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llvm-mirror/unittests/Analysis/ScalarEvolutionTest.cpp
Florian Hahn 69f89dfbd9 [SCEV] Move ScalarEvolutionExpander.cpp to Transforms/Utils (NFC). 
SCEVExpander modifies the underlying function so it is more suitable in
Transforms/Utils, rather than Analysis. This allows using other
transform utils in SCEVExpander.

This patch was originally committed as b8a3c34eee06, but broke the
modules build, as LoopAccessAnalysis was using the Expander.

The code-gen part of LAA was moved to lib/Transforms recently, so this
patch can be landed again.

Reviewers: sanjoy.google, efriedma, reames

Reviewed By: sanjoy.google

Differential Revision: https://reviews.llvm.org/D71537
2020-05-20 10:53:40 +01:00

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//===- ScalarEvolutionsTest.cpp - ScalarEvolution unit tests --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/ScalarEvolutionNormalization.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
namespace llvm {
// We use this fixture to ensure that we clean up ScalarEvolution before
// deleting the PassManager.
class ScalarEvolutionsTest : public testing::Test {
protected:
LLVMContext Context;
Module M;
TargetLibraryInfoImpl TLII;
TargetLibraryInfo TLI;
std::unique_ptr<AssumptionCache> AC;
std::unique_ptr<DominatorTree> DT;
std::unique_ptr<LoopInfo> LI;
ScalarEvolutionsTest() : M("", Context), TLII(), TLI(TLII) {}
ScalarEvolution buildSE(Function &F) {
AC.reset(new AssumptionCache(F));
DT.reset(new DominatorTree(F));
LI.reset(new LoopInfo(*DT));
return ScalarEvolution(F, TLI, *AC, *DT, *LI);
}
void runWithSE(
Module &M, StringRef FuncName,
function_ref<void(Function &F, LoopInfo &LI, ScalarEvolution &SE)> Test) {
auto *F = M.getFunction(FuncName);
ASSERT_NE(F, nullptr) << "Could not find " << FuncName;
ScalarEvolution SE = buildSE(*F);
Test(*F, *LI, SE);
}
static Optional<APInt> computeConstantDifference(ScalarEvolution &SE,
const SCEV *LHS,
const SCEV *RHS) {
return SE.computeConstantDifference(LHS, RHS);
}
};
TEST_F(ScalarEvolutionsTest, SCEVUnknownRAUW) {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context),
std::vector<Type *>(), false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
BasicBlock *BB = BasicBlock::Create(Context, "entry", F);
ReturnInst::Create(Context, nullptr, BB);
Type *Ty = Type::getInt1Ty(Context);
Constant *Init = Constant::getNullValue(Ty);
Value *V0 = new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage, Init, "V0");
Value *V1 = new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage, Init, "V1");
Value *V2 = new GlobalVariable(M, Ty, false, GlobalValue::ExternalLinkage, Init, "V2");
ScalarEvolution SE = buildSE(*F);
const SCEV *S0 = SE.getSCEV(V0);
const SCEV *S1 = SE.getSCEV(V1);
const SCEV *S2 = SE.getSCEV(V2);
const SCEV *P0 = SE.getAddExpr(S0, S0);
const SCEV *P1 = SE.getAddExpr(S1, S1);
const SCEV *P2 = SE.getAddExpr(S2, S2);
const SCEVMulExpr *M0 = cast<SCEVMulExpr>(P0);
const SCEVMulExpr *M1 = cast<SCEVMulExpr>(P1);
const SCEVMulExpr *M2 = cast<SCEVMulExpr>(P2);
EXPECT_EQ(cast<SCEVConstant>(M0->getOperand(0))->getValue()->getZExtValue(),
2u);
EXPECT_EQ(cast<SCEVConstant>(M1->getOperand(0))->getValue()->getZExtValue(),
2u);
EXPECT_EQ(cast<SCEVConstant>(M2->getOperand(0))->getValue()->getZExtValue(),
2u);
// Before the RAUWs, these are all pointing to separate values.
EXPECT_EQ(cast<SCEVUnknown>(M0->getOperand(1))->getValue(), V0);
EXPECT_EQ(cast<SCEVUnknown>(M1->getOperand(1))->getValue(), V1);
EXPECT_EQ(cast<SCEVUnknown>(M2->getOperand(1))->getValue(), V2);
// Do some RAUWs.
V2->replaceAllUsesWith(V1);
V1->replaceAllUsesWith(V0);
// After the RAUWs, these should all be pointing to V0.
EXPECT_EQ(cast<SCEVUnknown>(M0->getOperand(1))->getValue(), V0);
EXPECT_EQ(cast<SCEVUnknown>(M1->getOperand(1))->getValue(), V0);
EXPECT_EQ(cast<SCEVUnknown>(M2->getOperand(1))->getValue(), V0);
}
TEST_F(ScalarEvolutionsTest, SimplifiedPHI) {
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context),
std::vector<Type *>(), false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
BasicBlock *LoopBB = BasicBlock::Create(Context, "loop", F);
BasicBlock *ExitBB = BasicBlock::Create(Context, "exit", F);
BranchInst::Create(LoopBB, EntryBB);
BranchInst::Create(LoopBB, ExitBB, UndefValue::get(Type::getInt1Ty(Context)),
LoopBB);
ReturnInst::Create(Context, nullptr, ExitBB);
auto *Ty = Type::getInt32Ty(Context);
auto *PN = PHINode::Create(Ty, 2, "", &*LoopBB->begin());
PN->addIncoming(Constant::getNullValue(Ty), EntryBB);
PN->addIncoming(UndefValue::get(Ty), LoopBB);
ScalarEvolution SE = buildSE(*F);
auto *S1 = SE.getSCEV(PN);
auto *S2 = SE.getSCEV(PN);
auto *ZeroConst = SE.getConstant(Ty, 0);
// At some point, only the first call to getSCEV returned the simplified
// SCEVConstant and later calls just returned a SCEVUnknown referencing the
// PHI node.
