1 files changed, 0 insertions, 308 deletions
diff --git a/contrib/llvm-project/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp b/contrib/llvm-project/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
deleted file mode 100644
index 8d05a72d68da..000000000000
--- a/contrib/llvm-project/llvm/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ /dev/null
@@ -1,308 +0,0 @@
-//===-- IPConstantPropagation.cpp - Propagate constants through calls -----===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-//
-// This pass implements an _extremely_ simple interprocedural constant
-// propagation pass.  It could certainly be improved in many different ways,
-// like using a worklist.  This pass makes arguments dead, but does not remove
-// them.  The existing dead argument elimination pass should be run after this
-// to clean up the mess.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/ValueTracking.h"
-#include "llvm/IR/AbstractCallSite.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Module.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
-#include "llvm/Transforms/IPO.h"
-using namespace llvm;
-
-#define DEBUG_TYPE "ipconstprop"
-
-STATISTIC(NumArgumentsProped, "Number of args turned into constants");
-STATISTIC(NumReturnValProped, "Number of return values turned into constants");
-
-namespace {
-  /// IPCP - The interprocedural constant propagation pass
-  ///
-  struct IPCP : public ModulePass {
-    static char ID; // Pass identification, replacement for typeid
-    IPCP() : ModulePass(ID) {
-      initializeIPCPPass(*PassRegistry::getPassRegistry());
-    }
-
-    bool runOnModule(Module &M) override;
-  };
-}
-
-/// PropagateConstantsIntoArguments - Look at all uses of the specified
-/// function.  If all uses are direct call sites, and all pass a particular
-/// constant in for an argument, propagate that constant in as the argument.
-///
-static bool PropagateConstantsIntoArguments(Function &F) {
-  if (F.arg_empty() || F.use_empty()) return false; // No arguments? Early exit.
-
-  // For each argument, keep track of its constant value and whether it is a
-  // constant or not.  The bool is driven to true when found to be non-constant.
-  SmallVector<PointerIntPair<Constant *, 1, bool>, 16> ArgumentConstants;
-  ArgumentConstants.resize(F.arg_size());
-
-  unsigned NumNonconstant = 0;
-  for (Use &U : F.uses()) {
-    User *UR = U.getUser();
-    // Ignore blockaddress uses.
-    if (isa<BlockAddress>(UR)) continue;
-
-    // If no abstract call site was created we did not understand the use, bail.
-    AbstractCallSite ACS(&U);
-    if (!ACS)
-      return false;
-
-    // Mismatched argument count is undefined behavior. Simply bail out to avoid
-    // handling of such situations below (avoiding asserts/crashes).
-    unsigned NumActualArgs = ACS.getNumArgOperands();
-    if (F.isVarArg() ? ArgumentConstants.size() > NumActualArgs
-                     : ArgumentConstants.size() != NumActualArgs)
-      return false;
-
-    // Check out all of the potentially constant arguments.  Note that we don't
-    // inspect varargs here.
-    Function::arg_iterator Arg = F.arg_begin();
-    for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++Arg) {
-
-      // If this argument is known non-constant, ignore it.
-      if (ArgumentConstants[i].getInt())
-        continue;
-
-      Value *V = ACS.getCallArgOperand(i);
-      Constant *C = dyn_cast_or_null<Constant>(V);
-
-      // Mismatched argument type is undefined behavior. Simply bail out to avoid
-      // handling of such situations below (avoiding asserts/crashes).
-      if (C && Arg->getType() != C->getType())
-        return false;
-
-      // We can only propagate thread independent values through callbacks.
-      // This is different to direct/indirect call sites because for them we
-      // know the thread executing the caller and callee is the same. For
-      // callbacks this is not guaranteed, thus a thread dependent value could
-      // be different for the caller and callee, making it invalid to propagate.
-      if (C && ACS.isCallbackCall() && C->isThreadDependent()) {
-        // Argument became non-constant. If all arguments are non-constant now,
-        // give up on this function.
-        if (++NumNonconstant == ArgumentConstants.size())
-          return false;
-
-        ArgumentConstants[i].setInt(true);
-        continue;
-      }
-
-      if (C && ArgumentConstants[i].getPointer() == nullptr) {
-        ArgumentConstants[i].setPointer(C); // First constant seen.
-      } else if (C && ArgumentConstants[i].getPointer() == C) {
-        // Still the constant value we think it is.
-      } else if (V == &*Arg) {
-        // Ignore recursive calls passing argument down.
-      } else {
-        // Argument became non-constant.  If all arguments are non-constant now,
-        // give up on this function.
-        if (++NumNonconstant == ArgumentConstants.size())
-          return false;
-        ArgumentConstants[i].setInt(true);
-      }
-    }
-  }
-
-  // If we got to this point, there is a constant argument!
-  assert(NumNonconstant != ArgumentConstants.size());
-  bool MadeChange = false;
-  Function::arg_iterator AI = F.arg_begin();
-  for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI) {
-    // Do we have a constant argument?
-    if (ArgumentConstants[i].getInt() || AI->use_empty() ||
-        (AI->hasByValAttr() && !F.onlyReadsMemory()))
-      continue;
-
-    Value *V = ArgumentConstants[i].getPointer();
-    if (!V) V = UndefValue::get(AI->getType());
-    AI->replaceAllUsesWith(V);
-    ++NumArgumentsProped;
-    MadeChange = true;
-  }
-  return MadeChange;
-}
-
-
-// Check to see if this function returns one or more constants. If so, replace
-// all callers that use those return values with the constant value. This will
-// leave in the actual return values and instructions, but deadargelim will
-// clean that up.
