[Guards] Introduce loop-predication pass

This patch introduces guard based loop predication optimization. The new LoopPredication pass tries to convert loop variant range checks to loop invariant by widening checks across loop iterations. For example, it will convert

  for (i = 0; i < n; i++) {
    guard(i < len);
    ...
  }

to

  for (i = 0; i < n; i++) {
    guard(n - 1 < len);
    ...
  }

After this transformation the condition of the guard is loop invariant, so loop-unswitch can later unswitch the loop by this condition which basically predicates the loop by the widened condition:

  if (n - 1 < len)
    for (i = 0; i < n; i++) {
      ...
    } 
  else
    deoptimize

This patch relies on an NFC change to make ScalarEvolution::isMonotonicPredicate public (revision 293062).

Reviewed By: sanjoy

Differential Revision: https://reviews.llvm.org/D29034

llvm-svn: 293064
This commit is contained in:
Artur Pilipenko 2017-01-25 16:00:44 +00:00
parent 072e70b365
commit 8fb3d57e67
12 changed files with 1120 additions and 0 deletions

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@ -199,6 +199,7 @@ void initializeLoopInstSimplifyLegacyPassPass(PassRegistry&);
void initializeLoopInterchangePass(PassRegistry &);
void initializeLoopLoadEliminationPass(PassRegistry&);
void initializeLoopPassPass(PassRegistry&);
void initializeLoopPredicationLegacyPassPass(PassRegistry&);
void initializeLoopRerollPass(PassRegistry&);
void initializeLoopRotateLegacyPassPass(PassRegistry&);
void initializeLoopSimplifyCFGLegacyPassPass(PassRegistry&);

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@ -116,6 +116,7 @@ namespace {
(void) llvm::createLazyValueInfoPass();
(void) llvm::createLoopExtractorPass();
(void) llvm::createLoopInterchangePass();
(void) llvm::createLoopPredicationPass();
(void) llvm::createLoopSimplifyPass();
(void) llvm::createLoopSimplifyCFGPass();
(void) llvm::createLoopStrengthReducePass();

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@ -145,6 +145,12 @@ Pass *createLICMPass();
//
Pass *createLoopSinkPass();
//===----------------------------------------------------------------------===//
//
// LoopPredication - This pass does loop predication on guards.
//
Pass *createLoopPredicationPass();
//===----------------------------------------------------------------------===//
//
// LoopInterchange - This pass interchanges loops to provide a more

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@ -0,0 +1,32 @@
//===- LoopPredication.h - Guard based loop predication pass ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass tries to convert loop variant range checks to loop invariant by
// widening checks across loop iterations.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_SCALAR_LOOPPREDICATION_H
#define LLVM_TRANSFORMS_SCALAR_LOOPPREDICATION_H
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Transforms/Scalar/LoopPassManager.h"
namespace llvm {
/// Performs Loop Predication Pass.
class LoopPredicationPass : public PassInfoMixin<LoopPredicationPass> {
public:
PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR, LPMUpdater &U);
};
} // end namespace llvm
#endif // LLVM_TRANSFORMS_SCALAR_LOOPPREDICATION_H

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@ -105,6 +105,7 @@
#include "llvm/Transforms/Scalar/LoopIdiomRecognize.h"
#include "llvm/Transforms/Scalar/LoopInstSimplify.h"
#include "llvm/Transforms/Scalar/LoopPassManager.h"
#include "llvm/Transforms/Scalar/LoopPredication.h"
#include "llvm/Transforms/Scalar/LoopRotation.h"
#include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
#include "llvm/Transforms/Scalar/LoopSink.h"

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@ -227,4 +227,5 @@ LOOP_PASS("indvars", IndVarSimplifyPass())
LOOP_PASS("unroll", LoopUnrollPass())
LOOP_PASS("print-access-info", LoopAccessInfoPrinterPass(dbgs()))
LOOP_PASS("print<ivusers>", IVUsersPrinterPass(dbgs()))
LOOP_PASS("loop-predication", LoopPredicationPass())
#undef LOOP_PASS

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@ -29,6 +29,7 @@ add_llvm_library(LLVMScalarOpts
LoopInterchange.cpp
LoopLoadElimination.cpp
LoopPassManager.cpp
LoopPredication.cpp
LoopRerollPass.cpp
LoopRotation.cpp
LoopSimplifyCFG.cpp

