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llvm-mirror/unittests/Transforms/Utils/ScalarEvolutionExpanderTest.cpp
Eli Friedman e4884552df [ScalarEvolution] Fix pointer/int type handling converting select/phi to min/max. 
The old version of this code would blindly perform arithmetic without
paying attention to whether the types involved were pointers or
integers.  This could lead to weird expressions like negating a pointer.

Explicitly handle simple cases involving pointers, like "x < y ? x : y".
In all other cases, coerce the operands of the comparison to integer
types.  This avoids the weird cases, while handling most of the
interesting cases.

Differential Revision: https://reviews.llvm.org/D103660
2021-06-17 14:05:12 -07:00

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//=== ScalarEvolutionExpanderTest.cpp - ScalarEvolutionExpander 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/Transforms/Utils/ScalarEvolutionExpander.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.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/Module.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
namespace llvm {
using namespace PatternMatch;
// We use this fixture to ensure that we clean up ScalarEvolution before
// deleting the PassManager.
class ScalarEvolutionExpanderTest : 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;
ScalarEvolutionExpanderTest() : 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 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(ScalarEvolutionExpanderTest, ExpandPtrTypeSCEV) {
// It is to test the fix for PR30213. It exercises the branch in scev
// expansion when the value in ValueOffsetPair is a ptr and the offset
// is not divisible by the elem type size of value.
auto *I8Ty = Type::getInt8Ty(Context);
auto *I8PtrTy = Type::getInt8PtrTy(Context);
auto *I32Ty = Type::getInt32Ty(Context);
auto *I32PtrTy = Type::getInt32PtrTy(Context);
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);
ReturnInst::Create(Context, nullptr, ExitBB);
// loop: ; preds = %loop, %entry
// %alloca = alloca i32
// %gep0 = getelementptr i32, i32* %alloca, i32 1
// %bitcast1 = bitcast i32* %gep0 to i8*
// %gep1 = getelementptr i8, i8* %bitcast1, i32 1
// %gep2 = getelementptr i8, i8* undef, i32 1
// %cmp = icmp ult i8* undef, %bitcast1
// %select = select i1 %cmp, i8* %gep1, i8* %gep2
// %bitcast2 = bitcast i8* %select to i32*
// br i1 undef, label %loop, label %exit
const DataLayout &DL = F->getParent()->getDataLayout();
BranchInst *Br = BranchInst::Create(
LoopBB, ExitBB, UndefValue::get(Type::getInt1Ty(Context)), LoopBB);
AllocaInst *Alloca =
new AllocaInst(I32Ty, DL.getAllocaAddrSpace(), "alloca", Br);
ConstantInt *Ci32 = ConstantInt::get(Context, APInt(32, 1));
GetElementPtrInst *Gep0 =
GetElementPtrInst::Create(I32Ty, Alloca, Ci32, "gep0", Br);
CastInst *CastA =
CastInst::CreateBitOrPointerCast(Gep0, I8PtrTy, "bitcast1", Br);
GetElementPtrInst *Gep1 =
GetElementPtrInst::Create(I8Ty, CastA, Ci32, "gep1", Br);
GetElementPtrInst *Gep2 = GetElementPtrInst::Create(
I8Ty, UndefValue::get(I8PtrTy), Ci32, "gep2", Br);
CmpInst *Cmp = CmpInst::Create(Instruction::ICmp, CmpInst::ICMP_ULT,
UndefValue::get(I8PtrTy), CastA, "cmp", Br);
SelectInst *Sel = SelectInst::Create(Cmp, Gep1, Gep2, "select", Br);
CastInst *CastB =
CastInst::CreateBitOrPointerCast(Sel, I32PtrTy, "bitcast2", Br);
ScalarEvolution SE = buildSE(*F);
auto *S = SE.getSCEV(CastB);
EXPECT_TRUE(isa<SCEVUnknown>(S));
}
// Make sure that SCEV doesn't introduce illegal ptrtoint/inttoptr instructions
TEST_F(ScalarEvolutionExpanderTest, SCEVZeroExtendExprNonIntegral) {
/*
* 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
* br i1 undef, label %post, label %L2
* post:
* %gepbase = getelementptr i64 addrspace(10)* %arg, i64 1
* #= %gep = getelementptr i64 addrspace(10)* %gepbase, i64 %add =#
* ret void
*
* We will create the appropriate SCEV expression for %gep and expand it,
* then check that no inttoptr/ptrtoint instructions got inserted.