-//
-// Additionally if a function always returns one of its arguments directly,
-// callers will be updated to use the value they pass in directly instead of
-// using the return value.
-static bool PropagateConstantReturn(Function &F) {
-  if (F.getReturnType()->isVoidTy())
-    return false; // No return value.
-
-  // We can infer and propagate the return value only when we know that the
-  // definition we'll get at link time is *exactly* the definition we see now.
-  // For more details, see GlobalValue::mayBeDerefined.
-  if (!F.isDefinitionExact())
-    return false;
-
-  // Don't touch naked functions. The may contain asm returning
-  // value we don't see, so we may end up interprocedurally propagating
-  // the return value incorrectly.
-  if (F.hasFnAttribute(Attribute::Naked))
-    return false;
-
-  // Check to see if this function returns a constant.
-  SmallVector<Value *,4> RetVals;
-  StructType *STy = dyn_cast<StructType>(F.getReturnType());
-  if (STy)
-    for (unsigned i = 0, e = STy->getNumElements(); i < e; ++i)
-      RetVals.push_back(UndefValue::get(STy->getElementType(i)));
-  else
-    RetVals.push_back(UndefValue::get(F.getReturnType()));
-
-  unsigned NumNonConstant = 0;
-  for (BasicBlock &BB : F)
-    if (ReturnInst *RI = dyn_cast<ReturnInst>(BB.getTerminator())) {
-      for (unsigned i = 0, e = RetVals.size(); i != e; ++i) {
-        // Already found conflicting return values?
-        Value *RV = RetVals[i];
-        if (!RV)
-          continue;
-
-        // Find the returned value
-        Value *V;
-        if (!STy)
-          V = RI->getOperand(0);
-        else
-          V = FindInsertedValue(RI->getOperand(0), i);
-
-        if (V) {
-          // Ignore undefs, we can change them into anything
-          if (isa<UndefValue>(V))
-            continue;
-
-          // Try to see if all the rets return the same constant or argument.
-          if (isa<Constant>(V) || isa<Argument>(V)) {
-            if (isa<UndefValue>(RV)) {
-              // No value found yet? Try the current one.
-              RetVals[i] = V;
-              continue;
-            }
-            // Returning the same value? Good.
-            if (RV == V)
-              continue;
-          }
-        }
-        // Different or no known return value? Don't propagate this return
-        // value.
-        RetVals[i] = nullptr;
-        // All values non-constant? Stop looking.
-        if (++NumNonConstant == RetVals.size())
-          return false;
-      }
-    }
-
-  // If we got here, the function returns at least one constant value.  Loop
-  // over all users, replacing any uses of the return value with the returned
-  // constant.
-  bool MadeChange = false;
-  for (Use &U : F.uses()) {
-    CallBase *CB = dyn_cast<CallBase>(U.getUser());
-
-    // Not a call instruction or a call instruction that's not calling F
-    // directly?
-    if (!CB || !CB->isCallee(&U))
-      continue;
-
-    // Call result not used?
-    if (CB->use_empty())
-      continue;
-
-    MadeChange = true;
-
-    if (!STy) {
-      Value* New = RetVals[0];
-      if (Argument *A = dyn_cast<Argument>(New))
-        // Was an argument returned? Then find the corresponding argument in
-        // the call instruction and use that.
-        New = CB->getArgOperand(A->getArgNo());
-      CB->replaceAllUsesWith(New);
-      continue;
-    }
-
-    for (auto I = CB->user_begin(), E = CB->user_end(); I != E;) {
-      Instruction *Ins = cast<Instruction>(*I);
-
-      // Increment now, so we can remove the use
-      ++I;
-
-      // Find the index of the retval to replace with
-      int index = -1;
-      if (ExtractValueInst *EV = dyn_cast<ExtractValueInst>(Ins))
-        if (EV->getNumIndices() == 1)
-          index = *EV->idx_begin();
-
-      // If this use uses a specific return value, and we have a replacement,
-      // replace it.
-      if (index != -1) {
-        Value *New = RetVals[index];
-        if (New) {
-          if (Argument *A = dyn_cast<Argument>(New))
-            // Was an argument returned? Then find the corresponding argument in
-            // the call instruction and use that.
-            New = CB->getArgOperand(A->getArgNo());
-          Ins->replaceAllUsesWith(New);
-          Ins->eraseFromParent();
-        }
-      }
-    }
-  }
-
-  if (MadeChange) ++NumReturnValProped;
-  return MadeChange;
-}
-
-char IPCP::ID = 0;
-INITIALIZE_PASS(IPCP, "ipconstprop",
-                "Interprocedural constant propagation", false, false)
-
-ModulePass *llvm::createIPConstantPropagationPass() { return new IPCP(); }
-
-bool IPCP::runOnModule(Module &M) {
-  if (skipModule(M))
-    return false;
-
-  bool Changed = false;
-  bool LocalChange = true;
-
-  // FIXME: instead of using smart algorithms, we just iterate until we stop
-  // making changes.
-  while (LocalChange) {
-    LocalChange = false;
-    for (Function &F : M)
-      if (!F.isDeclaration()) {
-        // Delete any klingons.
-        F.removeDeadConstantUsers();
-        if (F.hasLocalLinkage())
-          LocalChange |= PropagateConstantsIntoArguments(F);
-        Changed |= PropagateConstantReturn(F);
-      }
-    Changed |= LocalChange;
-  }
-  return Changed;
-}