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@ -0,0 +1,280 @@
//===-- LoopPredication.cpp - Guard based loop predication pass -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The LoopPredication pass tries to convert loop variant range checks to loop
// invariant by widening checks across loop iterations. For example, it will
// convert
//
// for (i = 0; i < n; i++) {
// guard(i < len);
// ...
// }
//
// to
//
// for (i = 0; i < n; i++) {
// guard(n - 1 < len);
// ...
// }
//
// After this transformation the condition of the guard is loop invariant, so
// loop-unswitch can later unswitch the loop by this condition which basically
// predicates the loop by the widened condition:
//
// if (n - 1 < len)
// for (i = 0; i < n; i++) {
// ...
// }
// else
// deoptimize
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Scalar/LoopPredication.h"
#include "llvm/Pass.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/Support/Debug.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
#define DEBUG_TYPE "loop-predication"
using namespace llvm;
namespace {
class LoopPredication {
ScalarEvolution *SE;
Loop *L;
const DataLayout *DL;
BasicBlock *Preheader;
Optional<Value *> widenICmpRangeCheck(ICmpInst *ICI, SCEVExpander &Expander,
IRBuilder<> &Builder);
bool widenGuardConditions(IntrinsicInst *II, SCEVExpander &Expander);
public:
LoopPredication(ScalarEvolution *SE) : SE(SE){};
bool runOnLoop(Loop *L);
};
class LoopPredicationLegacyPass : public LoopPass {
public:
static char ID;
LoopPredicationLegacyPass() : LoopPass(ID) {
initializeLoopPredicationLegacyPassPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
getLoopAnalysisUsage(AU);
}
bool runOnLoop(Loop *L, LPPassManager &LPM) override {
if (skipLoop(L))
return false;
auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
LoopPredication LP(SE);
return LP.runOnLoop(L);
}
};
char LoopPredicationLegacyPass::ID = 0;
} // end namespace llvm
INITIALIZE_PASS_BEGIN(LoopPredicationLegacyPass, "loop-predication",
"Loop predication", false, false)
INITIALIZE_PASS_DEPENDENCY(LoopPass)
INITIALIZE_PASS_END(LoopPredicationLegacyPass, "loop-predication",
"Loop predication", false, false)
Pass *llvm::createLoopPredicationPass() {
return new LoopPredicationLegacyPass();
}
PreservedAnalyses LoopPredicationPass::run(Loop &L, LoopAnalysisManager &AM,
LoopStandardAnalysisResults &AR,
LPMUpdater &U) {
LoopPredication LP(&AR.SE);
if (!LP.runOnLoop(&L))
return PreservedAnalyses::all();
return getLoopPassPreservedAnalyses();
}
/// If ICI can be widened to a loop invariant condition emits the loop
/// invariant condition in the loop preheader and return it, otherwise
/// returns None.
Optional<Value *> LoopPredication::widenICmpRangeCheck(ICmpInst *ICI,
SCEVExpander &Expander,
IRBuilder<> &Builder) {
DEBUG(dbgs() << "Analyzing ICmpInst condition:\n");
DEBUG(ICI->dump());
ICmpInst::Predicate Pred = ICI->getPredicate();
Value *LHS = ICI->getOperand(0);
Value *RHS = ICI->getOperand(1);
const SCEV *LHSS = SE->getSCEV(LHS);
if (isa<SCEVCouldNotCompute>(LHSS))
return None;
const SCEV *RHSS = SE->getSCEV(RHS);
if (isa<SCEVCouldNotCompute>(RHSS))
return None;
// Canonicalize RHS to be loop invariant bound, LHS - a loop computable index
if (SE->isLoopInvariant(LHSS, L)) {
std::swap(LHS, RHS);
std::swap(LHSS, RHSS);
Pred = ICmpInst::getSwappedPredicate(Pred);
}
if (!SE->isLoopInvariant(RHSS, L))
return None;
Value *Bound = RHS;
const SCEVAddRecExpr *IndexAR = dyn_cast<SCEVAddRecExpr>(LHSS);
if (!IndexAR || IndexAR->getLoop() != L)
return None;