EXPECT_EQ(S1, ZeroConst);
EXPECT_EQ(S1, S2);
}
static Instruction *getInstructionByName(Function &F, StringRef Name) {
for (auto &I : instructions(F))
if (I.getName() == Name)
return &I;
llvm_unreachable("Expected to find instruction!");
}
TEST_F(ScalarEvolutionsTest, CommutativeExprOperandOrder) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(
"target datalayout = \"e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128\" "
" "
"@var_0 = external global i32, align 4"
"@var_1 = external global i32, align 4"
"@var_2 = external global i32, align 4"
" "
"declare i32 @unknown(i32, i32, i32)"
" "
"define void @f_1(i8* nocapture %arr, i32 %n, i32* %A, i32* %B) "
" local_unnamed_addr { "
"entry: "
" %entrycond = icmp sgt i32 %n, 0 "
" br i1 %entrycond, label %loop.ph, label %for.end "
" "
"loop.ph: "
" %a = load i32, i32* %A, align 4 "
" %b = load i32, i32* %B, align 4 "
" %mul = mul nsw i32 %b, %a "
" %iv0.init = getelementptr inbounds i8, i8* %arr, i32 %mul "
" br label %loop "
" "
"loop: "
" %iv0 = phi i8* [ %iv0.inc, %loop ], [ %iv0.init, %loop.ph ] "
" %iv1 = phi i32 [ %iv1.inc, %loop ], [ 0, %loop.ph ] "
" %conv = trunc i32 %iv1 to i8 "
" store i8 %conv, i8* %iv0, align 1 "
" %iv0.inc = getelementptr inbounds i8, i8* %iv0, i32 %b "
" %iv1.inc = add nuw nsw i32 %iv1, 1 "
" %exitcond = icmp eq i32 %iv1.inc, %n "
" br i1 %exitcond, label %for.end.loopexit, label %loop "
" "
"for.end.loopexit: "
" br label %for.end "
" "
"for.end: "
" ret void "
"} "
" "
"define void @f_2(i32* %X, i32* %Y, i32* %Z) { "
" %x = load i32, i32* %X "
" %y = load i32, i32* %Y "
" %z = load i32, i32* %Z "
" ret void "
"} "
" "
"define void @f_3() { "
" %x = load i32, i32* @var_0"
" %y = load i32, i32* @var_1"
" %z = load i32, i32* @var_2"
" ret void"
"} "
" "
"define void @f_4(i32 %a, i32 %b, i32 %c) { "
" %x = call i32 @unknown(i32 %a, i32 %b, i32 %c)"
" %y = call i32 @unknown(i32 %b, i32 %c, i32 %a)"
" %z = call i32 @unknown(i32 %c, i32 %a, i32 %b)"
" ret void"
"} "
,
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "f_1", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto *IV0 = getInstructionByName(F, "iv0");
auto *IV0Inc = getInstructionByName(F, "iv0.inc");
auto *FirstExprForIV0 = SE.getSCEV(IV0);
auto *FirstExprForIV0Inc = SE.getSCEV(IV0Inc);
auto *SecondExprForIV0 = SE.getSCEV(IV0);
EXPECT_TRUE(isa<SCEVAddRecExpr>(FirstExprForIV0));
EXPECT_TRUE(isa<SCEVAddRecExpr>(FirstExprForIV0Inc));
EXPECT_TRUE(isa<SCEVAddRecExpr>(SecondExprForIV0));
});
auto CheckCommutativeMulExprs = [&](ScalarEvolution &SE, const SCEV *A,
const SCEV *B, const SCEV *C) {
EXPECT_EQ(SE.getMulExpr(A, B), SE.getMulExpr(B, A));
EXPECT_EQ(SE.getMulExpr(B, C), SE.getMulExpr(C, B));
EXPECT_EQ(SE.getMulExpr(A, C), SE.getMulExpr(C, A));
SmallVector<const SCEV *, 3> Ops0 = {A, B, C};
SmallVector<const SCEV *, 3> Ops1 = {A, C, B};
SmallVector<const SCEV *, 3> Ops2 = {B, A, C};
SmallVector<const SCEV *, 3> Ops3 = {B, C, A};
SmallVector<const SCEV *, 3> Ops4 = {C, B, A};
SmallVector<const SCEV *, 3> Ops5 = {C, A, B};
auto *Mul0 = SE.getMulExpr(Ops0);
auto *Mul1 = SE.getMulExpr(Ops1);
auto *Mul2 = SE.getMulExpr(Ops2);
auto *Mul3 = SE.getMulExpr(Ops3);
auto *Mul4 = SE.getMulExpr(Ops4);
auto *Mul5 = SE.getMulExpr(Ops5);
EXPECT_EQ(Mul0, Mul1) << "Expected " << *Mul0 << " == " << *Mul1;
EXPECT_EQ(Mul1, Mul2) << "Expected " << *Mul1 << " == " << *Mul2;
EXPECT_EQ(Mul2, Mul3) << "Expected " << *Mul2 << " == " << *Mul3;
EXPECT_EQ(Mul3, Mul4) << "Expected " << *Mul3 << " == " << *Mul4;
EXPECT_EQ(Mul4, Mul5) << "Expected " << *Mul4 << " == " << *Mul5;
};
for (StringRef FuncName : {"f_2", "f_3", "f_4"})
runWithSE(
*M, FuncName, [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
CheckCommutativeMulExprs(SE, SE.getSCEV(getInstructionByName(F, "x")),
SE.getSCEV(getInstructionByName(F, "y")),
SE.getSCEV(getInstructionByName(F, "z")));
});
}
TEST_F(ScalarEvolutionsTest, CompareSCEVComplexity) {
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), std::vector<Type *>(), false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
BasicBlock *LoopBB = BasicBlock::Create(Context, "bb1", F);
BranchInst::Create(LoopBB, EntryBB);
auto *Ty = Type::getInt32Ty(Context);
SmallVector<Instruction*, 8> Muls(8), Acc(8), NextAcc(8);
Acc[0] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[1] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[2] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[3] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[4] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[5] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[6] = PHINode::Create(Ty, 2, "", LoopBB);