*/
// 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_int1 = Type::getInt1Ty(Context);
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);
Builder.CreateBr(L);
Builder.SetInsertPoint(L);
PHINode *Phi = Builder.CreatePHI(T_int64, 2);
Value *Add = Builder.CreateAdd(Phi, ConstantInt::get(T_int64, 1), "add");
Builder.CreateCondBr(UndefValue::get(T_int1), L, Post);
Phi->addIncoming(ConstantInt::get(T_int64, 0), LPh);
Phi->addIncoming(Add, L);
Builder.SetInsertPoint(Post);
Value *GepBase =
Builder.CreateGEP(T_int64, Arg, ConstantInt::get(T_int64, 1));
Instruction *Ret = Builder.CreateRetVoid();
ScalarEvolution SE = buildSE(*F);
auto *AddRec =
SE.getAddRecExpr(SE.getUnknown(GepBase), SE.getConstant(T_int64, 1),
LI->getLoopFor(L), SCEV::FlagNUW);
SCEVExpander Exp(SE, NIM.getDataLayout(), "expander");
Exp.disableCanonicalMode();
Exp.expandCodeFor(AddRec, T_pint64, Ret);
// Make sure none of the instructions inserted were inttoptr/ptrtoint.
// The verifier will check this.
EXPECT_FALSE(verifyFunction(*F, &errs()));
}
// Check that we can correctly identify the points at which the SCEV of the
// AddRec can be expanded.
TEST_F(ScalarEvolutionExpanderTest, SCEVExpanderIsSafeToExpandAt) {
/*
* 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"));
Builder.CreateCondBr(Cond, L, Post);
Phi->addIncoming(ConstantInt::get(T_int64, 0), LPh);
Phi->addIncoming(Add, L);
Builder.SetInsertPoint(Post);
Instruction *Ret = Builder.CreateRetVoid();
ScalarEvolution SE = buildSE(*F);
const SCEV *S = SE.getSCEV(Phi);
EXPECT_TRUE(isa<SCEVAddRecExpr>(S));
const SCEVAddRecExpr *AR = cast<SCEVAddRecExpr>(S);
EXPECT_TRUE(AR->isAffine());
EXPECT_FALSE(isSafeToExpandAt(AR, Top->getTerminator(), SE));
EXPECT_FALSE(isSafeToExpandAt(AR, LPh->getTerminator(), SE));
EXPECT_TRUE(isSafeToExpandAt(AR, L->getTerminator(), SE));
EXPECT_TRUE(isSafeToExpandAt(AR, Post->getTerminator(), SE));
EXPECT_TRUE(LI->getLoopFor(L)->isLCSSAForm(*DT));
SCEVExpander Exp(SE, M.getDataLayout(), "expander");
Exp.expandCodeFor(SE.getSCEV(Add), nullptr, Ret);
EXPECT_TRUE(LI->getLoopFor(L)->isLCSSAForm(*DT));
}
// Check that SCEV expander does not use the nuw instruction
// for expansion.
TEST_F(ScalarEvolutionExpanderTest, SCEVExpanderNUW) {
/*
* Create the following code:
* func(i64 %a)
* entry:
* br false, label %exit, label %body
* body:
* %s1 = add i64 %a, -1
* br label %exit
* exit:
* %s = add nuw i64 %a, -1
* ret %s
*/
// Create a module.
