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-rw-r--r--contrib/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp561
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diff --git a/contrib/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp b/contrib/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
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@@ -1,561 +0,0 @@
-//===-- LibCallsShrinkWrap.cpp ----------------------------------*- C++ -*-===//
-//
-// 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 shrink-wraps a call to function if the result is not used.
-// The call can set errno but is otherwise side effect free. For example:
-// sqrt(val);
-// is transformed to
-// if (val < 0)
-// sqrt(val);
-// Even if the result of library call is not being used, the compiler cannot
-// safely delete the call because the function can set errno on error
-// conditions.
-// Note in many functions, the error condition solely depends on the incoming
-// parameter. In this optimization, we can generate the condition can lead to
-// the errno to shrink-wrap the call. Since the chances of hitting the error
-// condition is low, the runtime call is effectively eliminated.
-//
-// These partially dead calls are usually results of C++ abstraction penalty
-// exposed by inlining.
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/GlobalsModRef.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
-#include "llvm/IR/CFG.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Dominators.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/InstVisitor.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/LLVMContext.h"
-#include "llvm/IR/MDBuilder.h"
-#include "llvm/Pass.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-using namespace llvm;
-
-#define DEBUG_TYPE "libcalls-shrinkwrap"
-
-STATISTIC(NumWrappedOneCond, "Number of One-Condition Wrappers Inserted");
-STATISTIC(NumWrappedTwoCond, "Number of Two-Condition Wrappers Inserted");
-
-namespace {
-class LibCallsShrinkWrapLegacyPass : public FunctionPass {
-public:
- static char ID; // Pass identification, replacement for typeid
- explicit LibCallsShrinkWrapLegacyPass() : FunctionPass(ID) {
- initializeLibCallsShrinkWrapLegacyPassPass(
- *PassRegistry::getPassRegistry());
- }
- void getAnalysisUsage(AnalysisUsage &AU) const override;
- bool runOnFunction(Function &F) override;
-};
-}
-
-char LibCallsShrinkWrapLegacyPass::ID = 0;
-INITIALIZE_PASS_BEGIN(LibCallsShrinkWrapLegacyPass, "libcalls-shrinkwrap",
- "Conditionally eliminate dead library calls", false,
- false)
-INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_END(LibCallsShrinkWrapLegacyPass, "libcalls-shrinkwrap",
- "Conditionally eliminate dead library calls", false, false)
-
-namespace {
-class LibCallsShrinkWrap : public InstVisitor<LibCallsShrinkWrap> {
-public:
- LibCallsShrinkWrap(const TargetLibraryInfo &TLI, DominatorTree *DT)
- : TLI(TLI), DT(DT){};
- void visitCallInst(CallInst &CI) { checkCandidate(CI); }
- bool perform() {
- bool Changed = false;
- for (auto &CI : WorkList) {
- LLVM_DEBUG(dbgs() << "CDCE calls: " << CI->getCalledFunction()->getName()
- << "\n");
- if (perform(CI)) {
- Changed = true;
- LLVM_DEBUG(dbgs() << "Transformed\n");
- }
- }
- return Changed;
- }
-
-private:
- bool perform(CallInst *CI);
- void checkCandidate(CallInst &CI);
- void shrinkWrapCI(CallInst *CI, Value *Cond);
- bool performCallDomainErrorOnly(CallInst *CI, const LibFunc &Func);
- bool performCallErrors(CallInst *CI, const LibFunc &Func);
- bool performCallRangeErrorOnly(CallInst *CI, const LibFunc &Func);
- Value *generateOneRangeCond(CallInst *CI, const LibFunc &Func);
- Value *generateTwoRangeCond(CallInst *CI, const LibFunc &Func);
- Value *generateCondForPow(CallInst *CI, const LibFunc &Func);
-
- // Create an OR of two conditions.
- Value *createOrCond(CallInst *CI, CmpInst::Predicate Cmp, float Val,
- CmpInst::Predicate Cmp2, float Val2) {
- IRBuilder<> BBBuilder(CI);
- Value *Arg = CI->getArgOperand(0);
- auto Cond2 = createCond(BBBuilder, Arg, Cmp2, Val2);
- auto Cond1 = createCond(BBBuilder, Arg, Cmp, Val);
- return BBBuilder.CreateOr(Cond1, Cond2);
- }
-
- // Create a single condition using IRBuilder.
