[AArch64] Improve v8.1-A code-gen for atomic load-and
Armv8.1-A added an atomic load-clear instruction (which performs bitwise
and with the complement of it's operand), but not a load-and
instruction. Our current code-generation for atomic load-and always
inserts an MVN instruction to invert its argument, even if it could be
folded into a constant or another instruction.
This adds lowering early in selection DAG to convert a load-and
operation into an xor with -1 and a load-clear, allowing the normal DAG
optimisations to work on it.
To do this, I've had to add a new ISD opcode, ATOMIC_LOAD_CLR. I don't
see any easy way to do this with an AArch64-specific ISD node, because
the code-generation for atomic operations assumes the SDNodes are of
type AtomicSDNode.
I've left the old tablegen patterns in because they are still needed for
global isel.
Differential revision: https://reviews.llvm.org/D42478
llvm-svn: 324908
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 1208d913..bb8b81a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3971,6 +3971,7 @@
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
+ case ISD::ATOMIC_LOAD_CLR:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index 31e8769..8ef7911 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -146,6 +146,7 @@
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
+ case ISD::ATOMIC_LOAD_CLR:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
@@ -1402,6 +1403,7 @@
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
+ case ISD::ATOMIC_LOAD_CLR:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 58c7c4e..68502fd 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -493,6 +493,7 @@
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
+ case ISD::ATOMIC_LOAD_CLR:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
@@ -5755,6 +5756,7 @@
assert((Opcode == ISD::ATOMIC_LOAD_ADD ||
Opcode == ISD::ATOMIC_LOAD_SUB ||
Opcode == ISD::ATOMIC_LOAD_AND ||
+ Opcode == ISD::ATOMIC_LOAD_CLR ||
Opcode == ISD::ATOMIC_LOAD_OR ||
Opcode == ISD::ATOMIC_LOAD_XOR ||
Opcode == ISD::ATOMIC_LOAD_NAND ||
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index b3aa462..a7db5da 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -85,6 +85,7 @@
case ISD::ATOMIC_LOAD_ADD: return "AtomicLoadAdd";
case ISD::ATOMIC_LOAD_SUB: return "AtomicLoadSub";
case ISD::ATOMIC_LOAD_AND: return "AtomicLoadAnd";
+ case ISD::ATOMIC_LOAD_CLR: return "AtomicLoadClr";
case ISD::ATOMIC_LOAD_OR: return "AtomicLoadOr";
case ISD::ATOMIC_LOAD_XOR: return "AtomicLoadXor";
case ISD::ATOMIC_LOAD_NAND: return "AtomicLoadNand";