llvm/lib/Target/SPIRV/SPIRVStripConvergentIntrinsics.cpp

   1 //===-- SPIRVStripConvergentIntrinsics.cpp ----------------------*- C++ -*-===//
   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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This pass trims convergence intrinsics as those were only useful when
  10 // modifying the CFG during IR passes.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "SPIRV.h"
  15 #include "SPIRVSubtarget.h"
  16 #include "SPIRVTargetMachine.h"
  17 #include "SPIRVUtils.h"
  18 #include "llvm/CodeGen/IntrinsicLowering.h"
  19 #include "llvm/IR/IRBuilder.h"
  20 #include "llvm/IR/IntrinsicInst.h"
  21 #include "llvm/IR/Intrinsics.h"
  22 #include "llvm/IR/IntrinsicsSPIRV.h"
  23 #include "llvm/Transforms/Utils/Cloning.h"
  24 #include "llvm/Transforms/Utils/LowerMemIntrinsics.h"
  25
  26 using namespace llvm;
  27
  28 namespace llvm {
  29 void initializeSPIRVStripConvergentIntrinsicsPass(PassRegistry &);
  30 }
  31
  32 class SPIRVStripConvergentIntrinsics : public FunctionPass {
  33 public:
  34   static char ID;
  35
  36   SPIRVStripConvergentIntrinsics() : FunctionPass(ID) {
  37     initializeSPIRVStripConvergentIntrinsicsPass(
  38         *PassRegistry::getPassRegistry());
  39   };
  40
  41   virtual bool runOnFunction(Function &F) override {
  42     DenseSet<Instruction *> ToRemove;
  43
  44     for (BasicBlock &BB : F) {
  45       for (Instruction &I : BB) {
  46         if (auto *II = dyn_cast<IntrinsicInst>(&I)) {
  47           if (II->getIntrinsicID() !=
  48                   Intrinsic::experimental_convergence_entry &&
  49               II->getIntrinsicID() !=
  50                   Intrinsic::experimental_convergence_loop &&
  51               II->getIntrinsicID() !=
  52                   Intrinsic::experimental_convergence_anchor) {
  53             continue;
  54           }
  55
  56           II->replaceAllUsesWith(UndefValue::get(II->getType()));
  57           ToRemove.insert(II);
  58         } else if (auto *CI = dyn_cast<CallInst>(&I)) {
  59           auto OB = CI->getOperandBundle(LLVMContext::OB_convergencectrl);
  60           if (!OB.has_value())
  61             continue;
  62
  63           auto *NewCall = CallBase::removeOperandBundle(
  64               CI, LLVMContext::OB_convergencectrl, CI);
  65           NewCall->copyMetadata(*CI);
  66           CI->replaceAllUsesWith(NewCall);
  67           ToRemove.insert(CI);
  68         }
  69       }
  70     }
  71
  72     // All usages must be removed before their definition is removed.
  73     for (Instruction *I : ToRemove)
  74       I->eraseFromParent();
  75
  76     return ToRemove.size() != 0;
  77   }
  78 };
  79
  80 char SPIRVStripConvergentIntrinsics::ID = 0;
  81 INITIALIZE_PASS(SPIRVStripConvergentIntrinsics, "strip-convergent-intrinsics",
  82                 "SPIRV strip convergent intrinsics", false, false)
  83
  84 FunctionPass *llvm::createSPIRVStripConvergenceIntrinsicsPass() {
  85   return new SPIRVStripConvergentIntrinsics();
  86 }