Module M("SCEVExpanderNUW", Context);
Type *T_int64 = Type::getInt64Ty(Context);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_int64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "func", M);
Argument *Arg = &*F->arg_begin();
ConstantInt *C = ConstantInt::get(Context, APInt(64, -1));
BasicBlock *Entry = BasicBlock::Create(Context, "entry", F);
BasicBlock *Body = BasicBlock::Create(Context, "body", F);
BasicBlock *Exit = BasicBlock::Create(Context, "exit", F);
IRBuilder<> Builder(Entry);
ConstantInt *Cond = ConstantInt::get(Context, APInt(1, 0));
Builder.CreateCondBr(Cond, Exit, Body);
Builder.SetInsertPoint(Body);
auto *S1 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
Builder.CreateBr(Exit);
Builder.SetInsertPoint(Exit);
auto *S2 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
S2->setHasNoUnsignedWrap(true);
auto *R = cast<Instruction>(Builder.CreateRetVoid());
ScalarEvolution SE = buildSE(*F);
const SCEV *S = SE.getSCEV(S1);
EXPECT_TRUE(isa<SCEVAddExpr>(S));
SCEVExpander Exp(SE, M.getDataLayout(), "expander");
auto *I = cast<Instruction>(Exp.expandCodeFor(S, nullptr, R));
EXPECT_FALSE(I->hasNoUnsignedWrap());
}
// Check that SCEV expander does not use the nsw instruction
// for expansion.
TEST_F(ScalarEvolutionExpanderTest, SCEVExpanderNSW) {
/*
* Create the following code:
* func(i64 %a)
* entry:
* br false, label %exit, label %body
* body:
* %s1 = add i64 %a, -1
* br label %exit
* exit:
* %s = add nsw i64 %a, -1
* ret %s
*/
// Create a module.
Module M("SCEVExpanderNSW", Context);
Type *T_int64 = Type::getInt64Ty(Context);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_int64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "func", M);
Argument *Arg = &*F->arg_begin();
ConstantInt *C = ConstantInt::get(Context, APInt(64, -1));
BasicBlock *Entry = BasicBlock::Create(Context, "entry", F);
BasicBlock *Body = BasicBlock::Create(Context, "body", F);
BasicBlock *Exit = BasicBlock::Create(Context, "exit", F);
IRBuilder<> Builder(Entry);
ConstantInt *Cond = ConstantInt::get(Context, APInt(1, 0));
Builder.CreateCondBr(Cond, Exit, Body);
Builder.SetInsertPoint(Body);
auto *S1 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
Builder.CreateBr(Exit);
Builder.SetInsertPoint(Exit);
auto *S2 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
S2->setHasNoSignedWrap(true);
auto *R = cast<Instruction>(Builder.CreateRetVoid());
ScalarEvolution SE = buildSE(*F);
const SCEV *S = SE.getSCEV(S1);
EXPECT_TRUE(isa<SCEVAddExpr>(S));
SCEVExpander Exp(SE, M.getDataLayout(), "expander");
auto *I = cast<Instruction>(Exp.expandCodeFor(S, nullptr, R));
EXPECT_FALSE(I->hasNoSignedWrap());
}
// Check that SCEV does not save the SCEV -> V
// mapping of SCEV differ from V in NUW flag.
TEST_F(ScalarEvolutionExpanderTest, SCEVCacheNUW) {
/*
* Create the following code:
* func(i64 %a)
* entry:
* %s1 = add i64 %a, -1
* %s2 = add nuw i64 %a, -1
* br label %exit
* exit:
* ret %s
*/
// Create a module.
Module M("SCEVCacheNUW", Context);
Type *T_int64 = Type::getInt64Ty(Context);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_int64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "func", M);
Argument *Arg = &*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(Arg, C, "add"));
auto *S2 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
S2->setHasNoUnsignedWrap(true);
Builder.CreateBr(Exit);
Builder.SetInsertPoint(Exit);
auto *R = cast<Instruction>(Builder.CreateRetVoid());
ScalarEvolution SE = buildSE(*F);
// Get S2 first to move it to cache.
const SCEV *SC2 = SE.getSCEV(S2);
EXPECT_TRUE(isa<SCEVAddExpr>(SC2));
// Now get S1.
const SCEV *SC1 = SE.getSCEV(S1);
EXPECT_TRUE(isa<SCEVAddExpr>(SC1));
// Expand for S1, it should use S1 not S2 in spite S2
// first in the cache.
