[AArch64] Support SLC in ACLE prefetch intrinsics

This change:
- Modifies the ACLE code to allow the new SLC value (3) for the prefetch
  target.

- Introduces a new intrinsic, @llvm.aarch64.prefetch which matches the
  PRFM family instructions much more closely, and can represent all
  values for the PRFM immediate.

  The target-independent @llvm.prefetch intrinsic does not have enough
  information for us to be able to lower to it from the ACLE intrinsics
  correctly.

- Lowers the acle calls to the new intrinsic on aarch64 (the ARM
  lowering is unchanged).

- Implements code generation for the new intrinsic in both SelectionDAG
  and GlobalISel. We specifically choose to continue to support lowering
  the target-independent @llvm.prefetch intrinsic so that other
  frontends can continue to use it.

Differential Revision: https://reviews.llvm.org/D139443

1 files changed, 0 insertions, 23 deletions

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index bd96108..55aa9f6 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -9749,29 +9749,6 @@ Value *CodeGenFunction::EmitAArch64BuiltinExpr(unsigned BuiltinID,
     return Builder.CreateCall(F, llvm::ConstantInt::get(Int32Ty, HintID));
   }
 
-  if (BuiltinID == clang::AArch64::BI__builtin_arm_prefetch) {
-    Value *Address         = EmitScalarExpr(E->getArg(0));
-    Value *RW              = EmitScalarExpr(E->getArg(1));
-    Value *CacheLevel      = EmitScalarExpr(E->getArg(2));
-    Value *RetentionPolicy = EmitScalarExpr(E->getArg(3));
-    Value *IsData          = EmitScalarExpr(E->getArg(4));
-
-    Value *Locality = nullptr;
-    if (cast<llvm::ConstantInt>(RetentionPolicy)->isZero()) {
-      // Temporal fetch, needs to convert cache level to locality.
-      Locality = llvm::ConstantInt::get(Int32Ty,
-        -cast<llvm::ConstantInt>(CacheLevel)->getValue() + 3);
-    } else {
-      // Streaming fetch.
-      Locality = llvm::ConstantInt::get(Int32Ty, 0);
-    }
-
-    // FIXME: We need AArch64 specific LLVM intrinsic if we want to specify
-    // PLDL3STRM or PLDL2STRM.
-    Function *F = CGM.getIntrinsic(Intrinsic::prefetch, Address->getType());
-    return Builder.CreateCall(F, {Address, RW, Locality, IsData});
-  }
-
   if (BuiltinID == clang::AArch64::BI__builtin_arm_rbit) {
     assert((getContext().getTypeSize(E->getType()) == 32) &&
            "rbit of unusual size!");