DEBUG(dbgs() << "IndexAR: ");
DEBUG(IndexAR->dump());
bool IsIncreasing = false;
if (!SE->isMonotonicPredicate(IndexAR, Pred, IsIncreasing))
return None;
// If the predicate is increasing the condition can change from false to true
// as the loop progresses, in this case take the value on the first iteration
// for the widened check. Otherwise the condition can change from true to
// false as the loop progresses, so take the value on the last iteration.
const SCEV *NewLHSS = IsIncreasing
? IndexAR->getStart()
: SE->getSCEVAtScope(IndexAR, L->getParentLoop());
if (NewLHSS == IndexAR) {
DEBUG(dbgs() << "Can't compute NewLHSS!");
return None;
}
DEBUG(dbgs() << "NewLHSS: ");
DEBUG(NewLHSS->dump());
if (!SE->isLoopInvariant(NewLHSS, L) || !isSafeToExpand(NewLHSS, *SE))
return None;
DEBUG(dbgs() << "NewLHSS is loop invariant and safe to expand. Expand!\n");
Value *NewLHS = Expander.expandCodeFor(NewLHSS, Bound->getType(),
Preheader->getTerminator());
return Builder.CreateICmp(Pred, NewLHS, Bound);
}
bool LoopPredication::widenGuardConditions(IntrinsicInst *Guard,
SCEVExpander &Expander) {
DEBUG(dbgs() << "Processing guard:\n");
DEBUG(Guard->dump());
IRBuilder<> Builder(cast<Instruction>(Preheader->getTerminator()));
// The guard condition is expected to be in form of:
// cond1 && cond2 && cond3 ...
// Iterate over subconditions looking for for icmp conditions which can be
// widened across loop iterations. Widening these conditions remember the
// resulting list of subconditions in Checks vector.
SmallVector<Value *, 4> Worklist(1, Guard->getOperand(0));
SmallPtrSet<Value *, 4> Visited;
SmallVector<Value *, 4> Checks;
unsigned NumWidened = 0;
do {
Value *Condition = Worklist.pop_back_val();
if (!Visited.insert(Condition).second)
continue;
Value *LHS, *RHS;
using namespace llvm::PatternMatch;
if (match(Condition, m_And(m_Value(LHS), m_Value(RHS)))) {
Worklist.push_back(LHS);
Worklist.push_back(RHS);
continue;
}
if (ICmpInst *ICI = dyn_cast<ICmpInst>(Condition)) {
if (auto NewRangeCheck = widenICmpRangeCheck(ICI, Expander, Builder)) {
Checks.push_back(NewRangeCheck.getValue());
NumWidened++;
continue;
}
}
// Save the condition as is if we can't widen it
Checks.push_back(Condition);
} while (Worklist.size() != 0);
if (NumWidened == 0)
return false;
// Emit the new guard condition
Builder.SetInsertPoint(Guard);
Value *LastCheck = nullptr;
for (auto *Check : Checks)
if (!LastCheck)
LastCheck = Check;
else
LastCheck = Builder.CreateAnd(LastCheck, Check);
Guard->setOperand(0, LastCheck);
DEBUG(dbgs() << "Widened checks = " << NumWidened << "\n");
return true;
}
bool LoopPredication::runOnLoop(Loop *Loop) {
L = Loop;
DEBUG(dbgs() << "Analyzing ");
DEBUG(L->dump());
Module *M = L->getHeader()->getModule();
// There is nothing to do if the module doesn't use guards
auto *GuardDecl =
M->getFunction(Intrinsic::getName(Intrinsic::experimental_guard));
if (!GuardDecl || GuardDecl->use_empty())
return false;
DL = &M->getDataLayout();
Preheader = L->getLoopPreheader();
if (!Preheader)
return false;
// Collect all the guards into a vector and process later, so as not
// to invalidate the instruction iterator.
SmallVector<IntrinsicInst *, 4> Guards;
for (const auto BB : L->blocks())
for (auto &I : *BB)
if (auto *II = dyn_cast<IntrinsicInst>(&I))
if (II->getIntrinsicID() == Intrinsic::experimental_guard)
Guards.push_back(II);
SCEVExpander Expander(*SE, *DL, "loop-predication");
bool Changed = false;
for (auto *Guard : Guards)
Changed |= widenGuardConditions(Guard, Expander);
return Changed;
}

