[PATCH] D22459: TableGen: Add IntrHasSideEffects property for intrinsics

[Tom Stellard via llvm-commits]

tstellarAMD created this revision.
tstellarAMD added reviewers: mehdi_amini, hfinkel, majnemer, eli.friedman.
tstellarAMD added a subscriber: llvm-commits.

The IntrNoMem, IntrReadMem, IntrWriteMem, and IntrArgMemOnly intrinsic
properties differ from their corresponding LLVM IR attributes by specifying
that the intrinsic, in addition to its memory properties, has no other side
effects.

The IntrHasSideEffects flag used in combination with one of the memory flags
listed above, makes it possible to define an intrinsic such that its
properties at the CodeGen layer match its properties at the IR layer.

https://reviews.llvm.org/D22459

Files:
  include/llvm/IR/Intrinsics.td
  utils/TableGen/CodeGenDAGPatterns.cpp
  utils/TableGen/CodeGenIntrinsics.h
  utils/TableGen/CodeGenTarget.cpp
  utils/TableGen/IntrinsicEmitter.cpp

Index: utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- utils/TableGen/IntrinsicEmitter.cpp
+++ utils/TableGen/IntrinsicEmitter.cpp
@@ -464,6 +464,9 @@
     if (L->isSpeculatable != R->isSpeculatable)
       return R->isSpeculatable;
 
+    if (L->hasSideEffects != R->hasSideEffects)
+      return R->hasSideEffects;
+
     // Try to order by readonly/readnone attribute.
     CodeGenIntrinsic::ModRefBehavior LK = L->ModRef;
     CodeGenIntrinsic::ModRefBehavior RK = R->ModRef;
Index: utils/TableGen/CodeGenTarget.cpp
===================================================================
--- utils/TableGen/CodeGenTarget.cpp
+++ utils/TableGen/CodeGenTarget.cpp
@@ -456,6 +456,7 @@
   isNoDuplicate = false;
   isConvergent = false;
   isSpeculatable = false;
+  hasSideEffects = false;
 
   if (DefName.size() <= 4 ||
       std::string(DefName.begin(), DefName.begin() + 4) != "int_")
@@ -592,6 +593,8 @@
       isNoReturn = true;
     else if (Property->getName() == "IntrSpeculatable")
       isSpeculatable = true;
+    else if (Property->getName() == "IntrHasSideEffects")
+      hasSideEffects = true;
     else if (Property->isSubClassOf("NoCapture")) {
       unsigned ArgNo = Property->getValueAsInt("ArgNo");
       ArgumentAttributes.push_back(std::make_pair(ArgNo, NoCapture));
Index: utils/TableGen/CodeGenIntrinsics.h
===================================================================
--- utils/TableGen/CodeGenIntrinsics.h
+++ utils/TableGen/CodeGenIntrinsics.h
@@ -108,6 +108,10 @@
   /// True if the intrinsic is marked as convergent.
   bool isConvergent;
 
+  /// True if the intrinsic has side effects that aren't captured by any
+  /// of the other flags.
+  bool hasSideEffects;
+
   // True if the intrinsic is marked as speculatable.
   bool isSpeculatable;
 
Index: utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- utils/TableGen/CodeGenDAGPatterns.cpp
+++ utils/TableGen/CodeGenDAGPatterns.cpp
@@ -2822,7 +2822,8 @@
       if (IntInfo->ModRef & CodeGenIntrinsic::MR_Mod)
         mayStore = true;// Intrinsics that can write to memory are 'mayStore'.
 
-      if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteMem)
+      if (IntInfo->ModRef >= CodeGenIntrinsic::ReadWriteMem ||
+          IntInfo->hasSideEffects)
         // ReadWriteMem intrinsics can have other strange effects.
         hasSideEffects = true;
     }
Index: include/llvm/IR/Intrinsics.td
===================================================================
--- include/llvm/IR/Intrinsics.td
+++ include/llvm/IR/Intrinsics.td
@@ -92,6 +92,15 @@
 // This property indicates that the intrinsic is safe to speculate.
 def IntrSpeculatable : IntrinsicProperty;
 
+// This property can be used to override the 'has no other side effects'
+// language of the IntrNoMem, IntrReadMem, IntrWriteMem, and IntrArgMemOnly
+// intrinsic properties.  By default, intrinsics are assumed to have side
+// effects, so this property is only necessary if you have defined one of
+// the memory properties listed above.
+// For this property, 'side effects' has the same meaning as 'side effects'
+// defined by the hasSideEffects property of the TableGen Instruction class.
+def IntrHasSideEffects : IntrinsicProperty;
+
 //===----------------------------------------------------------------------===//
 // Types used by intrinsics.
 //===----------------------------------------------------------------------===//


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