Implement strip.invariant.group

Summary:
This patch introduce new intrinsic -
strip.invariant.group that was described in the
RFC: Devirtualization v2

Reviewers: rsmith, hfinkel, nlopes, sanjoy, amharc, kuhar

Subscribers: arsenm, nhaehnle, JDevlieghere, hiraditya, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47103

Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 336073

1 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 08c571f664e..38e018f6db0 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1393,6 +1393,7 @@ bool llvm::canConstantFoldCallTo(ImmutableCallSite CS, const Function *F) {
   case Intrinsic::fmuladd:
   case Intrinsic::copysign:
   case Intrinsic::launder_invariant_group:
+  case Intrinsic::strip_invariant_group:
   case Intrinsic::round:
   case Intrinsic::masked_load:
   case Intrinsic::sadd_with_overflow:
@@ -1596,14 +1597,16 @@ Constant *ConstantFoldScalarCall(StringRef Name, unsigned IntrinsicID, Type *Ty,
         return Constant::getNullValue(Ty);
       if (IntrinsicID == Intrinsic::bswap ||
           IntrinsicID == Intrinsic::bitreverse ||
-          IntrinsicID == Intrinsic::launder_invariant_group)
+          IntrinsicID == Intrinsic::launder_invariant_group ||
+          IntrinsicID == Intrinsic::strip_invariant_group)
         return Operands[0];
     }
 
     if (isa<ConstantPointerNull>(Operands[0]) &&
         Operands[0]->getType()->getPointerAddressSpace() == 0) {
-      // launder(null) == null iff in addrspace 0
-      if (IntrinsicID == Intrinsic::launder_invariant_group)
+      // launder(null) == null == strip(null) iff in addrspace 0
+      if (IntrinsicID == Intrinsic::launder_invariant_group ||
+          IntrinsicID == Intrinsic::strip_invariant_group)
         return Operands[0];
       return nullptr;
     }