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@ -58,6 +58,7 @@ void llvm::initializeScalarOpts(PassRegistry &Registry) {
initializeLoopAccessLegacyAnalysisPass(Registry);
initializeLoopInstSimplifyLegacyPassPass(Registry);
initializeLoopInterchangePass(Registry);
initializeLoopPredicationLegacyPassPass(Registry);
initializeLoopRotateLegacyPassPass(Registry);
initializeLoopStrengthReducePass(Registry);
initializeLoopRerollPass(Registry);

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@ -0,0 +1,496 @@
; RUN: opt -S -loop-predication < %s 2>&1 | FileCheck %s
; RUN: opt -S -passes='require<scalar-evolution>,loop(loop-predication)' < %s 2>&1 | FileCheck %s
declare void @llvm.experimental.guard(i1, ...)
define i32 @unsigned_loop_0_to_n_ult_check(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @unsigned_loop_0_to_n_ult_check
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp ult i32 [[max_index]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds = icmp ult i32 %i, %length
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @unsigned_loop_0_to_n_ugt_check(i32* %array, i32 %length, i32 %n) {
; CHECK-LABEL: @unsigned_loop_0_to_n_ugt_check
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp ult i32 [[max_index]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds = icmp ugt i32 %length, %i
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @two_range_checks(i32* %array.1, i32 %length.1,
i32* %array.2, i32 %length.2, i32 %n) {
; CHECK-LABEL: @two_range_checks
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond_1:[^ ]+]] = icmp ult i32 [[max_index]], %length.{{1|2}}
; CHECK-NEXT: [[wide_cond_2:[^ ]+]] = icmp ult i32 [[max_index]], %length.{{1|2}}
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: [[wide_cond:[^ ]+]] = and i1 [[wide_cond_1]], [[wide_cond_2]]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds.1 = icmp ult i32 %i, %length.1
%within.bounds.2 = icmp ult i32 %i, %length.2
%within.bounds = and i1 %within.bounds.1, %within.bounds.2
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
%array.1.i = load i32, i32* %array.1.i.ptr, align 4
%loop.acc.1 = add i32 %loop.acc, %array.1.i
%array.2.i.ptr = getelementptr inbounds i32, i32* %array.2, i64 %i.i64
%array.2.i = load i32, i32* %array.2.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc.1, %array.2.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @three_range_checks(i32* %array.1, i32 %length.1,
i32* %array.2, i32 %length.2,
i32* %array.3, i32 %length.3, i32 %n) {
; CHECK-LABEL: @three_range_checks
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond_1:[^ ]+]] = icmp ult i32 [[max_index]], %length.{{1|2|3}}
; CHECK-NEXT: [[wide_cond_2:[^ ]+]] = icmp ult i32 [[max_index]], %length.{{1|2|3}}
; CHECK-NEXT: [[wide_cond_3:[^ ]+]] = icmp ult i32 [[max_index]], %length.{{1|2|3}}
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: [[wide_cond_and:[^ ]+]] = and i1 [[wide_cond_1]], [[wide_cond_2]]
; CHECK-NEXT: [[wide_cond:[^ ]+]] = and i1 [[wide_cond_and]], [[wide_cond_3]]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds.1 = icmp ult i32 %i, %length.1
%within.bounds.2 = icmp ult i32 %i, %length.2
%within.bounds.3 = icmp ult i32 %i, %length.3
%within.bounds.1.and.2 = and i1 %within.bounds.1, %within.bounds.2
%within.bounds = and i1 %within.bounds.1.and.2, %within.bounds.3
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
%array.1.i = load i32, i32* %array.1.i.ptr, align 4
%loop.acc.1 = add i32 %loop.acc, %array.1.i
%array.2.i.ptr = getelementptr inbounds i32, i32* %array.2, i64 %i.i64
