argument.

We should represent the store directly in IR instead. This gives the middle end a chance to remove it if it can see a load from the same address.

Differential Revision: https://reviews.llvm.org/D51769

llvm-svn: 341677

1 files changed, 58 insertions, 0 deletions

diff --git a/llvm/lib/IR/AutoUpgrade.cpp b/llvm/lib/IR/AutoUpgrade.cpp
index 06db01fc196..171f82edf20 100644
--- a/llvm/lib/IR/AutoUpgrade.cpp
+++ b/llvm/lib/IR/AutoUpgrade.cpp
@@ -65,6 +65,17 @@ static bool UpgradeX86IntrinsicsWith8BitMask(Function *F, Intrinsic::ID IID,
   return true;
 }
 
+static bool UpgradeADCSBBIntrinsic(Function *F, Intrinsic::ID IID,
+                                   Function *&NewFn) {
+  // If this intrinsic has 3 operands, it's the new version.
+  if (F->getFunctionType()->getNumParams() == 3)
+    return false;
+
+  rename(F);
+  NewFn = Intrinsic::getDeclaration(F->getParent(), IID);
+  return true;
+}
+
 static bool ShouldUpgradeX86Intrinsic(Function *F, StringRef Name) {
   // All of the intrinsics matches below should be marked with which llvm
   // version started autoupgrading them. At some point in the future we would
@@ -371,6 +382,19 @@ static bool UpgradeX86IntrinsicFunction(Function *F, StringRef Name,
     return true;
   }
 
+  if (Name == "addcarryx.u32")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_addcarryx_u32, NewFn);
+  if (Name == "addcarryx.u64")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_addcarryx_u64, NewFn);
+  if (Name == "addcarry.u32")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_addcarry_u32, NewFn);
+  if (Name == "addcarry.u64")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_addcarry_u64, NewFn);
+  if (Name == "subborrow.u32")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_subborrow_u32, NewFn);
+  if (Name == "subborrow.u64")
+    return UpgradeADCSBBIntrinsic(F, Intrinsic::x86_subborrow_u64, NewFn);
+
   // SSE4.1 ptest functions may have an old signature.
   if (Name.startswith("sse41.ptest")) { // Added in 3.2
     if (Name.substr(11) == "c")
@@ -3417,6 +3441,40 @@ void llvm::UpgradeIntrinsicCall(CallInst *CI, Function *NewFn) {
     break;
   }
 
+  case Intrinsic::x86_addcarryx_u32:
+  case Intrinsic::x86_addcarryx_u64:
+  case Intrinsic::x86_addcarry_u32:
+  case Intrinsic::x86_addcarry_u64:
+  case Intrinsic::x86_subborrow_u32:
+  case Intrinsic::x86_subborrow_u64: {
+    // This used to take 4 arguments. If we only have 3 arguments its already
+    // upgraded.
+    if (CI->getNumOperands() == 3)
+      return;
+
+    // Make a call with 3 operands.
+    NewCall = Builder.CreateCall(NewFn, { CI->getArgOperand(0),
+                                          CI->getArgOperand(1),
+                                          CI->getArgOperand(2)});
+    // Extract the second result and store it.
+    Value *Data = Builder.CreateExtractValue(NewCall, 1);
+    // Cast the pointer to the right type.
+    Value *Ptr = Builder.CreateBitCast(CI->getArgOperand(3),
+                                 llvm::PointerType::getUnqual(Data->getType()));
+    Builder.CreateAlignedStore(Data, Ptr, 1);
+    // Replace the original call result with the first result of the new call.
+    Value *CF = Builder.CreateExtractValue(NewCall, 0);
+
+    std::string Name = CI->getName();
+    if (!Name.empty()) {
+      CI->setName(Name + ".old");
+      NewCall->setName(Name);
+    }
+    CI->replaceAllUsesWith(CF);
+    CI->eraseFromParent();
+    return;
+  }
+
   case Intrinsic::x86_sse41_insertps:
   case Intrinsic::x86_sse41_dppd:
   case Intrinsic::x86_sse41_dpps: