Allow 16 bit floating point operand for LLVM_AtomicRMWOp

As far as AMDGPU target supports vectorization for atomic_rmw operation,
allow construction of LLVM_AtomicRMWOp with 16 bit floating point values.
This patch enables building of LLVM_AtomicRMWOp with fixed vectors of
16 bit fp values as operands.

See also: llvm#94845, llvm#95393, llvm#95394

Signed-off-by: Ilya Veselov <[email protected]>

Author: joviliast

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

@@ -1737,7 +1737,8 @@ def LLVM_ConstantOp
 // Atomic operations.
 //
 
-def LLVM_AtomicRMWType : AnyTypeOf<[LLVM_AnyFloat, LLVM_AnyPointer, AnySignlessInteger]>;
+def LLVM_AtomicRMWType
+    : AnyTypeOf<[LLVM_AnyFloat, LLVM_AnyPointer, AnySignlessInteger, LLVM_AnyFixedVector]>;
 
 def LLVM_AtomicRMWOp : LLVM_MemAccessOpBase<"atomicrmw", [
       TypesMatchWith<"result #0 and operand #1 have the same type",

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -3008,9 +3008,17 @@ void AtomicRMWOp::build(OpBuilder &builder, OperationState &state,
 
 LogicalResult AtomicRMWOp::verify() {
   auto valType = getVal().getType();
-  if (getBinOp() == AtomicBinOp::fadd || getBinOp() == AtomicBinOp::fsub ||
-      getBinOp() == AtomicBinOp::fmin || getBinOp() == AtomicBinOp::fmax) {
-    if (!mlir::LLVM::isCompatibleFloatingPointType(valType))
+  if (getBinOp() == AtomicBinOp::fadd && isCompatibleVectorType(valType)) {
+    Type elemType = getVectorElementType(valType);
+    // Only 16 bit floating point elements are supported for now.
+    if (!(isCompatibleFloatingPointType(elemType) &&
+          elemType.getIntOrFloatBitWidth() == 16))
+      return emitOpError("unexpected LLVM IR type for vector element");
+  } else if (getBinOp() == AtomicBinOp::fadd ||
+             getBinOp() == AtomicBinOp::fsub ||
+             getBinOp() == AtomicBinOp::fmin ||
+             getBinOp() == AtomicBinOp::fmax) {
+    if (!isCompatibleFloatingPointType(valType))
       return emitOpError("expected LLVM IR floating point type");
   } else if (getBinOp() == AtomicBinOp::xchg) {
     DataLayout dataLayout = DataLayout::closest(*this);

mlir/test/Dialect/LLVMIR/invalid.mlir

@@ -643,6 +643,14 @@ func.func @atomicrmw_expected_float(%i32_ptr : !llvm.ptr, %i32 : i32) {
 
 // -----
 
+func.func @atomicrmw_unexpected_vector_element(%ptr : !llvm.ptr, %f32_vec : vector<3xf32>) {
+  // expected-error@+1 {{unexpected LLVM IR type for vector element}}
+  %0 = llvm.atomicrmw fadd %ptr, %f32_vec unordered : !llvm.ptr, vector<3xf32>
+  llvm.return
+}
+
+// -----
+
 func.func @atomicrmw_unexpected_xchg_type(%i1_ptr : !llvm.ptr, %i1 : i1) {
   // expected-error@+1 {{unexpected LLVM IR type for 'xchg' bin_op}}
   %0 = llvm.atomicrmw xchg %i1_ptr, %i1 unordered : !llvm.ptr, i1

mlir/test/Dialect/LLVMIR/roundtrip.mlir

@@ -420,11 +420,13 @@ func.func @atomic_store(%val : f32, %large_val : i256, %ptr : !llvm.ptr) {
 }
 
 // CHECK-LABEL: @atomicrmw
-func.func @atomicrmw(%ptr : !llvm.ptr, %val : f32) {
+func.func @atomicrmw(%ptr : !llvm.ptr, %val : f32, %f16_vec : vector<2xf16>) {
   // CHECK: llvm.atomicrmw fadd %{{.*}}, %{{.*}} monotonic : !llvm.ptr, f32
   %0 = llvm.atomicrmw fadd %ptr, %val monotonic : !llvm.ptr, f32
   // CHECK: llvm.atomicrmw volatile fsub %{{.*}}, %{{.*}} syncscope("singlethread") monotonic {alignment = 16 : i64} : !llvm.ptr, f32
   %1 = llvm.atomicrmw volatile fsub %ptr, %val syncscope("singlethread") monotonic {alignment = 16 : i64} : !llvm.ptr, f32
+  // CHECK: llvm.atomicrmw fadd %{{.*}}, %{{.*}} monotonic : !llvm.ptr, vector<2xf16>
+  %2 = llvm.atomicrmw fadd %ptr, %f16_vec monotonic : !llvm.ptr, vector<2xf16>
   llvm.return
 }
 

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -1496,7 +1496,8 @@ llvm.func @elements_constant_3d_array() -> !llvm.array<2 x array<2 x array<2 x i
 // CHECK-LABEL: @atomicrmw
 llvm.func @atomicrmw(
     %f32_ptr : !llvm.ptr, %f32 : f32,
-    %i32_ptr : !llvm.ptr, %i32 : i32) {
+    %i32_ptr : !llvm.ptr, %i32 : i32,
+    %f16_vec_ptr : !llvm.ptr, %f16_vec : vector<2xf16>) {
   // CHECK: atomicrmw fadd ptr %{{.*}}, float %{{.*}} monotonic
   %0 = llvm.atomicrmw fadd %f32_ptr, %f32 monotonic : !llvm.ptr, f32
   // CHECK: atomicrmw fsub ptr %{{.*}}, float %{{.*}} monotonic
@@ -1535,11 +1536,13 @@ llvm.func @atomicrmw(
   %17 = llvm.atomicrmw usub_cond %i32_ptr, %i32 monotonic : !llvm.ptr, i32
   // CHECK: atomicrmw usub_sat ptr %{{.*}}, i32 %{{.*}} monotonic
   %18 = llvm.atomicrmw usub_sat %i32_ptr, %i32 monotonic : !llvm.ptr, i32
+  // CHECK: atomicrmw fadd ptr %{{.*}}, <2 x half> %{{.*}} monotonic
+  %19 = llvm.atomicrmw fadd %f16_vec_ptr, %f16_vec monotonic : !llvm.ptr, vector<2xf16>
 
   // CHECK: atomicrmw volatile
   // CHECK-SAME:  syncscope("singlethread")
   // CHECK-SAME:  align 8
-  %19 = llvm.atomicrmw volatile udec_wrap %i32_ptr, %i32 syncscope("singlethread") monotonic {alignment = 8 : i64} : !llvm.ptr, i32
+  %20 = llvm.atomicrmw volatile udec_wrap %i32_ptr, %i32 syncscope("singlethread") monotonic {alignment = 8 : i64} : !llvm.ptr, i32
   llvm.return
 }