SCEVExpander Exp(SE, M.getDataLayout(), "expander");
auto *I = cast<Instruction>(Exp.expandCodeFor(SC1, nullptr, R));
EXPECT_FALSE(I->hasNoUnsignedWrap());
}
// Check that SCEV does not save the SCEV -> V
// mapping of SCEV differ from V in NSW flag.
TEST_F(ScalarEvolutionExpanderTest, SCEVCacheNSW) {
/*
* Create the following code:
* func(i64 %a)
* entry:
* %s1 = add i64 %a, -1
* %s2 = add nsw i64 %a, -1
* br label %exit
* exit:
* ret %s
*/
// Create a module.
Module M("SCEVCacheNUW", Context);
Type *T_int64 = Type::getInt64Ty(Context);
FunctionType *FTy =
FunctionType::get(Type::getVoidTy(Context), {T_int64}, false);
Function *F = Function::Create(FTy, Function::ExternalLinkage, "func", M);
Argument *Arg = &*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(Arg, C, "add"));
auto *S2 = cast<Instruction>(Builder.CreateAdd(Arg, C, "add"));
S2->setHasNoSignedWrap(true);
Builder.CreateBr(Exit);
Builder.SetInsertPoint(Exit);
auto *R = cast<Instruction>(Builder.CreateRetVoid());
ScalarEvolution SE = buildSE(*F);
// Get S2 first to move it to cache.
const SCEV *SC2 = SE.getSCEV(S2);
EXPECT_TRUE(isa<SCEVAddExpr>(SC2));
// Now get S1.
const SCEV *SC1 = SE.getSCEV(S1);
EXPECT_TRUE(isa<SCEVAddExpr>(SC1));
// Expand for S1, it should use S1 not S2 in spite S2
// first in the cache.
SCEVExpander Exp(SE, M.getDataLayout(), "expander");
auto *I = cast<Instruction>(Exp.expandCodeFor(SC1, nullptr, R));
EXPECT_FALSE(I->hasNoSignedWrap());
}
TEST_F(ScalarEvolutionExpanderTest, SCEVExpandInsertCanonicalIV) {
LLVMContext C;
SMDiagnostic Err;
// Expand the addrec produced by GetAddRec into a loop without a canonical IV.
// SCEVExpander will insert one.
auto TestNoCanonicalIV =
[&](std::function<const SCEV *(ScalarEvolution & SE, Loop * L)>
GetAddRec) {
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(
*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto *Loop = LI.getLoopFor(I.getParent());
EXPECT_FALSE(Loop->getCanonicalInductionVariable());
auto *AR = GetAddRec(SE, Loop);
unsigned ExpectedCanonicalIVWidth =
SE.getTypeSizeInBits(AR->getType());
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Exp.expandCodeFor(AR, nullptr, InsertAt);
PHINode *CanonicalIV = Loop->getCanonicalInductionVariable();
unsigned CanonicalIVBitWidth =
cast<IntegerType>(CanonicalIV->getType())->getBitWidth();
EXPECT_EQ(CanonicalIVBitWidth, ExpectedCanonicalIVWidth);
});
};
// Expand the addrec produced by GetAddRec into a loop with a canonical IV
// which is narrower than addrec type.
