[PATCH] D64414: Do not set ReadNone attribute on intrinsics with side effects

[Momchil Velikov via Phabricator via llvm-commits]

chill created this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

If an intrinsic is defined without outputs, but having side effects, it still can be removed completely from
the program. This patch make TableGen not set `Attribute::ReadNone` for intrinsics which
are declared with `IntrHasSideEffects`.


https://reviews.llvm.org/D64414

Files:
  llvm/utils/TableGen/CodeGenDAGPatterns.cpp
  llvm/utils/TableGen/IntrinsicEmitter.cpp


Index: llvm/utils/TableGen/IntrinsicEmitter.cpp
===================================================================
--- llvm/utils/TableGen/IntrinsicEmitter.cpp
+++ llvm/utils/TableGen/IntrinsicEmitter.cpp
@@ -685,7 +685,7 @@
     }
 
     if (!intrinsic.canThrow ||
-        intrinsic.ModRef != CodeGenIntrinsic::ReadWriteMem ||
+        (intrinsic.ModRef != CodeGenIntrinsic::ReadWriteMem && !intrinsic.hasSideEffects) ||
         intrinsic.isNoReturn || intrinsic.isCold || intrinsic.isNoDuplicate ||
         intrinsic.isConvergent || intrinsic.isSpeculatable) {
       OS << "      const Attribute::AttrKind Atts[] = {";
@@ -727,6 +727,8 @@
 
       switch (intrinsic.ModRef) {
       case CodeGenIntrinsic::NoMem:
+        if (intrinsic.hasSideEffects)
+          break;
         if (addComma)
           OS << ",";
         OS << "Attribute::ReadNone";
Index: llvm/utils/TableGen/CodeGenDAGPatterns.cpp
===================================================================
--- llvm/utils/TableGen/CodeGenDAGPatterns.cpp
+++ llvm/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -2779,7 +2779,7 @@
     // chain.
     if (Int.IS.RetVTs.empty())
       Operator = getDAGPatterns().get_intrinsic_void_sdnode();
-    else if (Int.ModRef != CodeGenIntrinsic::NoMem)
+    else if (Int.ModRef != CodeGenIntrinsic::NoMem || Int.hasSideEffects)
       // Has side-effects, requires chain.
       Operator = getDAGPatterns().get_intrinsic_w_chain_sdnode();
     else // Otherwise, no chain.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D64414.208663.patch
Type: text/x-patch
Size: 1478 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190709/c69b9ff7/attachment.bin>