- Value *createCond(IRBuilder<> &BBBuilder, Value *Arg, CmpInst::Predicate Cmp,
- float Val) {
- Constant *V = ConstantFP::get(BBBuilder.getContext(), APFloat(Val));
- if (!Arg->getType()->isFloatTy())
- V = ConstantExpr::getFPExtend(V, Arg->getType());
- return BBBuilder.CreateFCmp(Cmp, Arg, V);
- }
-
- // Create a single condition.
- Value *createCond(CallInst *CI, CmpInst::Predicate Cmp, float Val) {
- IRBuilder<> BBBuilder(CI);
- Value *Arg = CI->getArgOperand(0);
- return createCond(BBBuilder, Arg, Cmp, Val);
- }
-
- const TargetLibraryInfo &TLI;
- DominatorTree *DT;
- SmallVector<CallInst *, 16> WorkList;
-};
-} // end anonymous namespace
-
-// Perform the transformation to calls with errno set by domain error.
-bool LibCallsShrinkWrap::performCallDomainErrorOnly(CallInst *CI,
- const LibFunc &Func) {
- Value *Cond = nullptr;
-
- switch (Func) {
- case LibFunc_acos: // DomainError: (x < -1 || x > 1)
- case LibFunc_acosf: // Same as acos
- case LibFunc_acosl: // Same as acos
- case LibFunc_asin: // DomainError: (x < -1 || x > 1)
- case LibFunc_asinf: // Same as asin
- case LibFunc_asinl: // Same as asin
- {
- ++NumWrappedTwoCond;
- Cond = createOrCond(CI, CmpInst::FCMP_OLT, -1.0f, CmpInst::FCMP_OGT, 1.0f);
- break;
- }
- case LibFunc_cos: // DomainError: (x == +inf || x == -inf)
- case LibFunc_cosf: // Same as cos
- case LibFunc_cosl: // Same as cos
- case LibFunc_sin: // DomainError: (x == +inf || x == -inf)
- case LibFunc_sinf: // Same as sin
- case LibFunc_sinl: // Same as sin
- {
- ++NumWrappedTwoCond;
- Cond = createOrCond(CI, CmpInst::FCMP_OEQ, INFINITY, CmpInst::FCMP_OEQ,
- -INFINITY);
- break;
- }
- case LibFunc_acosh: // DomainError: (x < 1)
- case LibFunc_acoshf: // Same as acosh
- case LibFunc_acoshl: // Same as acosh
- {
- ++NumWrappedOneCond;
- Cond = createCond(CI, CmpInst::FCMP_OLT, 1.0f);
- break;
- }
- case LibFunc_sqrt: // DomainError: (x < 0)
- case LibFunc_sqrtf: // Same as sqrt
- case LibFunc_sqrtl: // Same as sqrt
- {
- ++NumWrappedOneCond;
- Cond = createCond(CI, CmpInst::FCMP_OLT, 0.0f);
- break;
- }
- default:
- return false;
- }
- shrinkWrapCI(CI, Cond);
- return true;
-}
-
-// Perform the transformation to calls with errno set by range error.
-bool LibCallsShrinkWrap::performCallRangeErrorOnly(CallInst *CI,
- const LibFunc &Func) {
- Value *Cond = nullptr;
-
- switch (Func) {
- case LibFunc_cosh:
- case LibFunc_coshf:
- case LibFunc_coshl:
- case LibFunc_exp:
- case LibFunc_expf:
- case LibFunc_expl:
- case LibFunc_exp10:
- case LibFunc_exp10f:
- case LibFunc_exp10l:
- case LibFunc_exp2:
- case LibFunc_exp2f:
- case LibFunc_exp2l:
- case LibFunc_sinh:
- case LibFunc_sinhf:
- case LibFunc_sinhl: {
- Cond = generateTwoRangeCond(CI, Func);
- break;
- }
- case LibFunc_expm1: // RangeError: (709, inf)
- case LibFunc_expm1f: // RangeError: (88, inf)
- case LibFunc_expm1l: // RangeError: (11356, inf)
- {
- Cond = generateOneRangeCond(CI, Func);
- break;
- }
- default:
- return false;
- }
- shrinkWrapCI(CI, Cond);
- return true;
-}
-
-// Perform the transformation to calls with errno set by combination of errors.