// SCEVExpander will insert a canonical IV of a wider type to expand the
// addrec.
auto TestNarrowCanonicalIV = [&](std::function<const SCEV *(
ScalarEvolution & SE, Loop * L)>
GetAddRec) {
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %canonical.iv = phi i8 [ 0, %entry ], [ %canonical.iv.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %canonical.iv.inc = add i8 %canonical.iv, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto *LoopHeaderBB = I.getParent();
auto *Loop = LI.getLoopFor(LoopHeaderBB);
PHINode *CanonicalIV = Loop->getCanonicalInductionVariable();
EXPECT_EQ(CanonicalIV, &GetInstByName(F, "canonical.iv"));
auto *AR = GetAddRec(SE, Loop);
unsigned ExpectedCanonicalIVWidth = SE.getTypeSizeInBits(AR->getType());
unsigned CanonicalIVBitWidth =
cast<IntegerType>(CanonicalIV->getType())->getBitWidth();
EXPECT_LT(CanonicalIVBitWidth, ExpectedCanonicalIVWidth);
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Exp.expandCodeFor(AR, nullptr, InsertAt);
// Loop over all of the PHI nodes, looking for the new canonical indvar.
PHINode *NewCanonicalIV = nullptr;
for (BasicBlock::iterator i = LoopHeaderBB->begin(); isa<PHINode>(i);
++i) {
PHINode *PN = cast<PHINode>(i);
if (PN == &I || PN == CanonicalIV)
continue;
// We expect that the only PHI added is the new canonical IV
EXPECT_FALSE(NewCanonicalIV);
NewCanonicalIV = PN;
}
// Check that NewCanonicalIV is a canonical IV, i.e {0,+,1}
BasicBlock *Incoming = nullptr, *Backedge = nullptr;
EXPECT_TRUE(Loop->getIncomingAndBackEdge(Incoming, Backedge));
auto *Start = NewCanonicalIV->getIncomingValueForBlock(Incoming);
EXPECT_TRUE(isa<ConstantInt>(Start));
EXPECT_TRUE(dyn_cast<ConstantInt>(Start)->isZero());
auto *Next = NewCanonicalIV->getIncomingValueForBlock(Backedge);
EXPECT_TRUE(isa<BinaryOperator>(Next));
auto *NextBinOp = dyn_cast<BinaryOperator>(Next);
EXPECT_EQ(NextBinOp->getOpcode(), Instruction::Add);
EXPECT_EQ(NextBinOp->getOperand(0), NewCanonicalIV);
auto *Step = NextBinOp->getOperand(1);
EXPECT_TRUE(isa<ConstantInt>(Step));
EXPECT_TRUE(dyn_cast<ConstantInt>(Step)->isOne());
unsigned NewCanonicalIVBitWidth =
cast<IntegerType>(NewCanonicalIV->getType())->getBitWidth();
EXPECT_EQ(NewCanonicalIVBitWidth, ExpectedCanonicalIVWidth);
});
};
// Expand the addrec produced by GetAddRec into a loop with a canonical IV
// of addrec width.
// To expand the addrec SCEVExpander should use the existing canonical IV.
auto TestMatchingCanonicalIV =
[&](std::function<const SCEV *(ScalarEvolution & SE, Loop * L)> GetAddRec,
unsigned ARBitWidth) {
auto ARBitWidthTypeStr = "i" + std::to_string(ARBitWidth);
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %canonical.iv = phi " +
ARBitWidthTypeStr +
" [ 0, %entry ], [ %canonical.iv.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %canonical.iv.inc = add " +
ARBitWidthTypeStr +
" %canonical.iv, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(
*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto &CanonicalIV = GetInstByName(F, "canonical.iv");
auto *LoopHeaderBB = I.getParent();
auto *Loop = LI.getLoopFor(LoopHeaderBB);
EXPECT_EQ(&CanonicalIV, Loop->getCanonicalInductionVariable());
unsigned CanonicalIVBitWidth =
cast<IntegerType>(CanonicalIV.getType())->getBitWidth();
auto *AR = GetAddRec(SE, Loop);
EXPECT_EQ(ARBitWidth, SE.getTypeSizeInBits(AR->getType()));
EXPECT_EQ(CanonicalIVBitWidth, ARBitWidth);
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Exp.expandCodeFor(AR, nullptr, InsertAt);
// Loop over all of the PHI nodes, looking if a new canonical
// indvar was introduced.
