IR-change: cmpxchg operations now return { iN, i1 }.

This is a minimal fix for clang. I'll soon add support for generating
weak variants when requested, but that's not really necessary for the
LLVM change in isolation.

llvm-svn: 210907

3 files changed, 16 insertions, 13 deletions

diff --git a/clang/lib/CodeGen/CGAtomic.cpp b/clang/lib/CodeGen/CGAtomic.cpp
index 18eb065226c..ad4ba88dc15 100644
--- a/clang/lib/CodeGen/CGAtomic.cpp
+++ b/clang/lib/CodeGen/CGAtomic.cpp
@@ -186,13 +186,14 @@ static void emitAtomicCmpXchg(CodeGenFunction &CGF, AtomicExpr *E,
   llvm::LoadInst *Desired = CGF.Builder.CreateLoad(Val2);
   Desired->setAlignment(Align);
 
-  llvm::AtomicCmpXchgInst *Old = CGF.Builder.CreateAtomicCmpXchg(
+  llvm::AtomicCmpXchgInst *Pair = CGF.Builder.CreateAtomicCmpXchg(
       Ptr, Expected, Desired, SuccessOrder, FailureOrder);
-  Old->setVolatile(E->isVolatile());
+  Pair->setVolatile(E->isVolatile());
 
   // Cmp holds the result of the compare-exchange operation: true on success,
   // false on failure.
-  llvm::Value *Cmp = CGF.Builder.CreateICmpEQ(Old, Expected);
+  llvm::Value *Old = CGF.Builder.CreateExtractValue(Pair, 0);
+  llvm::Value *Cmp = CGF.Builder.CreateExtractValue(Pair, 1);
 
   // This basic block is used to hold the store instruction if the operation
   // failed.
diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index f705ed80c14..47245cf2d83 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -975,6 +975,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     Value *Result = Builder.CreateAtomicCmpXchg(Args[0], Args[1], Args[2],
                                                 llvm::SequentiallyConsistent,
                                                 llvm::SequentiallyConsistent);
+    Result = Builder.CreateExtractValue(Result, 0);
     Result = EmitFromInt(*this, Result, T, ValueType);
     return RValue::get(Result);
   }
@@ -998,11 +999,10 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
     Args[1] = EmitToInt(*this, EmitScalarExpr(E->getArg(1)), T, IntType);
     Args[2] = EmitToInt(*this, EmitScalarExpr(E->getArg(2)), T, IntType);
 
-    Value *OldVal = Args[1];
-    Value *PrevVal = Builder.CreateAtomicCmpXchg(Args[0], Args[1], Args[2],
-                                                 llvm::SequentiallyConsistent,
-                                                 llvm::SequentiallyConsistent);
-    Value *Result = Builder.CreateICmpEQ(PrevVal, OldVal);
+    Value *Pair = Builder.CreateAtomicCmpXchg(Args[0], Args[1], Args[2],
+                                              llvm::SequentiallyConsistent,
+                                              llvm::SequentiallyConsistent);
+    Value *Result = Builder.CreateExtractValue(Pair, 1);
     // zext bool to int.
     Result = Builder.CreateZExt(Result, ConvertType(E->getType()));
     return RValue::get(Result);
@@ -1524,7 +1524,7 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
         SequentiallyConsistent,
         SequentiallyConsistent);
       CXI->setVolatile(true);
-      return RValue::get(CXI);
+      return RValue::get(Builder.CreateExtractValue(CXI, 0));
   }
   case Builtin::BI_InterlockedIncrement: {
     AtomicRMWInst *RMWI = Builder.CreateAtomicRMW(
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 4dfa1696158..14ef5b79826 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -1732,11 +1732,12 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
   if (atomicPHI) {
     llvm::BasicBlock *opBB = Builder.GetInsertBlock();
     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
-    llvm::Value *old = Builder.CreateAtomicCmpXchg(
+    llvm::Value *pair = Builder.CreateAtomicCmpXchg(
         LV.getAddress(), atomicPHI, CGF.EmitToMemory(value, type),
         llvm::SequentiallyConsistent, llvm::SequentiallyConsistent);
+    llvm::Value *old = Builder.CreateExtractValue(pair, 0);
+    llvm::Value *success = Builder.CreateExtractValue(pair, 1);
     atomicPHI->addIncoming(old, opBB);
-    llvm::Value *success = Builder.CreateICmpEQ(old, atomicPHI);
     Builder.CreateCondBr(success, contBB, opBB);
     Builder.SetInsertPoint(contBB);
     return isPre ? value : input;
@@ -2075,11 +2076,12 @@ LValue ScalarExprEmitter::EmitCompoundAssignLValue(
   if (atomicPHI) {
     llvm::BasicBlock *opBB = Builder.GetInsertBlock();
     llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn);
-    llvm::Value *old = Builder.CreateAtomicCmpXchg(
+    llvm::Value *pair = Builder.CreateAtomicCmpXchg(
         LHSLV.getAddress(), atomicPHI, CGF.EmitToMemory(Result, LHSTy),
         llvm::SequentiallyConsistent, llvm::SequentiallyConsistent);
+    llvm::Value *old = Builder.CreateExtractValue(pair, 0);
+    llvm::Value *success = Builder.CreateExtractValue(pair, 1);
     atomicPHI->addIncoming(old, opBB);
-    llvm::Value *success = Builder.CreateICmpEQ(old, atomicPHI);
     Builder.CreateCondBr(success, contBB, opBB);
     Builder.SetInsertPoint(contBB);
     return LHSLV;