Acc[7] = PHINode::Create(Ty, 2, "", LoopBB);
for (int i = 0; i < 20; i++) {
Muls[0] = BinaryOperator::CreateMul(Acc[0], Acc[0], "", LoopBB);
NextAcc[0] = BinaryOperator::CreateAdd(Muls[0], Acc[4], "", LoopBB);
Muls[1] = BinaryOperator::CreateMul(Acc[1], Acc[1], "", LoopBB);
NextAcc[1] = BinaryOperator::CreateAdd(Muls[1], Acc[5], "", LoopBB);
Muls[2] = BinaryOperator::CreateMul(Acc[2], Acc[2], "", LoopBB);
NextAcc[2] = BinaryOperator::CreateAdd(Muls[2], Acc[6], "", LoopBB);
Muls[3] = BinaryOperator::CreateMul(Acc[3], Acc[3], "", LoopBB);
NextAcc[3] = BinaryOperator::CreateAdd(Muls[3], Acc[7], "", LoopBB);
Muls[4] = BinaryOperator::CreateMul(Acc[4], Acc[4], "", LoopBB);
NextAcc[4] = BinaryOperator::CreateAdd(Muls[4], Acc[0], "", LoopBB);
Muls[5] = BinaryOperator::CreateMul(Acc[5], Acc[5], "", LoopBB);
NextAcc[5] = BinaryOperator::CreateAdd(Muls[5], Acc[1], "", LoopBB);
Muls[6] = BinaryOperator::CreateMul(Acc[6], Acc[6], "", LoopBB);
NextAcc[6] = BinaryOperator::CreateAdd(Muls[6], Acc[2], "", LoopBB);
Muls[7] = BinaryOperator::CreateMul(Acc[7], Acc[7], "", LoopBB);
NextAcc[7] = BinaryOperator::CreateAdd(Muls[7], Acc[3], "", LoopBB);
Acc = NextAcc;
}
auto II = LoopBB->begin();
for (int i = 0; i < 8; i++) {
PHINode *Phi = cast<PHINode>(&*II++);
Phi->addIncoming(Acc[i], LoopBB);
Phi->addIncoming(UndefValue::get(Ty), EntryBB);
}
BasicBlock *ExitBB = BasicBlock::Create(Context, "bb2", F);
BranchInst::Create(LoopBB, ExitBB, UndefValue::get(Type::getInt1Ty(Context)),
LoopBB);
Acc[0] = BinaryOperator::CreateAdd(Acc[0], Acc[1], "", ExitBB);
Acc[1] = BinaryOperator::CreateAdd(Acc[2], Acc[3], "", ExitBB);
Acc[2] = BinaryOperator::CreateAdd(Acc[4], Acc[5], "", ExitBB);
Acc[3] = BinaryOperator::CreateAdd(Acc[6], Acc[7], "", ExitBB);
Acc[0] = BinaryOperator::CreateAdd(Acc[0], Acc[1], "", ExitBB);
Acc[1] = BinaryOperator::CreateAdd(Acc[2], Acc[3], "", ExitBB);
Acc[0] = BinaryOperator::CreateAdd(Acc[0], Acc[1], "", ExitBB);
ReturnInst::Create(Context, nullptr, ExitBB);
ScalarEvolution SE = buildSE(*F);
EXPECT_NE(nullptr, SE.getSCEV(Acc[0]));
}
TEST_F(ScalarEvolutionsTest, CompareValueComplexity) {
IntegerType *IntPtrTy = M.getDataLayout().getIntPtrType(Context);
PointerType *IntPtrPtrTy = IntPtrTy->getPointerTo();
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {IntPtrTy, IntPtrTy}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
Value *X = &*F->arg_begin();
Value *Y = &*std::next(F->arg_begin());
const int ValueDepth = 10;
for (int i = 0; i < ValueDepth; i++) {
X = new LoadInst(IntPtrTy, new IntToPtrInst(X, IntPtrPtrTy, "", EntryBB),
"",
/*isVolatile*/ false, EntryBB);
Y = new LoadInst(IntPtrTy, new IntToPtrInst(Y, IntPtrPtrTy, "", EntryBB),
"",
/*isVolatile*/ false, EntryBB);
}
auto *MulA = BinaryOperator::CreateMul(X, Y, "", EntryBB);
auto *MulB = BinaryOperator::CreateMul(Y, X, "", EntryBB);
ReturnInst::Create(Context, nullptr, EntryBB);
// This test isn't checking for correctness. Today making A and B resolve to
// the same SCEV would require deeper searching in CompareValueComplexity,
// which will slow down compilation. However, this test can fail (with LLVM's
// behavior still being correct) if we ever have a smarter
// CompareValueComplexity that is both fast and more accurate.
ScalarEvolution SE = buildSE(*F);
auto *A = SE.getSCEV(MulA);
auto *B = SE.getSCEV(MulB);
EXPECT_NE(A, B);
}
TEST_F(ScalarEvolutionsTest, SCEVAddExpr) {
Type *Ty32 = Type::getInt32Ty(Context);
Type *ArgTys[] = {Type::getInt64Ty(Context), Ty32};
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), ArgTys, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
Argument *A1 = &*F->arg_begin();
Argument *A2 = &*(std::next(F->arg_begin()));
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
Instruction *Trunc = CastInst::CreateTruncOrBitCast(A1, Ty32, "", EntryBB);
Instruction *Mul1 = BinaryOperator::CreateMul(Trunc, A2, "", EntryBB);
Instruction *Add1 = BinaryOperator::CreateAdd(Mul1, Trunc, "", EntryBB);
Mul1 = BinaryOperator::CreateMul(Add1, Trunc, "", EntryBB);
Instruction *Add2 = BinaryOperator::CreateAdd(Mul1, Add1, "", EntryBB);
// FIXME: The size of this is arbitrary and doesn't seem to change the
// result, but SCEV will do quadratic work for these so a large number here
// will be extremely slow. We should revisit what and how this is testing
// SCEV.
