Add IntrWrite[Arg]Mem intrinsic property

Summary:
This property is used to mark an intrinsic that only writes to memory, but
neither reads from memory nor has other side effects.

An example where this is useful is the llvm.amdgcn.buffer.store.format.*
intrinsic, which corresponds to a store instruction that goes through a special
buffer descriptor rather than through a plain pointer.

With this property, the intrinsic should still be handled as having side
effects at the LLVM IR level, but machine scheduling can make smarter
decisions.

Reviewers: tstellarAMD, arsenm, joker.eph, reames

Subscribers: arsenm, llvm-commits

Differential Revision: http://reviews.llvm.org/D18291

llvm-svn: 266826

2 files changed, 12 insertions, 1 deletions

diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index b67dfc4a1fc..aee029c4189 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -38,6 +38,17 @@ def IntrReadArgMem : IntrinsicProperty;
 // deleted if dead.
 def IntrReadMem : IntrinsicProperty;
 
+// IntrWriteMem - This intrinsic writes to unspecified memory, but does not
+// read from memory, and has no other side effects. This means dead stores
+// before calls to this intrinsics may be removed.
+def IntrWriteMem : IntrinsicProperty;
+
+// IntrWriteArgMem - This intrinsic writes only to memory that one of its
+// arguments points to, but may access an unspecified amount. The intrinsic
+// does not read from memory and has no other side effects. This means that
+// dead stores before calls to this intrinsics may be removed.
+def IntrWriteArgMem : IntrinsicProperty;
+
 // IntrReadWriteArgMem - This intrinsic reads and writes only from memory that
 // one of its arguments points to, but may access an unspecified amount.  The
 // reads and writes may be volatile, but except for this it has no other side
diff --git a/llvm/include/llvm/IR/IntrinsicsAMDGPU.td b/llvm/include/llvm/IR/IntrinsicsAMDGPU.td
index 24e8c040287..5c5128c4dc8 100644
--- a/llvm/include/llvm/IR/IntrinsicsAMDGPU.td
+++ b/llvm/include/llvm/IR/IntrinsicsAMDGPU.td
@@ -243,7 +243,7 @@ class AMDGPUBufferStore : Intrinsic <
    llvm_i32_ty,       // offset(SGPR/VGPR/imm)
    llvm_i1_ty,        // glc(imm)
    llvm_i1_ty],       // slc(imm)
-  []>;
+  [IntrWriteMem]>;
 def int_amdgcn_buffer_store_format : AMDGPUBufferStore;
 def int_amdgcn_buffer_store : AMDGPUBufferStore;