PHINode *NewCanonicalIV = nullptr;
for (BasicBlock::iterator i = LoopHeaderBB->begin();
isa<PHINode>(i); ++i) {
PHINode *PN = cast<PHINode>(i);
if (PN == &I || PN == &CanonicalIV)
continue;
NewCanonicalIV = PN;
}
EXPECT_FALSE(NewCanonicalIV);
});
};
unsigned ARBitWidth = 16;
Type *ARType = IntegerType::get(C, ARBitWidth);
// Expand {5,+,1}
auto GetAR2 = [&](ScalarEvolution &SE, Loop *L) -> const SCEV * {
return SE.getAddRecExpr(SE.getConstant(APInt(ARBitWidth, 5)),
SE.getOne(ARType), L, SCEV::FlagAnyWrap);
};
TestNoCanonicalIV(GetAR2);
TestNarrowCanonicalIV(GetAR2);
TestMatchingCanonicalIV(GetAR2, ARBitWidth);
}
TEST_F(ScalarEvolutionExpanderTest, SCEVExpanderShlNSW) {
auto checkOneCase = [this](std::string &&str) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyString(str, Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
Function *F = M->getFunction("f");
ASSERT_NE(F, nullptr) << "Could not find function 'f'";
BasicBlock &Entry = F->getEntryBlock();
LoadInst *Load = cast<LoadInst>(&Entry.front());
BinaryOperator *And = cast<BinaryOperator>(*Load->user_begin());
ScalarEvolution SE = buildSE(*F);
const SCEV *AndSCEV = SE.getSCEV(And);
EXPECT_TRUE(isa<SCEVMulExpr>(AndSCEV));
EXPECT_TRUE(cast<SCEVMulExpr>(AndSCEV)->hasNoSignedWrap());
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *I = cast<Instruction>(Exp.expandCodeFor(AndSCEV, nullptr, And));
EXPECT_EQ(I->getOpcode(), Instruction::Shl);
EXPECT_FALSE(I->hasNoSignedWrap());
};
checkOneCase("define void @f(i16* %arrayidx) { "
" %1 = load i16, i16* %arrayidx "
" %2 = and i16 %1, -32768 "
" ret void "
"} ");
checkOneCase("define void @f(i8* %arrayidx) { "
" %1 = load i8, i8* %arrayidx "
" %2 = and i8 %1, -128 "
" ret void "
"} ");
}
// Test expansion of nested addrecs in CanonicalMode.
// Expanding nested addrecs in canonical mode requiers a canonical IV of a
// type wider than the type of the addrec itself. Currently, SCEVExpander
// just falls back to literal mode for nested addrecs.
TEST_F(ScalarEvolutionExpanderTest, SCEVExpandNonAffineAddRec) {
LLVMContext C;
SMDiagnostic Err;
// Expand the addrec produced by GetAddRec into a loop without a canonical IV.
auto TestNoCanonicalIV =
[&](std::function<const SCEVAddRecExpr *(ScalarEvolution & SE, Loop * L)>
GetAddRec) {
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "test",
[&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto *Loop = LI.getLoopFor(I.getParent());
EXPECT_FALSE(Loop->getCanonicalInductionVariable());
auto *AR = GetAddRec(SE, Loop);
EXPECT_FALSE(AR->isAffine());
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Value *V = Exp.expandCodeFor(AR, nullptr, InsertAt);
auto *ExpandedAR = SE.getSCEV(V);
// Check that the expansion happened literally.