for (int i = 0; i < 10; i++) {
Mul1 = BinaryOperator::CreateMul(Add2, Add1, "", EntryBB);
Add1 = Add2;
Add2 = BinaryOperator::CreateAdd(Mul1, Add1, "", EntryBB);
}
ReturnInst::Create(Context, nullptr, EntryBB);
ScalarEvolution SE = buildSE(*F);
EXPECT_NE(nullptr, SE.getSCEV(Mul1));
}
static Instruction &GetInstByName(Function &F, StringRef Name) {
for (auto &I : instructions(F))
if (I.getName() == Name)
return I;
llvm_unreachable("Could not find instructions!");
}
TEST_F(ScalarEvolutionsTest, SCEVNormalization) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(
"target datalayout = \"e-m:e-p:32:32-f64:32:64-f80:32-n8:16:32-S128\" "
" "
"@var_0 = external global i32, align 4"
"@var_1 = external global i32, align 4"
"@var_2 = external global i32, align 4"
" "
"declare i32 @unknown(i32, i32, i32)"
" "
"define void @f_1(i8* nocapture %arr, i32 %n, i32* %A, i32* %B) "
" local_unnamed_addr { "
"entry: "
" br label %loop.ph "
" "
"loop.ph: "
" br label %loop "
" "
"loop: "
" %iv0 = phi i32 [ %iv0.inc, %loop ], [ 0, %loop.ph ] "
" %iv1 = phi i32 [ %iv1.inc, %loop ], [ -2147483648, %loop.ph ] "
" %iv0.inc = add i32 %iv0, 1 "
" %iv1.inc = add i32 %iv1, 3 "
" br i1 undef, label %for.end.loopexit, label %loop "
" "
"for.end.loopexit: "
" ret void "
"} "
" "
"define void @f_2(i32 %a, i32 %b, i32 %c, i32 %d) "
" local_unnamed_addr { "
"entry: "
" br label %loop_0 "
" "
"loop_0: "
" br i1 undef, label %loop_0, label %loop_1 "
" "
"loop_1: "
" br i1 undef, label %loop_2, label %loop_1 "
" "
" "
"loop_2: "
" br i1 undef, label %end, label %loop_2 "
" "
"end: "
" ret void "
"} "
,
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "f_1", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I0 = GetInstByName(F, "iv0");
auto &I1 = *I0.getNextNode();
auto *S0 = cast<SCEVAddRecExpr>(SE.getSCEV(&I0));
PostIncLoopSet Loops;
Loops.insert(S0->getLoop());
auto *N0 = normalizeForPostIncUse(S0, Loops, SE);
auto *D0 = denormalizeForPostIncUse(N0, Loops, SE);
EXPECT_EQ(S0, D0) << *S0 << " " << *D0;
auto *S1 = cast<SCEVAddRecExpr>(SE.getSCEV(&I1));
Loops.clear();
Loops.insert(S1->getLoop());
auto *N1 = normalizeForPostIncUse(S1, Loops, SE);
auto *D1 = denormalizeForPostIncUse(N1, Loops, SE);
EXPECT_EQ(S1, D1) << *S1 << " " << *D1;
});
runWithSE(*M, "f_2", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto *L2 = *LI.begin();
auto *L1 = *std::next(LI.begin());
auto *L0 = *std::next(LI.begin(), 2);
auto GetAddRec = [&SE](const Loop *L, std::initializer_list<const SCEV *> Ops) {
SmallVector<const SCEV *, 4> OpsCopy(Ops);
return SE.getAddRecExpr(OpsCopy, L, SCEV::FlagAnyWrap);
};
auto GetAdd = [&SE](std::initializer_list<const SCEV *> Ops) {
SmallVector<const SCEV *, 4> OpsCopy(Ops);
return SE.getAddExpr(OpsCopy, SCEV::FlagAnyWrap);
};
// We first populate the AddRecs vector with a few "interesting" SCEV
// expressions, and then we go through the list and assert that each
// expression in it has an invertible normalization.
std::vector<const SCEV *> Exprs;
{
const SCEV *V0 = SE.getSCEV(&*F.arg_begin());
const SCEV *V1 = SE.getSCEV(&*std::next(F.arg_begin(), 1));
const SCEV *V2 = SE.getSCEV(&*std::next(F.arg_begin(), 2));
const SCEV *V3 = SE.getSCEV(&*std::next(F.arg_begin(), 3));
Exprs.push_back(GetAddRec(L0, {V0})); // 0
Exprs.push_back(GetAddRec(L0, {V0, V1})); // 1
Exprs.push_back(GetAddRec(L0, {V0, V1, V2})); // 2
Exprs.push_back(GetAddRec(L0, {V0, V1, V2, V3})); // 3
Exprs.push_back(
GetAddRec(L1, {Exprs[1], Exprs[2], Exprs[3], Exprs[0]})); // 4
Exprs.push_back(
GetAddRec(L1, {Exprs[1], Exprs[2], Exprs[0], Exprs[3]})); // 5
Exprs.push_back(
GetAddRec(L1, {Exprs[1], Exprs[3], Exprs[3], Exprs[1]})); // 6
Exprs.push_back(GetAdd({Exprs[6], Exprs[3], V2})); // 7
Exprs.push_back(
GetAddRec(L2, {Exprs[4], Exprs[3], Exprs[3], Exprs[5]})); // 8
Exprs.push_back(
GetAddRec(L2, {Exprs[4], Exprs[6], Exprs[7], Exprs[3], V0})); // 9
}
std::vector<PostIncLoopSet> LoopSets;
for (int i = 0; i < 8; i++) {
LoopSets.emplace_back();
if (i & 1)
LoopSets.back().insert(L0);
if (i & 2)
LoopSets.back().insert(L1);
if (i & 4)
LoopSets.back().insert(L2);
}
for (const auto &LoopSet : LoopSets)
for (auto *S : Exprs) {
{
auto *N = llvm::normalizeForPostIncUse(S, LoopSet, SE);
auto *D = llvm::denormalizeForPostIncUse(N, LoopSet, SE);
// Normalization and then denormalizing better give us back the same
// value.