-bool LibCallsShrinkWrap::performCallErrors(CallInst *CI,
- const LibFunc &Func) {
- Value *Cond = nullptr;
-
- switch (Func) {
- case LibFunc_atanh: // DomainError: (x < -1 || x > 1)
- // PoleError: (x == -1 || x == 1)
- // Overall Cond: (x <= -1 || x >= 1)
- case LibFunc_atanhf: // Same as atanh
- case LibFunc_atanhl: // Same as atanh
- {
- ++NumWrappedTwoCond;
- Cond = createOrCond(CI, CmpInst::FCMP_OLE, -1.0f, CmpInst::FCMP_OGE, 1.0f);
- break;
- }
- case LibFunc_log: // DomainError: (x < 0)
- // PoleError: (x == 0)
- // Overall Cond: (x <= 0)
- case LibFunc_logf: // Same as log
- case LibFunc_logl: // Same as log
- case LibFunc_log10: // Same as log
- case LibFunc_log10f: // Same as log
- case LibFunc_log10l: // Same as log
- case LibFunc_log2: // Same as log
- case LibFunc_log2f: // Same as log
- case LibFunc_log2l: // Same as log
- case LibFunc_logb: // Same as log
- case LibFunc_logbf: // Same as log
- case LibFunc_logbl: // Same as log
- {
- ++NumWrappedOneCond;
- Cond = createCond(CI, CmpInst::FCMP_OLE, 0.0f);
- break;
- }
- case LibFunc_log1p: // DomainError: (x < -1)
- // PoleError: (x == -1)
- // Overall Cond: (x <= -1)
- case LibFunc_log1pf: // Same as log1p
- case LibFunc_log1pl: // Same as log1p
- {
- ++NumWrappedOneCond;
- Cond = createCond(CI, CmpInst::FCMP_OLE, -1.0f);
- break;
- }
- case LibFunc_pow: // DomainError: x < 0 and y is noninteger
- // PoleError: x == 0 and y < 0
- // RangeError: overflow or underflow
- case LibFunc_powf:
- case LibFunc_powl: {
- Cond = generateCondForPow(CI, Func);
- if (Cond == nullptr)
- return false;
- break;
- }
- default:
- return false;
- }
- assert(Cond && "performCallErrors should not see an empty condition");
- shrinkWrapCI(CI, Cond);
- return true;
-}
-
-// Checks if CI is a candidate for shrinkwrapping and put it into work list if
-// true.
-void LibCallsShrinkWrap::checkCandidate(CallInst &CI) {
- if (CI.isNoBuiltin())
- return;
- // A possible improvement is to handle the calls with the return value being
- // used. If there is API for fast libcall implementation without setting
- // errno, we can use the same framework to direct/wrap the call to the fast
- // API in the error free path, and leave the original call in the slow path.
- if (!CI.use_empty())
- return;
-
- LibFunc Func;
- Function *Callee = CI.getCalledFunction();
- if (!Callee)
- return;
- if (!TLI.getLibFunc(*Callee, Func) || !TLI.has(Func))
- return;
-
- if (CI.getNumArgOperands() == 0)
- return;
- // TODO: Handle long double in other formats.
- Type *ArgType = CI.getArgOperand(0)->getType();
- if (!(ArgType->isFloatTy() || ArgType->isDoubleTy() ||
- ArgType->isX86_FP80Ty()))
- return;
-
- WorkList.push_back(&CI);
-}
-
-// Generate the upper bound condition for RangeError.
-Value *LibCallsShrinkWrap::generateOneRangeCond(CallInst *CI,
- const LibFunc &Func) {
- float UpperBound;
- switch (Func) {
- case LibFunc_expm1: // RangeError: (709, inf)
- UpperBound = 709.0f;
- break;
- case LibFunc_expm1f: // RangeError: (88, inf)
- UpperBound = 88.0f;
- break;
- case LibFunc_expm1l: // RangeError: (11356, inf)
- UpperBound = 11356.0f;
- break;
- default:
- llvm_unreachable("Unhandled library call!");
- }
-
- ++NumWrappedOneCond;
- return createCond(CI, CmpInst::FCMP_OGT, UpperBound);
-}
-
-// Generate the lower and upper bound condition for RangeError.
