140 lines · cpp
1//===- InlineHLFIRAssign.cpp - Inline hlfir.assign ops --------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8// Transform hlfir.assign array operations into loop nests performing element9// per element assignments. The inlining is done for trivial data types always,10// though, we may add performance/code-size heuristics in future.11//===----------------------------------------------------------------------===//12 13#include "flang/Optimizer/Analysis/AliasAnalysis.h"14#include "flang/Optimizer/Builder/FIRBuilder.h"15#include "flang/Optimizer/Builder/HLFIRTools.h"16#include "flang/Optimizer/HLFIR/HLFIROps.h"17#include "flang/Optimizer/HLFIR/Passes.h"18#include "flang/Optimizer/OpenMP/Passes.h"19#include "mlir/IR/PatternMatch.h"20#include "mlir/Pass/Pass.h"21#include "mlir/Support/LLVM.h"22#include "mlir/Transforms/GreedyPatternRewriteDriver.h"23 24namespace hlfir {25#define GEN_PASS_DEF_INLINEHLFIRASSIGN26#include "flang/Optimizer/HLFIR/Passes.h.inc"27} // namespace hlfir28 29#define DEBUG_TYPE "inline-hlfir-assign"30 31namespace {32/// Expand hlfir.assign of array RHS to array LHS into a loop nest33/// of element-by-element assignments:34/// hlfir.assign %4 to %5 : !fir.ref<!fir.array<3x3xf32>>,35/// !fir.ref<!fir.array<3x3xf32>>36/// into:37/// fir.do_loop %arg1 = %c1 to %c3 step %c1 unordered {38/// fir.do_loop %arg2 = %c1 to %c3 step %c1 unordered {39/// %6 = hlfir.designate %4 (%arg2, %arg1) :40/// (!fir.ref<!fir.array<3x3xf32>>, index, index) -> !fir.ref<f32>41/// %7 = fir.load %6 : !fir.ref<f32>42/// %8 = hlfir.designate %5 (%arg2, %arg1) :43/// (!fir.ref<!fir.array<3x3xf32>>, index, index) -> !fir.ref<f32>44/// hlfir.assign %7 to %8 : f32, !fir.ref<f32>45/// }46/// }47///48/// The transformation is correct only when LHS and RHS do not alias.49/// When RHS is an array expression, then there is no aliasing.50/// This transformation does not support runtime checking for51/// non-conforming LHS/RHS arrays' shapes currently.52class InlineHLFIRAssignConversion53 : public mlir::OpRewritePattern<hlfir::AssignOp> {54public:55 using mlir::OpRewritePattern<hlfir::AssignOp>::OpRewritePattern;56 57 llvm::LogicalResult58 matchAndRewrite(hlfir::AssignOp assign,59 mlir::PatternRewriter &rewriter) const override {60 if (assign.isAllocatableAssignment())61 return rewriter.notifyMatchFailure(assign,62 "AssignOp may imply allocation");63 64 hlfir::Entity rhs{assign.getRhs()};65 66 if (!rhs.isArray())67 return rewriter.notifyMatchFailure(assign,68 "AssignOp's RHS is not an array");69 70 mlir::Type rhsEleTy = rhs.getFortranElementType();71 if (!fir::isa_trivial(rhsEleTy))72 return rewriter.notifyMatchFailure(73 assign, "AssignOp's RHS data type is not trivial");74 75 hlfir::Entity lhs{assign.getLhs()};76 if (!lhs.isArray())77 return rewriter.notifyMatchFailure(assign,78 "AssignOp's LHS is not an array");79 80 mlir::Type lhsEleTy = lhs.getFortranElementType();81 if (!fir::isa_trivial(lhsEleTy))82 return rewriter.notifyMatchFailure(83 assign, "AssignOp's LHS data type is not trivial");84 85 if (lhsEleTy != rhsEleTy)86 return rewriter.notifyMatchFailure(assign,87 "RHS/LHS element types mismatch");88 89 if (!mlir::isa<hlfir::ExprType>(rhs.getType())) {90 // If RHS is not an hlfir.expr, then we should prove that91 // LHS and RHS do not alias.92 // TODO: if they may alias, we can insert hlfir.as_expr for RHS,93 // and proceed with the inlining.94 fir::AliasAnalysis aliasAnalysis;95 mlir::AliasResult aliasRes = aliasAnalysis.alias(lhs, rhs);96 // TODO: use areIdenticalOrDisjointSlices() from97 // OptimizedBufferization.cpp to check if we can still do the expansion.98 if (!aliasRes.isNo()) {99 LLVM_DEBUG(llvm::dbgs() << "InlineHLFIRAssign:\n"100 << "\tLHS: " << lhs << "\n"101 << "\tRHS: " << rhs << "\n"102 << "\tALIAS: " << aliasRes << "\n");103 return rewriter.notifyMatchFailure(assign, "RHS/LHS may alias");104 }105 }106 107 mlir::Location loc = assign->getLoc();108 fir::FirOpBuilder builder(rewriter, assign.getOperation());109 builder.setInsertionPoint(assign);110 hlfir::genNoAliasArrayAssignment(111 loc, builder, rhs, lhs, flangomp::shouldUseWorkshareLowering(assign));112 rewriter.eraseOp(assign);113 return mlir::success();114 }115};116 117class InlineHLFIRAssignPass118 : public hlfir::impl::InlineHLFIRAssignBase<InlineHLFIRAssignPass> {119public:120 void runOnOperation() override {121 mlir::MLIRContext *context = &getContext();122 123 mlir::GreedyRewriteConfig config;124 // Prevent the pattern driver from merging blocks.125 config.setRegionSimplificationLevel(126 mlir::GreedySimplifyRegionLevel::Disabled);127 128 mlir::RewritePatternSet patterns(context);129 patterns.insert<InlineHLFIRAssignConversion>(context);130 131 if (mlir::failed(mlir::applyPatternsGreedily(132 getOperation(), std::move(patterns), config))) {133 mlir::emitError(getOperation()->getLoc(),134 "failure in hlfir.assign inlining");135 signalPassFailure();136 }137 }138};139} // namespace140