EXPECT_EQ(S, D) << "S = " << *S << " D = " << *D << " N = " << *N;
}
{
auto *D = llvm::denormalizeForPostIncUse(S, LoopSet, SE);
auto *N = llvm::normalizeForPostIncUse(D, LoopSet, SE);
// Denormalization and then normalizing better give us back the same
// value.
EXPECT_EQ(S, N) << "S = " << *S << " N = " << *N;
}
}
});
}
// Expect the call of getZeroExtendExpr will not cost exponential time.
TEST_F(ScalarEvolutionsTest, SCEVZeroExtendExpr) {
LLVMContext C;
SMDiagnostic Err;
// Generate a function like below:
// define void @foo() {
// entry:
// br label %for.cond
//
// for.cond:
// %0 = phi i64 [ 100, %entry ], [ %dec, %for.inc ]
// %cmp = icmp sgt i64 %0, 90
// br i1 %cmp, label %for.inc, label %for.cond1
//
// for.inc:
// %dec = add nsw i64 %0, -1
// br label %for.cond
//
// for.cond1:
// %1 = phi i64 [ 100, %for.cond ], [ %dec5, %for.inc2 ]
// %cmp3 = icmp sgt i64 %1, 90
// br i1 %cmp3, label %for.inc2, label %for.cond4
//
// for.inc2:
// %dec5 = add nsw i64 %1, -1
// br label %for.cond1
//
// ......
//
// for.cond89:
// %19 = phi i64 [ 100, %for.cond84 ], [ %dec94, %for.inc92 ]
// %cmp93 = icmp sgt i64 %19, 90
// br i1 %cmp93, label %for.inc92, label %for.end
//
// for.inc92:
// %dec94 = add nsw i64 %19, -1
// br label %for.cond89
//
// for.end:
// %gep = getelementptr i8, i8* null, i64 %dec
// %gep6 = getelementptr i8, i8* %gep, i64 %dec5
// ......
// %gep95 = getelementptr i8, i8* %gep91, i64 %dec94
// ret void
// }
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context), {}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", M);
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
BasicBlock *CondBB = BasicBlock::Create(Context, "for.cond", F);
BasicBlock *EndBB = BasicBlock::Create(Context, "for.end", F);
BranchInst::Create(CondBB, EntryBB);
BasicBlock *PrevBB = EntryBB;
Type *I64Ty = Type::getInt64Ty(Context);
Type *I8Ty = Type::getInt8Ty(Context);
Type *I8PtrTy = Type::getInt8PtrTy(Context);
Value *Accum = Constant::getNullValue(I8PtrTy);
int Iters = 20;
for (int i = 0; i < Iters; i++) {
BasicBlock *IncBB = BasicBlock::Create(Context, "for.inc", F, EndBB);
auto *PN = PHINode::Create(I64Ty, 2, "", CondBB);
PN->addIncoming(ConstantInt::get(Context, APInt(64, 100)), PrevBB);
auto *Cmp = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_SGT, PN,
ConstantInt::get(Context, APInt(64, 90)), "cmp",
CondBB);
BasicBlock *NextBB;
if (i != Iters - 1)
NextBB = BasicBlock::Create(Context, "for.cond", F, EndBB);
else
NextBB = EndBB;
BranchInst::Create(IncBB, NextBB, Cmp, CondBB);
auto *Dec = BinaryOperator::CreateNSWAdd(
PN, ConstantInt::get(Context, APInt(64, -1)), "dec", IncBB);
PN->addIncoming(Dec, IncBB);
BranchInst::Create(CondBB, IncBB);
Accum = GetElementPtrInst::Create(I8Ty, Accum, PN, "gep", EndBB);
PrevBB = CondBB;
CondBB = NextBB;
}
ReturnInst::Create(Context, nullptr, EndBB);
ScalarEvolution SE = buildSE(*F);
const SCEV *S = SE.getSCEV(Accum);
Type *I128Ty = Type::getInt128Ty(Context);
SE.getZeroExtendExpr(S, I128Ty);
}
// Make sure that SCEV invalidates exit limits after invalidating the values it
// depends on when we forget a loop.
TEST_F(ScalarEvolutionsTest, SCEVExitLimitForgetLoop) {
/*
* Create the following code:
* func(i64 addrspace(10)* %arg)
* top:
* br label %L.ph
* L.ph:
* br label %L
* L:
* %phi = phi i64 [i64 0, %L.ph], [ %add, %L2 ]
* %add = add i64 %phi2, 1
* %cond = icmp slt i64 %add, 1000; then becomes 2000.
* br i1 %cond, label %post, label %L2
* post:
* ret void
*
*/
// Create a module with non-integral pointers in it's datalayout
Module NIM("nonintegral", Context);
std::string DataLayout = M.getDataLayoutStr();
if (!DataLayout.empty())
DataLayout += "-";
DataLayout += "ni:10";
NIM.setDataLayout(DataLayout);
Type *T_int64 = Type::getInt64Ty(Context);
Type *T_pint64 = T_int64->getPointerTo(10);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_pint64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", NIM);
BasicBlock *Top = BasicBlock::Create(Context, "top", F);
BasicBlock *LPh = BasicBlock::Create(Context, "L.ph", F);
BasicBlock *L = BasicBlock::Create(Context, "L", F);
BasicBlock *Post = BasicBlock::Create(Context, "post", F);
IRBuilder<> Builder(Top);
Builder.CreateBr(LPh);
Builder.SetInsertPoint(LPh);
Builder.CreateBr(L);
Builder.SetInsertPoint(L);
PHINode *Phi = Builder.CreatePHI(T_int64, 2);
auto *Add = cast<Instruction>(
Builder.CreateAdd(Phi, ConstantInt::get(T_int64, 1), "add"));
auto *Limit = ConstantInt::get(T_int64, 1000);
auto *Cond = cast<Instruction>(
Builder.CreateICmp(ICmpInst::ICMP_SLT, Add, Limit, "cond"));
auto *Br = cast<Instruction>(Builder.CreateCondBr(Cond, L, Post));
Phi->addIncoming(ConstantInt::get(T_int64, 0), LPh);
Phi->addIncoming(Add, L);
Builder.SetInsertPoint(Post);
Builder.CreateRetVoid();
ScalarEvolution SE = buildSE(*F);
auto *Loop = LI->getLoopFor(L);
const SCEV *EC = SE.getBackedgeTakenCount(Loop);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(EC));
EXPECT_TRUE(isa<SCEVConstant>(EC));
EXPECT_EQ(cast<SCEVConstant>(EC)->getAPInt().getLimitedValue(), 999u);
// The add recurrence {5,+,1} does not correspond to any PHI in the IR, and
// that is relevant to this test.