EXPECT_EQ(AR, ExpandedAR);
});
};
// Expand the addrec produced by GetAddRec into a loop with a canonical IV
// which is narrower than addrec type.
auto TestNarrowCanonicalIV = [&](std::function<const SCEVAddRecExpr *(
ScalarEvolution & SE, Loop * L)>
GetAddRec) {
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %canonical.iv = phi i8 [ 0, %entry ], [ %canonical.iv.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %canonical.iv.inc = add i8 %canonical.iv, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto *LoopHeaderBB = I.getParent();
auto *Loop = LI.getLoopFor(LoopHeaderBB);
PHINode *CanonicalIV = Loop->getCanonicalInductionVariable();
EXPECT_EQ(CanonicalIV, &GetInstByName(F, "canonical.iv"));
auto *AR = GetAddRec(SE, Loop);
EXPECT_FALSE(AR->isAffine());
unsigned ExpectedCanonicalIVWidth = SE.getTypeSizeInBits(AR->getType());
unsigned CanonicalIVBitWidth =
cast<IntegerType>(CanonicalIV->getType())->getBitWidth();
EXPECT_LT(CanonicalIVBitWidth, ExpectedCanonicalIVWidth);
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Value *V = Exp.expandCodeFor(AR, nullptr, InsertAt);
auto *ExpandedAR = SE.getSCEV(V);
// Check that the expansion happened literally.
EXPECT_EQ(AR, ExpandedAR);
});
};
// Expand the addrec produced by GetAddRec into a loop with a canonical IV
// of addrec width.
auto TestMatchingCanonicalIV =
[&](std::function<const SCEVAddRecExpr *(ScalarEvolution & SE, Loop * L)>
GetAddRec,
unsigned ARBitWidth) {
auto ARBitWidthTypeStr = "i" + std::to_string(ARBitWidth);
std::unique_ptr<Module> M = parseAssemblyString(
"define i32 @test(i32 %limit) { "
"entry: "
" br label %loop "
"loop: "
" %i = phi i32 [ 1, %entry ], [ %i.inc, %loop ] "
" %canonical.iv = phi " +
ARBitWidthTypeStr +
" [ 0, %entry ], [ %canonical.iv.inc, %loop ] "
" %i.inc = add nsw i32 %i, 1 "
" %canonical.iv.inc = add " +
ARBitWidthTypeStr +
" %canonical.iv, 1 "
" %cont = icmp slt i32 %i.inc, %limit "
" br i1 %cont, label %loop, label %exit "
"exit: "
" ret i32 %i.inc "
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(
*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "i");
auto &CanonicalIV = GetInstByName(F, "canonical.iv");
auto *LoopHeaderBB = I.getParent();
auto *Loop = LI.getLoopFor(LoopHeaderBB);
EXPECT_EQ(&CanonicalIV, Loop->getCanonicalInductionVariable());
unsigned CanonicalIVBitWidth =
cast<IntegerType>(CanonicalIV.getType())->getBitWidth();
auto *AR = GetAddRec(SE, Loop);
EXPECT_FALSE(AR->isAffine());
EXPECT_EQ(ARBitWidth, SE.getTypeSizeInBits(AR->getType()));
EXPECT_EQ(CanonicalIVBitWidth, ARBitWidth);
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
auto *InsertAt = I.getNextNode();
Value *V = Exp.expandCodeFor(AR, nullptr, InsertAt);
auto *ExpandedAR = SE.getSCEV(V);
// Check that the expansion happened literally.
