Extend kernel outlining to also consider dim worth inlining.

PiperOrigin-RevId: 281483447
llvm · Nov 20, 2019 · abb6266 · abb6266
1 parent 88368a1
commit abb6266
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Showing 2 changed files with 22 additions and 10 deletions.
diff --git a/mlir/lib/Dialect/GPU/Transforms/KernelOutlining.cpp b/mlir/lib/Dialect/GPU/Transforms/KernelOutlining.cpp
@@ -56,22 +56,34 @@ static void injectGpuIndexOperations(Location loc, FuncOp kernelFunc) {
   }
 }
 
-// Move all constant arguments of the given kernel function into the function,
-// thereby reducing the number of kernel arguments.
-static gpu::LaunchFuncOp inlineConstants(FuncOp kernelFunc,
-                                         gpu::LaunchFuncOp launch) {
+static bool isInliningBeneficiary(Operation *op) {
+  return isa<ConstantOp>(op) || isa<DimOp>(op);
+}
+
+// Move arguments of the given kernel function into the function if this reduces
+// the number of kernel arguments.
+static gpu::LaunchFuncOp inlineBeneficiaryOps(FuncOp kernelFunc,
+                                              gpu::LaunchFuncOp launch) {
   OpBuilder kernelBuilder(kernelFunc.getBody());
   auto &firstBlock = kernelFunc.getBody().front();
   llvm::SmallVector<Value *, 8> newLaunchArgs;
+  BlockAndValueMapping map;
+  for (int i = 0, e = launch.getNumKernelOperands(); i < e; ++i) {
+    map.map(launch.getKernelOperand(i), kernelFunc.getArgument(i));
+  }
   for (int i = launch.getNumKernelOperands() - 1; i >= 0; --i) {
     auto operandOp = launch.getKernelOperand(i)->getDefiningOp();
-    auto constant = dyn_cast_or_null<ConstantOp>(operandOp);
-    if (!constant) {
+    if (!operandOp || !isInliningBeneficiary(operandOp)) {
       newLaunchArgs.push_back(launch.getKernelOperand(i));
       continue;
     }
-    auto newConstant = kernelBuilder.clone(*operandOp);
-    firstBlock.getArgument(i)->replaceAllUsesWith(newConstant->getResult(0));
+    // Only inline operations that do not create new arguments.
+    if (!llvm::all_of(operandOp->getOperands(),
+                      [map](Value *value) { return map.contains(value); })) {
+      continue;
+    }
+    auto clone = kernelBuilder.clone(*operandOp, map);
+    firstBlock.getArgument(i)->replaceAllUsesWith(clone->getResult(0));
     firstBlock.eraseArgument(i);
   }
   if (newLaunchArgs.size() == launch.getNumKernelOperands())
@@ -125,7 +137,7 @@ static void convertToLaunchFuncOp(gpu::LaunchOp &launchOp, FuncOp kernelFunc) {
   auto launchFuncOp = builder.create<gpu::LaunchFuncOp>(
       launchOp.getLoc(), kernelFunc, launchOp.getGridSizeOperandValues(),
       launchOp.getBlockSizeOperandValues(), kernelOperandValues);
-  inlineConstants(kernelFunc, launchFuncOp);
+  inlineBeneficiaryOps(kernelFunc, launchFuncOp);
   launchOp.erase();
 }
 

diff --git a/mlir/test/Dialect/GPU/outlining.mlir b/mlir/test/Dialect/GPU/outlining.mlir
@@ -92,7 +92,7 @@ func @extra_constants(%arg0 : memref<?xf32>) {
   // CHECK: %[[CST:.*]] = constant 8 : index
   %cst = constant 8 : index
   %cst2 = constant 2 : index
-  %cst3 = constant 3 : index
+  %cst3 = dim %arg0, 0 : memref<?xf32>
   // CHECK: "gpu.launch_func"(%[[CST]], %[[CST]], %[[CST]], %[[CST]], %[[CST]], %[[CST]], %{{.*}}) {kernel = "extra_constants_kernel", kernel_module = @extra_constants_kernel} : (index, index, index, index, index, index, memref<?xf32>) -> ()
   gpu.launch blocks(%bx, %by, %bz) in (%grid_x = %cst, %grid_y = %cst,
                                        %grid_z = %cst)