auto *Five = SE.getConstant(APInt(/*numBits=*/64, 5));
auto *AR =
SE.getAddRecExpr(Five, SE.getOne(T_int64), Loop, SCEV::FlagAnyWrap);
const SCEV *ARAtLoopExit = SE.getSCEVAtScope(AR, nullptr);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(ARAtLoopExit));
EXPECT_TRUE(isa<SCEVConstant>(ARAtLoopExit));
EXPECT_EQ(cast<SCEVConstant>(ARAtLoopExit)->getAPInt().getLimitedValue(),
1004u);
SE.forgetLoop(Loop);
Br->eraseFromParent();
Cond->eraseFromParent();
Builder.SetInsertPoint(L);
auto *NewCond = Builder.CreateICmp(
ICmpInst::ICMP_SLT, Add, ConstantInt::get(T_int64, 2000), "new.cond");
Builder.CreateCondBr(NewCond, L, Post);
const SCEV *NewEC = SE.getBackedgeTakenCount(Loop);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(NewEC));
EXPECT_TRUE(isa<SCEVConstant>(NewEC));
EXPECT_EQ(cast<SCEVConstant>(NewEC)->getAPInt().getLimitedValue(), 1999u);
const SCEV *NewARAtLoopExit = SE.getSCEVAtScope(AR, nullptr);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(NewARAtLoopExit));
EXPECT_TRUE(isa<SCEVConstant>(NewARAtLoopExit));
EXPECT_EQ(cast<SCEVConstant>(NewARAtLoopExit)->getAPInt().getLimitedValue(),
2004u);
}
// Make sure that SCEV invalidates exit limits after invalidating the values it
// depends on when we forget a value.
TEST_F(ScalarEvolutionsTest, SCEVExitLimitForgetValue) {
/*
* Create the following code:
* func(i64 addrspace(10)* %arg)
* top:
* br label %L.ph
* L.ph:
* %load = load i64 addrspace(10)* %arg
* br label %L
* L:
* %phi = phi i64 [i64 0, %L.ph], [ %add, %L2 ]
* %add = add i64 %phi2, 1
* %cond = icmp slt i64 %add, %load ; then becomes 2000.
* br i1 %cond, label %post, label %L2
* post:
* ret void
*
*/
// Create a module with non-integral pointers in it's datalayout
Module NIM("nonintegral", Context);
std::string DataLayout = M.getDataLayoutStr();
if (!DataLayout.empty())
DataLayout += "-";
DataLayout += "ni:10";
NIM.setDataLayout(DataLayout);
Type *T_int64 = Type::getInt64Ty(Context);
Type *T_pint64 = T_int64->getPointerTo(10);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_pint64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "foo", NIM);
Argument *Arg = &*F->arg_begin();
BasicBlock *Top = BasicBlock::Create(Context, "top", F);
BasicBlock *LPh = BasicBlock::Create(Context, "L.ph", F);
BasicBlock *L = BasicBlock::Create(Context, "L", F);
BasicBlock *Post = BasicBlock::Create(Context, "post", F);
IRBuilder<> Builder(Top);
Builder.CreateBr(LPh);
Builder.SetInsertPoint(LPh);
auto *Load = cast<Instruction>(Builder.CreateLoad(T_int64, Arg, "load"));
Builder.CreateBr(L);
Builder.SetInsertPoint(L);
PHINode *Phi = Builder.CreatePHI(T_int64, 2);
auto *Add = cast<Instruction>(
Builder.CreateAdd(Phi, ConstantInt::get(T_int64, 1), "add"));
auto *Cond = cast<Instruction>(
Builder.CreateICmp(ICmpInst::ICMP_SLT, Add, Load, "cond"));
auto *Br = cast<Instruction>(Builder.CreateCondBr(Cond, L, Post));
Phi->addIncoming(ConstantInt::get(T_int64, 0), LPh);
Phi->addIncoming(Add, L);
Builder.SetInsertPoint(Post);
Builder.CreateRetVoid();
ScalarEvolution SE = buildSE(*F);
auto *Loop = LI->getLoopFor(L);
const SCEV *EC = SE.getBackedgeTakenCount(Loop);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(EC));
EXPECT_FALSE(isa<SCEVConstant>(EC));
SE.forgetValue(Load);
Br->eraseFromParent();
Cond->eraseFromParent();
Load->eraseFromParent();
Builder.SetInsertPoint(L);
auto *NewCond = Builder.CreateICmp(
ICmpInst::ICMP_SLT, Add, ConstantInt::get(T_int64, 2000), "new.cond");
Builder.CreateCondBr(NewCond, L, Post);
const SCEV *NewEC = SE.getBackedgeTakenCount(Loop);
EXPECT_FALSE(isa<SCEVCouldNotCompute>(NewEC));
EXPECT_TRUE(isa<SCEVConstant>(NewEC));
EXPECT_EQ(cast<SCEVConstant>(NewEC)->getAPInt().getLimitedValue(), 1999u);
}
TEST_F(ScalarEvolutionsTest, SCEVAddRecFromPHIwithLargeConstants) {
// Reference: https://reviews.llvm.org/D37265
// Make sure that SCEV does not blow up when constructing an AddRec
// with predicates for a phi with the update pattern:
// (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum
// when either the initial value of the Phi or the InvariantAccum are
// constants that are too large to fit in an ix but are zero when truncated to
// ix.