-Value *LibCallsShrinkWrap::generateTwoRangeCond(CallInst *CI,
- const LibFunc &Func) {
- float UpperBound, LowerBound;
- switch (Func) {
- case LibFunc_cosh: // RangeError: (x < -710 || x > 710)
- case LibFunc_sinh: // Same as cosh
- LowerBound = -710.0f;
- UpperBound = 710.0f;
- break;
- case LibFunc_coshf: // RangeError: (x < -89 || x > 89)
- case LibFunc_sinhf: // Same as coshf
- LowerBound = -89.0f;
- UpperBound = 89.0f;
- break;
- case LibFunc_coshl: // RangeError: (x < -11357 || x > 11357)
- case LibFunc_sinhl: // Same as coshl
- LowerBound = -11357.0f;
- UpperBound = 11357.0f;
- break;
- case LibFunc_exp: // RangeError: (x < -745 || x > 709)
- LowerBound = -745.0f;
- UpperBound = 709.0f;
- break;
- case LibFunc_expf: // RangeError: (x < -103 || x > 88)
- LowerBound = -103.0f;
- UpperBound = 88.0f;
- break;
- case LibFunc_expl: // RangeError: (x < -11399 || x > 11356)
- LowerBound = -11399.0f;
- UpperBound = 11356.0f;
- break;
- case LibFunc_exp10: // RangeError: (x < -323 || x > 308)
- LowerBound = -323.0f;
- UpperBound = 308.0f;
- break;
- case LibFunc_exp10f: // RangeError: (x < -45 || x > 38)
- LowerBound = -45.0f;
- UpperBound = 38.0f;
- break;
- case LibFunc_exp10l: // RangeError: (x < -4950 || x > 4932)
- LowerBound = -4950.0f;
- UpperBound = 4932.0f;
- break;
- case LibFunc_exp2: // RangeError: (x < -1074 || x > 1023)
- LowerBound = -1074.0f;
- UpperBound = 1023.0f;
- break;
- case LibFunc_exp2f: // RangeError: (x < -149 || x > 127)
- LowerBound = -149.0f;
- UpperBound = 127.0f;
- break;
- case LibFunc_exp2l: // RangeError: (x < -16445 || x > 11383)
- LowerBound = -16445.0f;
- UpperBound = 11383.0f;
- break;
- default:
- llvm_unreachable("Unhandled library call!");
- }
-
- ++NumWrappedTwoCond;
- return createOrCond(CI, CmpInst::FCMP_OGT, UpperBound, CmpInst::FCMP_OLT,
- LowerBound);
-}
-
-// For pow(x,y), We only handle the following cases:
-// (1) x is a constant && (x >= 1) && (x < MaxUInt8)
-// Cond is: (y > 127)
-// (2) x is a value coming from an integer type.
-// (2.1) if x's bit_size == 8
-// Cond: (x <= 0 || y > 128)
-// (2.2) if x's bit_size is 16
-// Cond: (x <= 0 || y > 64)
-// (2.3) if x's bit_size is 32
-// Cond: (x <= 0 || y > 32)
-// Support for powl(x,y) and powf(x,y) are TBD.
-//
-// Note that condition can be more conservative than the actual condition
-// (i.e. we might invoke the calls that will not set the errno.).
-//
-Value *LibCallsShrinkWrap::generateCondForPow(CallInst *CI,
- const LibFunc &Func) {
- // FIXME: LibFunc_powf and powl TBD.
- if (Func != LibFunc_pow) {
- LLVM_DEBUG(dbgs() << "Not handled powf() and powl()\n");
- return nullptr;
- }
-
- Value *Base = CI->getArgOperand(0);
- Value *Exp = CI->getArgOperand(1);
- IRBuilder<> BBBuilder(CI);
-
- // Constant Base case.
- if (ConstantFP *CF = dyn_cast<ConstantFP>(Base)) {
- double D = CF->getValueAPF().convertToDouble();
- if (D < 1.0f || D > APInt::getMaxValue(8).getZExtValue()) {
- LLVM_DEBUG(dbgs() << "Not handled pow(): constant base out of range\n");
- return nullptr;
- }
-
- ++NumWrappedOneCond;
- Constant *V = ConstantFP::get(CI->getContext(), APFloat(127.0f));
- if (!Exp->getType()->isFloatTy())
- V = ConstantExpr::getFPExtend(V, Exp->getType());
- return BBBuilder.CreateFCmp(CmpInst::FCMP_OGT, Exp, V);
- }
-
- // If the Base value coming from an integer type.