%array.2.i = load i32, i32* %array.2.i.ptr, align 4
%loop.acc.2 = add i32 %loop.acc.1, %array.2.i
%array.3.i.ptr = getelementptr inbounds i32, i32* %array.3, i64 %i.i64
%array.3.i = load i32, i32* %array.3.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc.2, %array.3.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @three_guards(i32* %array.1, i32 %length.1,
i32* %array.2, i32 %length.2,
i32* %array.3, i32 %length.3, i32 %n) {
; CHECK-LABEL: @three_guards
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond_1:[^ ]+]] = icmp ult i32 [[max_index]], %length.1
; CHECK-NEXT: [[wide_cond_2:[^ ]+]] = icmp ult i32 [[max_index]], %length.2
; CHECK-NEXT: [[wide_cond_3:[^ ]+]] = icmp ult i32 [[max_index]], %length.3
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond_1]], i32 9) [ "deopt"() ]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond_2]], i32 9) [ "deopt"() ]
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond_3]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds.1 = icmp ult i32 %i, %length.1
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds.1, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.1.i.ptr = getelementptr inbounds i32, i32* %array.1, i64 %i.i64
%array.1.i = load i32, i32* %array.1.i.ptr, align 4
%loop.acc.1 = add i32 %loop.acc, %array.1.i
%within.bounds.2 = icmp ult i32 %i, %length.2
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds.2, i32 9) [ "deopt"() ]
%array.2.i.ptr = getelementptr inbounds i32, i32* %array.2, i64 %i.i64
%array.2.i = load i32, i32* %array.2.i.ptr, align 4
%loop.acc.2 = add i32 %loop.acc.1, %array.2.i
%within.bounds.3 = icmp ult i32 %i, %length.3
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds.3, i32 9) [ "deopt"() ]
%array.3.i.ptr = getelementptr inbounds i32, i32* %array.3, i64 %i.i64
%array.3.i = load i32, i32* %array.3.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc.2, %array.3.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @signed_loop_start_to_n_sge_0_check(i32* %array, i32 %length, i32 %start, i32 %n) {
; CHECK-LABEL: @signed_loop_start_to_n_sge_0_check
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp sge i32 %start, 0
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ %start, %loop.preheader ]
%within.bounds = icmp sge i32 %i, 0
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nsw i32 %i, 1
%continue = icmp slt i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @signed_loop_start_to_n_upper_slt_length_check(i32* %array, i32 %length, i32 %start, i32 %n) {
; CHECK-LABEL: @signed_loop_start_to_n_upper_slt_length_check
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[start_1:[^ ]+]] = add i32 %start, 1
; CHECK-NEXT: [[n_sgt_start_1:[^ ]+]] = icmp sgt i32 %n, [[start_1]]
; CHECK-NEXT: [[smax:[^ ]+]] = select i1 [[n_sgt_start_1]], i32 %n, i32 [[start_1]]
; CHECK-NEXT: [[max_index:[^ ]+]] = add i32 [[smax]], -1
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp slt i32 [[max_index]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ %start, %loop.preheader ]
%within.bounds = icmp slt i32 %i, %length
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nsw i32 %i, 1
%continue = icmp slt i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @signed_loop_start_to_n_both_checks(i32* %array, i32 %length, i32 %start, i32 %n) {
; CHECK-LABEL: @signed_loop_start_to_n_both_checks
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[lower_check:[^ ]+]] = icmp sge i32 %start, 0
; CHECK-NEXT: [[start_1:[^ ]+]] = add i32 %start, 1
; CHECK-NEXT: [[n_sgt_start_1:[^ ]+]] = icmp sgt i32 %n, [[start_1]]