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), std::vector<Type *>(), false);
Function *F =
Function::Create(FTy, Function::ExternalLinkage, "addrecphitest", M);
/*
Create IR:
entry:
br label %loop
loop:
%0 = phi i64 [-9223372036854775808, %entry], [%3, %loop]
%1 = shl i64 %0, 32
%2 = ashr exact i64 %1, 32
%3 = add i64 %2, -9223372036854775808
br i1 undef, label %exit, label %loop
exit:
ret void
*/
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
BasicBlock *LoopBB = BasicBlock::Create(Context, "loop", F);
BasicBlock *ExitBB = BasicBlock::Create(Context, "exit", F);
// entry:
BranchInst::Create(LoopBB, EntryBB);
// loop:
auto *MinInt64 =
ConstantInt::get(Context, APInt(64, 0x8000000000000000U, true));
auto *Int64_32 = ConstantInt::get(Context, APInt(64, 32));
auto *Br = BranchInst::Create(
LoopBB, ExitBB, UndefValue::get(Type::getInt1Ty(Context)), LoopBB);
auto *Phi = PHINode::Create(Type::getInt64Ty(Context), 2, "", Br);
auto *Shl = BinaryOperator::CreateShl(Phi, Int64_32, "", Br);
auto *AShr = BinaryOperator::CreateExactAShr(Shl, Int64_32, "", Br);
auto *Add = BinaryOperator::CreateAdd(AShr, MinInt64, "", Br);
Phi->addIncoming(MinInt64, EntryBB);
Phi->addIncoming(Add, LoopBB);
// exit:
ReturnInst::Create(Context, nullptr, ExitBB);
// Make sure that SCEV doesn't blow up
ScalarEvolution SE = buildSE(*F);
SCEVUnionPredicate Preds;
const SCEV *Expr = SE.getSCEV(Phi);
EXPECT_NE(nullptr, Expr);
EXPECT_TRUE(isa<SCEVUnknown>(Expr));
auto Result = SE.createAddRecFromPHIWithCasts(cast<SCEVUnknown>(Expr));
}
TEST_F(ScalarEvolutionsTest, SCEVAddRecFromPHIwithLargeConstantAccum) {
// Make sure that SCEV does not blow up when constructing an AddRec
// with predicates for a phi with the update pattern:
// (SExt/ZExt ix (Trunc iy (%SymbolicPHI) to ix) to iy) + InvariantAccum
// when the InvariantAccum is a constant that is too large to fit in an
// ix but are zero when truncated to ix, and the initial value of the
// phi is not a constant.
Type *Int32Ty = Type::getInt32Ty(Context);
SmallVector<Type *, 1> Types;
Types.push_back(Int32Ty);
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context), Types, false);
Function *F =
Function::Create(FTy, Function::ExternalLinkage, "addrecphitest", M);
/*
Create IR:
define @addrecphitest(i32)
entry:
br label %loop
loop:
%1 = phi i32 [%0, %entry], [%4, %loop]
%2 = shl i32 %1, 16
%3 = ashr exact i32 %2, 16
%4 = add i32 %3, -2147483648
br i1 undef, label %exit, label %loop
exit:
ret void
*/
BasicBlock *EntryBB = BasicBlock::Create(Context, "entry", F);
BasicBlock *LoopBB = BasicBlock::Create(Context, "loop", F);
BasicBlock *ExitBB = BasicBlock::Create(Context, "exit", F);
// entry:
BranchInst::Create(LoopBB, EntryBB);
// loop:
auto *MinInt32 = ConstantInt::get(Context, APInt(32, 0x80000000U, true));
auto *Int32_16 = ConstantInt::get(Context, APInt(32, 16));
auto *Br = BranchInst::Create(
LoopBB, ExitBB, UndefValue::get(Type::getInt1Ty(Context)), LoopBB);
auto *Phi = PHINode::Create(Int32Ty, 2, "", Br);
auto *Shl = BinaryOperator::CreateShl(Phi, Int32_16, "", Br);
auto *AShr = BinaryOperator::CreateExactAShr(Shl, Int32_16, "", Br);
auto *Add = BinaryOperator::CreateAdd(AShr, MinInt32, "", Br);
auto *Arg = &*(F->arg_begin());
Phi->addIncoming(Arg, EntryBB);
Phi->addIncoming(Add, LoopBB);
// exit:
ReturnInst::Create(Context, nullptr, ExitBB);
// Make sure that SCEV doesn't blow up
ScalarEvolution SE = buildSE(*F);
SCEVUnionPredicate Preds;
const SCEV *Expr = SE.getSCEV(Phi);
EXPECT_NE(nullptr, Expr);
EXPECT_TRUE(isa<SCEVUnknown>(Expr));
auto Result = SE.createAddRecFromPHIWithCasts(cast<SCEVUnknown>(Expr));
}
TEST_F(ScalarEvolutionsTest, SCEVFoldSumOfTruncs) {
// Verify that the following SCEV gets folded to a zero:
// (-1 * (trunc i64 (-1 * %0) to i32)) + (-1 * (trunc i64 %0 to i32)
Type *ArgTy = Type::getInt64Ty(Context);
Type *Int32Ty = Type::getInt32Ty(Context);
SmallVector<Type *, 1> Types;
Types.push_back(ArgTy);
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Context), Types, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "f", M);
BasicBlock *BB = BasicBlock::Create(Context, "entry", F);
ReturnInst::Create(Context, nullptr, BB);
ScalarEvolution SE = buildSE(*F);
auto *Arg = &*(F->arg_begin());
const auto *ArgSCEV = SE.getSCEV(Arg);
// Build the SCEV
const auto *A0 = SE.getNegativeSCEV(ArgSCEV);
const auto *A1 = SE.getTruncateExpr(A0, Int32Ty);
const auto *A = SE.getNegativeSCEV(A1);
const auto *B0 = SE.getTruncateExpr(ArgSCEV, Int32Ty);
const auto *B = SE.getNegativeSCEV(B0);
const auto *Expr = SE.getAddExpr(A, B);
// Verify that the SCEV was folded to 0
const auto *ZeroConst = SE.getConstant(Int32Ty, 0);
EXPECT_EQ(Expr, ZeroConst);
}
// Check logic of SCEV expression size computation.