EXPECT_EQ(AR, ExpandedAR);
});
};
unsigned ARBitWidth = 16;
Type *ARType = IntegerType::get(C, ARBitWidth);
// Expand {5,+,1,+,1}
auto GetAR3 = [&](ScalarEvolution &SE, Loop *L) -> const SCEVAddRecExpr * {
SmallVector<const SCEV *, 3> Ops = {SE.getConstant(APInt(ARBitWidth, 5)),
SE.getOne(ARType), SE.getOne(ARType)};
return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, L, SCEV::FlagAnyWrap));
};
TestNoCanonicalIV(GetAR3);
TestNarrowCanonicalIV(GetAR3);
TestMatchingCanonicalIV(GetAR3, ARBitWidth);
// Expand {5,+,1,+,1,+,1}
auto GetAR4 = [&](ScalarEvolution &SE, Loop *L) -> const SCEVAddRecExpr * {
SmallVector<const SCEV *, 4> Ops = {SE.getConstant(APInt(ARBitWidth, 5)),
SE.getOne(ARType), SE.getOne(ARType),
SE.getOne(ARType)};
return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, L, SCEV::FlagAnyWrap));
};
TestNoCanonicalIV(GetAR4);
TestNarrowCanonicalIV(GetAR4);
TestMatchingCanonicalIV(GetAR4, ARBitWidth);
// Expand {5,+,1,+,1,+,1,+,1}
auto GetAR5 = [&](ScalarEvolution &SE, Loop *L) -> const SCEVAddRecExpr * {
SmallVector<const SCEV *, 5> Ops = {SE.getConstant(APInt(ARBitWidth, 5)),
SE.getOne(ARType), SE.getOne(ARType),
SE.getOne(ARType), SE.getOne(ARType)};
return cast<SCEVAddRecExpr>(SE.getAddRecExpr(Ops, L, SCEV::FlagAnyWrap));
};
TestNoCanonicalIV(GetAR5);
TestNarrowCanonicalIV(GetAR5);
TestMatchingCanonicalIV(GetAR5, ARBitWidth);
}
TEST_F(ScalarEvolutionExpanderTest, ExpandNonIntegralPtrWithNullBase) {
LLVMContext C;
SMDiagnostic Err;
std::unique_ptr<Module> M =
parseAssemblyString("target datalayout = "
"\"e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:"
"128-n8:16:32:64-S128-ni:1-p2:32:8:8:32-ni:2\""
"define float addrspace(1)* @test(i64 %offset) { "
" %ptr = getelementptr inbounds float, float "
"addrspace(1)* null, i64 %offset"
" ret float addrspace(1)* %ptr"
"}",
Err, C);
assert(M && "Could not parse module?");
assert(!verifyModule(*M) && "Must have been well formed!");
runWithSE(*M, "test", [&](Function &F, LoopInfo &LI, ScalarEvolution &SE) {
auto &I = GetInstByName(F, "ptr");
auto PtrPlus1 =
SE.getAddExpr(SE.getSCEV(&I), SE.getConstant(I.getType(), 1));
SCEVExpander Exp(SE, M->getDataLayout(), "expander");
Value *V = Exp.expandCodeFor(PtrPlus1, I.getType(), &I);
I.replaceAllUsesWith(V);
// Check that the expander created:
// define float addrspace(1)* @test(i64 %off) {
// %scevgep = getelementptr float, float addrspace(1)* null, i64 %off
// %scevgep1 = bitcast float addrspace(1)* %scevgep to i8 addrspace(1)*
// %uglygep = getelementptr i8, i8 addrspace(1)* %scevgep1, i64 1
// %uglygep2 = bitcast i8 addrspace(1)* %uglygep to float addrspace(1)*
// %ptr = getelementptr inbounds float, float addrspace(1)* null, i64 %off
// ret float addrspace(1)* %uglygep2
// }
auto *Cast = dyn_cast<BitCastInst>(V);
EXPECT_TRUE(Cast);
EXPECT_EQ(Cast->getType(), I.getType());
auto *GEP = dyn_cast<GetElementPtrInst>(Cast->getOperand(0));
EXPECT_TRUE(GEP);
EXPECT_TRUE(match(GEP->getOperand(1), m_SpecificInt(1)));
auto *Cast1 = dyn_cast<BitCastInst>(GEP->getPointerOperand());
EXPECT_TRUE(Cast1);
auto *GEP1 = dyn_cast<GetElementPtrInst>(Cast1->getOperand(0));
EXPECT_TRUE(GEP1);
EXPECT_TRUE(cast<Constant>(GEP1->getPointerOperand())->isNullValue());
EXPECT_EQ(GEP1->getOperand(1), &*F.arg_begin());
EXPECT_EQ(cast<PointerType>(GEP1->getPointerOperand()->getType())
->getAddressSpace(),
cast<PointerType>(I.getType())->getAddressSpace());
EXPECT_FALSE(verifyFunction(F, &errs()));
});
}
} // end namespace llvm
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