; CHECK-NEXT: [[smax:[^ ]+]] = select i1 [[n_sgt_start_1]], i32 %n, i32 [[start_1]]
; CHECK-NEXT: [[max_index:[^ ]+]] = add i32 [[smax]], -1
; CHECK-NEXT: [[upper_check:[^ ]+]] = icmp slt i32 [[max_index]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: [[wide_cond:[^ ]+]] = and i1 [[lower_check]], [[upper_check]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ %start, %loop.preheader ]
%within.bounds.1 = icmp slt i32 %i, %length
%within.bounds.2 = icmp sge i32 %i, 0
%within.bounds = and i1 %within.bounds.1, %within.bounds.2
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nsw i32 %i, 1
%continue = icmp slt i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @unsigned_loop_0_to_n_unrelated_condition(i32* %array, i32 %length, i32 %n, i32 %x) {
; CHECK-LABEL: @unsigned_loop_0_to_n_unrelated_condition
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[max_index:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp ult i32 [[max_index]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: %unrelated.cond = icmp ult i32 %x, %length
; CHECK: [[guard_cond:[^ ]+]] = and i1 %unrelated.cond, [[wide_cond]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[guard_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds = icmp ult i32 %i, %length
%unrelated.cond = icmp ult i32 %x, %length
%guard.cond = and i1 %within.bounds, %unrelated.cond
call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
; Don't change the guard condition if there were no widened subconditions
define i32 @test_no_widened_conditions(i32* %array, i32 %length, i32 %n, i32 %x1, i32 %x2, i32 %x3) {
; CHECK-LABEL: @test_no_widened_conditions
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: %unrelated.cond.1 = icmp eq i32 %x1, %i
; CHECK-NEXT: %unrelated.cond.2 = icmp eq i32 %x2, %i
; CHECK-NEXT: %unrelated.cond.3 = icmp eq i32 %x3, %i
; CHECK-NEXT: %unrelated.cond.and.1 = and i1 %unrelated.cond.1, %unrelated.cond.2
; CHECK-NEXT: %guard.cond = and i1 %unrelated.cond.and.1, %unrelated.cond.3
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond, i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%unrelated.cond.1 = icmp eq i32 %x1, %i
%unrelated.cond.2 = icmp eq i32 %x2, %i
%unrelated.cond.3 = icmp eq i32 %x3, %i
%unrelated.cond.and.1 = and i1 %unrelated.cond.1, %unrelated.cond.2
%guard.cond = and i1 %unrelated.cond.and.1, %unrelated.cond.3
call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @signed_loop_start_to_n_loop_variant_bound(i32* %array, i32 %x, i32 %start, i32 %n) {
; CHECK-LABEL: @signed_loop_start_to_n_loop_variant_bound
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: %bound = add i32 %i, %x
; CHECK-NEXT: %within.bounds = icmp slt i32 %i, %bound
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ %start, %loop.preheader ]
%bound = add i32 %i, %x
%within.bounds = icmp slt i32 %i, %bound
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nsw i32 %i, 1
%continue = icmp slt i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}
define i32 @signed_loop_start_to_n_non_monotonic_predicate(i32* %array, i32 %x, i32 %start, i32 %n) {
; CHECK-LABEL: @signed_loop_start_to_n_non_monotonic_predicate
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: %guard.cond = icmp eq i32 %i, %x
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond, i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ %start, %loop.preheader ]
%guard.cond = icmp eq i32 %i, %x
call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nsw i32 %i, 1
%continue = icmp slt i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}