TEST_F(ScalarEvolutionsTest, SCEVComputeExpressionSize) {
/*
* Create the following code:
* void func(i64 %a, i64 %b)
* entry:
* %s1 = add i64 %a, 1
* %s2 = udiv i64 %s1, %b
* br label %exit
* exit:
* ret
*/
// Create a module.
Module M("SCEVComputeExpressionSize", Context);
Type *T_int64 = Type::getInt64Ty(Context);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), { T_int64, T_int64 }, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "func", M);
Argument *A = &*F->arg_begin();
Argument *B = &*std::next(F->arg_begin());
ConstantInt *C = ConstantInt::get(Context, APInt(64, 1));
BasicBlock *Entry = BasicBlock::Create(Context, "entry", F);
BasicBlock *Exit = BasicBlock::Create(Context, "exit", F);
IRBuilder<> Builder(Entry);
auto *S1 = cast<Instruction>(Builder.CreateAdd(A, C, "s1"));
auto *S2 = cast<Instruction>(Builder.CreateUDiv(S1, B, "s2"));
Builder.CreateBr(Exit);
Builder.SetInsertPoint(Exit);
Builder.CreateRetVoid();
ScalarEvolution SE = buildSE(*F);
// Get S2 first to move it to cache.
const SCEV *AS = SE.getSCEV(A);
const SCEV *BS = SE.getSCEV(B);
const SCEV *CS = SE.getSCEV(C);
const SCEV *S1S = SE.getSCEV(S1);
const SCEV *S2S = SE.getSCEV(S2);
EXPECT_EQ(AS->getExpressionSize(), 1u);
EXPECT_EQ(BS->getExpressionSize(), 1u);
EXPECT_EQ(CS->getExpressionSize(), 1u);
EXPECT_EQ(S1S->getExpressionSize(), 3u);
EXPECT_EQ(S2S->getExpressionSize(), 5u);
}
TEST_F(ScalarEvolutionsTest, SCEVLoopDecIntrinsic) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(
"define void @foo(i32 %N) { "
"entry: "
" %cmp3 = icmp sgt i32 %N, 0 "
" br i1 %cmp3, label %for.body, label %for.cond.cleanup "
"for.cond.cleanup: "
" ret void "
"for.body: "
" %i.04 = phi i32 [ %inc, %for.body ], [ 100, %entry ] "
" %inc = call i32 @llvm.loop.decrement.reg.i32.i32.i32(i32 %i.04, i32 1) "
" %exitcond = icmp ne i32 %inc, 0 "
" br i1 %exitcond, label %for.cond.cleanup, label %for.body "
"} "
"declare i32 @llvm.loop.decrement.reg.i32.i32.i32(i32, i32) ",
Err, C);
ASSERT_TRUE(M && "Could not parse module?");
ASSERT_TRUE(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "foo", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto *ScevInc = SE.getSCEV(getInstructionByName(F, "inc"));
EXPECT_TRUE(isa<SCEVAddRecExpr>(ScevInc));
});
}
TEST_F(ScalarEvolutionsTest, SCEVComputeConstantDifference) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(
"define void @foo(i32 %sz, i32 %pp) { "
"entry: "
" %v0 = add i32 %pp, 0 "
" %v3 = add i32 %pp, 3 "
" br label %loop.body "
"loop.body: "
" %iv = phi i32 [ %iv.next, %loop.body ], [ 0, %entry ] "
" %xa = add nsw i32 %iv, %v0 "
" %yy = add nsw i32 %iv, %v3 "
" %xb = sub nsw i32 %yy, 3 "
" %iv.next = add nsw i32 %iv, 1 "
" %cmp = icmp sle i32 %iv.next, %sz "
" br i1 %cmp, label %loop.body, label %exit "
"exit: "
" ret void "
"} ",
Err, C);
ASSERT_TRUE(M && "Could not parse module?");
ASSERT_TRUE(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "foo", [](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto *ScevV0 = SE.getSCEV(getInstructionByName(F, "v0")); // %pp
auto *ScevV3 = SE.getSCEV(getInstructionByName(F, "v3")); // (3 + %pp)
auto *ScevIV = SE.getSCEV(getInstructionByName(F, "iv")); // {0,+,1}
auto *ScevXA = SE.getSCEV(getInstructionByName(F, "xa")); // {%pp,+,1}
auto *ScevYY = SE.getSCEV(getInstructionByName(F, "yy")); // {(3 + %pp),+,1}
auto *ScevXB = SE.getSCEV(getInstructionByName(F, "xb")); // {%pp,+,1}
auto *ScevIVNext = SE.getSCEV(getInstructionByName(F, "iv.next")); // {1,+,1}
auto diff = [&SE](const SCEV *LHS, const SCEV *RHS) -> Optional<int> {
auto ConstantDiffOrNone = computeConstantDifference(SE, LHS, RHS);
if (!ConstantDiffOrNone)
return None;
auto ExtDiff = ConstantDiffOrNone->getSExtValue();
int Diff = ExtDiff;
assert(Diff == ExtDiff && "Integer overflow");
return Diff;
};
EXPECT_EQ(diff(ScevV3, ScevV0), 3);
EXPECT_EQ(diff(ScevV0, ScevV3), -3);
EXPECT_EQ(diff(ScevV0, ScevV0), 0);
EXPECT_EQ(diff(ScevV3, ScevV3), 0);
EXPECT_EQ(diff(ScevIV, ScevIV), 0);
EXPECT_EQ(diff(ScevXA, ScevXB), 0);
EXPECT_EQ(diff(ScevXA, ScevYY), -3);
EXPECT_EQ(diff(ScevYY, ScevXB), 3);
EXPECT_EQ(diff(ScevIV, ScevIVNext), -1);
EXPECT_EQ(diff(ScevIVNext, ScevIV), 1);
EXPECT_EQ(diff(ScevIVNext, ScevIVNext), 0);
EXPECT_EQ(diff(ScevV0, ScevIV), None);
EXPECT_EQ(diff(ScevIVNext, ScevV3), None);
EXPECT_EQ(diff(ScevYY, ScevV3), None);
});
}
} // end namespace llvm
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