- Instruction *I = dyn_cast<Instruction>(Base);
- if (!I) {
- LLVM_DEBUG(dbgs() << "Not handled pow(): FP type base\n");
- return nullptr;
- }
- unsigned Opcode = I->getOpcode();
- if (Opcode == Instruction::UIToFP || Opcode == Instruction::SIToFP) {
- unsigned BW = I->getOperand(0)->getType()->getPrimitiveSizeInBits();
- float UpperV = 0.0f;
- if (BW == 8)
- UpperV = 128.0f;
- else if (BW == 16)
- UpperV = 64.0f;
- else if (BW == 32)
- UpperV = 32.0f;
- else {
- LLVM_DEBUG(dbgs() << "Not handled pow(): type too wide\n");
- return nullptr;
- }
-
- ++NumWrappedTwoCond;
- Constant *V = ConstantFP::get(CI->getContext(), APFloat(UpperV));
- Constant *V0 = ConstantFP::get(CI->getContext(), APFloat(0.0f));
- if (!Exp->getType()->isFloatTy())
- V = ConstantExpr::getFPExtend(V, Exp->getType());
- if (!Base->getType()->isFloatTy())
- V0 = ConstantExpr::getFPExtend(V0, Exp->getType());
-
- Value *Cond = BBBuilder.CreateFCmp(CmpInst::FCMP_OGT, Exp, V);
- Value *Cond0 = BBBuilder.CreateFCmp(CmpInst::FCMP_OLE, Base, V0);
- return BBBuilder.CreateOr(Cond0, Cond);
- }
- LLVM_DEBUG(dbgs() << "Not handled pow(): base not from integer convert\n");
- return nullptr;
-}
-
-// Wrap conditions that can potentially generate errno to the library call.
-void LibCallsShrinkWrap::shrinkWrapCI(CallInst *CI, Value *Cond) {
- assert(Cond != nullptr && "ShrinkWrapCI is not expecting an empty call inst");
- MDNode *BranchWeights =
- MDBuilder(CI->getContext()).createBranchWeights(1, 2000);
-
- Instruction *NewInst =
- SplitBlockAndInsertIfThen(Cond, CI, false, BranchWeights, DT);
- BasicBlock *CallBB = NewInst->getParent();
- CallBB->setName("cdce.call");
- BasicBlock *SuccBB = CallBB->getSingleSuccessor();
- assert(SuccBB && "The split block should have a single successor");
- SuccBB->setName("cdce.end");
- CI->removeFromParent();
- CallBB->getInstList().insert(CallBB->getFirstInsertionPt(), CI);
- LLVM_DEBUG(dbgs() << "== Basic Block After ==");
- LLVM_DEBUG(dbgs() << *CallBB->getSinglePredecessor() << *CallBB
- << *CallBB->getSingleSuccessor() << "\n");
-}
-
-// Perform the transformation to a single candidate.
-bool LibCallsShrinkWrap::perform(CallInst *CI) {
- LibFunc Func;
- Function *Callee = CI->getCalledFunction();
- assert(Callee && "perform() should apply to a non-empty callee");
- TLI.getLibFunc(*Callee, Func);
- assert(Func && "perform() is not expecting an empty function");
-
- if (performCallDomainErrorOnly(CI, Func) || performCallRangeErrorOnly(CI, Func))
- return true;
- return performCallErrors(CI, Func);
-}
-
-void LibCallsShrinkWrapLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addPreserved<DominatorTreeWrapperPass>();
- AU.addPreserved<GlobalsAAWrapperPass>();
- AU.addRequired<TargetLibraryInfoWrapperPass>();
-}
-
-static bool runImpl(Function &F, const TargetLibraryInfo &TLI,
- DominatorTree *DT) {
- if (F.hasFnAttribute(Attribute::OptimizeForSize))
- return false;
- LibCallsShrinkWrap CCDCE(TLI, DT);
- CCDCE.visit(F);
- bool Changed = CCDCE.perform();
-
-// Verify the dominator after we've updated it locally.
- assert(!DT || DT->verify(DominatorTree::VerificationLevel::Fast));
- return Changed;
-}
-
-bool LibCallsShrinkWrapLegacyPass::runOnFunction(Function &F) {
- auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
- auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
- auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
- return runImpl(F, TLI, DT);
-}
-
-namespace llvm {
-char &LibCallsShrinkWrapPassID = LibCallsShrinkWrapLegacyPass::ID;
-
-// Public interface to LibCallsShrinkWrap pass.
-FunctionPass *createLibCallsShrinkWrapPass() {
- return new LibCallsShrinkWrapLegacyPass();
-}
-
-PreservedAnalyses LibCallsShrinkWrapPass::run(Function &F,
- FunctionAnalysisManager &FAM) {
- auto &TLI = FAM.getResult<TargetLibraryAnalysis>(F);
- auto *DT = FAM.getCachedResult<DominatorTreeAnalysis>(F);
- if (!runImpl(F, TLI, DT))
- return PreservedAnalyses::all();
- auto PA = PreservedAnalyses();
- PA.preserve<GlobalsAA>();
- PA.preserve<DominatorTreeAnalysis>();
- return PA;
-}
-}
generated by cgit v1.2.3 (git 2.25.1) at 2025-11-03 14:36:10 +0000