IR: Add fp operations to atomicrmw

Add just fadd/fsub for now.

llvm-svn: 351778

3 files changed, 27 insertions, 4 deletions

diff --git a/llvm/include/llvm/Bitcode/LLVMBitCodes.h b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
index e694331776c..ce853cd3998 100644
--- a/llvm/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/llvm/include/llvm/Bitcode/LLVMBitCodes.h
@@ -406,7 +406,9 @@ enum RMWOperations {
   RMW_MAX = 7,
   RMW_MIN = 8,
   RMW_UMAX = 9,
-  RMW_UMIN = 10
+  RMW_UMIN = 10,
+  RMW_FADD = 11,
+  RMW_FSUB = 12
 };
 
 /// OverflowingBinaryOperatorOptionalFlags - Flags for serializing
diff --git a/llvm/include/llvm/CodeGen/TargetLowering.h b/llvm/include/llvm/CodeGen/TargetLowering.h
index 3886ac54ed3..850b9e2d555 100644
--- a/llvm/include/llvm/CodeGen/TargetLowering.h
+++ b/llvm/include/llvm/CodeGen/TargetLowering.h
@@ -1715,8 +1715,9 @@ public:
 
   /// Returns how the IR-level AtomicExpand pass should expand the given
   /// AtomicRMW, if at all. Default is to never expand.
-  virtual AtomicExpansionKind shouldExpandAtomicRMWInIR(AtomicRMWInst *) const {
-    return AtomicExpansionKind::None;
+  virtual AtomicExpansionKind shouldExpandAtomicRMWInIR(AtomicRMWInst *RMW) const {
+    return RMW->isFloatingPointOperation() ?
+      AtomicExpansionKind::CmpXChg : AtomicExpansionKind::None;
   }
 
   /// On some platforms, an AtomicRMW that never actually modifies the value
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h
index c720dd8745e..beadf7313a2 100644
--- a/llvm/include/llvm/IR/Instructions.h
+++ b/llvm/include/llvm/IR/Instructions.h
@@ -724,8 +724,14 @@ public:
     /// *p = old <unsigned v ? old : v
     UMin,
 
+    /// *p = old + v
+    FAdd,
+
+    /// *p = old - v
+    FSub,
+
     FIRST_BINOP = Xchg,
-    LAST_BINOP = UMin,
+    LAST_BINOP = FSub,
     BAD_BINOP
   };
 
@@ -747,6 +753,16 @@ public:
 
   static StringRef getOperationName(BinOp Op);
 
+  static bool isFPOperation(BinOp Op) {
+    switch (Op) {
+    case AtomicRMWInst::FAdd:
+    case AtomicRMWInst::FSub:
+      return true;
+    default:
+      return false;
+    }
+  }
+
   void setOperation(BinOp Operation) {
     unsigned short SubclassData = getSubclassDataFromInstruction();
     setInstructionSubclassData((SubclassData & 31) |
@@ -804,6 +820,10 @@ public:
     return getPointerOperand()->getType()->getPointerAddressSpace();
   }
 
+  bool isFloatingPointOperation() const {
+    return isFPOperation(getOperation());
+  }
+
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Instruction *I) {
     return I->getOpcode() == Instruction::AtomicRMW;