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; RUN: opt -S -loop-predication < %s 2>&1 | FileCheck %s
; RUN: opt -S -passes='require<scalar-evolution>,loop(loop-predication)' < %s 2>&1 | FileCheck %s
declare void @llvm.experimental.guard(i1, ...)
define i32 @signed_loop_0_to_n_nested_0_to_l_inner_index_check(i32* %array, i32 %length, i32 %n, i32 %l) {
; CHECK-LABEL: @signed_loop_0_to_n_nested_0_to_l_inner_index_check
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %outer.loop.preheader
outer.loop.preheader:
; CHECK: outer.loop.preheader:
; CHECK: [[iteration_count:[^ ]+]] = add i32 %l, -1
br label %outer.loop
outer.loop:
%outer.loop.acc = phi i32 [ %outer.loop.acc.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%i = phi i32 [ %i.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%tmp6 = icmp sle i32 %l, 0
br i1 %tmp6, label %outer.loop.inc, label %inner.loop.preheader
inner.loop.preheader:
; CHECK: inner.loop.preheader:
; CHECK: [[wide_cond:[^ ]+]] = icmp slt i32 [[iteration_count]], %length
br label %inner.loop
inner.loop:
; CHECK: inner.loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%inner.loop.acc = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %inner.loop.preheader ]
%j = phi i32 [ %j.next, %inner.loop ], [ 0, %inner.loop.preheader ]
%within.bounds = icmp slt i32 %j, %length
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%j.i64 = zext i32 %j to i64
%array.j.ptr = getelementptr inbounds i32, i32* %array, i64 %j.i64
%array.j = load i32, i32* %array.j.ptr, align 4
%inner.loop.acc.next = add i32 %inner.loop.acc, %array.j
%j.next = add nsw i32 %j, 1
%inner.continue = icmp slt i32 %j.next, %l
br i1 %inner.continue, label %inner.loop, label %outer.loop.inc
outer.loop.inc:
%outer.loop.acc.next = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %outer.loop ]
%i.next = add nsw i32 %i, 1
%outer.continue = icmp slt i32 %i.next, %n
br i1 %outer.continue, label %outer.loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %outer.loop.acc.next, %outer.loop.inc ]
ret i32 %result
}
define i32 @signed_loop_0_to_n_nested_0_to_l_outer_index_check(i32* %array, i32 %length, i32 %n, i32 %l) {
; CHECK-LABEL: @signed_loop_0_to_n_nested_0_to_l_outer_index_check
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %outer.loop.preheader
outer.loop.preheader:
; CHECK: outer.loop.preheader:
; CHECK: [[iteration_count:[^ ]+]] = add i32 %n, -1
; CHECK: [[wide_cond:[^ ]+]] = icmp slt i32 [[iteration_count]], %length
br label %outer.loop
outer.loop:
%outer.loop.acc = phi i32 [ %outer.loop.acc.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%i = phi i32 [ %i.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%tmp6 = icmp sle i32 %l, 0
br i1 %tmp6, label %outer.loop.inc, label %inner.loop.preheader
inner.loop.preheader:
br label %inner.loop
inner.loop:
; CHECK: inner.loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%inner.loop.acc = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %inner.loop.preheader ]
%j = phi i32 [ %j.next, %inner.loop ], [ 0, %inner.loop.preheader ]
%within.bounds = icmp slt i32 %i, %length
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%inner.loop.acc.next = add i32 %inner.loop.acc, %array.i
%j.next = add nsw i32 %j, 1
%inner.continue = icmp slt i32 %j.next, %l
br i1 %inner.continue, label %inner.loop, label %outer.loop.inc
outer.loop.inc:
%outer.loop.acc.next = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %outer.loop ]
%i.next = add nsw i32 %i, 1
%outer.continue = icmp slt i32 %i.next, %n
br i1 %outer.continue, label %outer.loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %outer.loop.acc.next, %outer.loop.inc ]
ret i32 %result
}
define i32 @signed_loop_0_to_n_nested_i_to_l_inner_index_check(i32* %array, i32 %length, i32 %n, i32 %l) {
; CHECK-LABEL: @signed_loop_0_to_n_nested_i_to_l_inner_index_check
entry:
%tmp5 = icmp sle i32 %n, 0
br i1 %tmp5, label %exit, label %outer.loop.preheader
outer.loop.preheader:
br label %outer.loop
outer.loop:
; CHECK: outer.loop:
; CHECK: [[i_1:[^ ]+]] = add i32 %i, 1
; CHECK-NEXT: [[l_sgt_i_1:[^ ]+]] = icmp sgt i32 %l, [[i_1]]
; CHECK-NEXT: [[smax:[^ ]+]] = select i1 [[l_sgt_i_1]], i32 %l, i32 [[i_1]]
; CHECK-NEXT: [[max_j:[^ ]+]] = add i32 [[smax]], -1
%outer.loop.acc = phi i32 [ %outer.loop.acc.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%i = phi i32 [ %i.next, %outer.loop.inc ], [ 0, %outer.loop.preheader ]
%tmp6 = icmp sle i32 %l, 0
br i1 %tmp6, label %outer.loop.inc, label %inner.loop.preheader
inner.loop.preheader:
; CHECK: inner.loop.preheader:
; CHECK: [[wide_cond:[^ ]+]] = icmp slt i32 [[max_j]], %length
br label %inner.loop
inner.loop:
; CHECK: inner.loop:
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 [[wide_cond]], i32 9) [ "deopt"() ]
%inner.loop.acc = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %inner.loop.preheader ]
%j = phi i32 [ %j.next, %inner.loop ], [ %i, %inner.loop.preheader ]
%within.bounds = icmp slt i32 %j, %length
call void (i1, ...) @llvm.experimental.guard(i1 %within.bounds, i32 9) [ "deopt"() ]
%j.i64 = zext i32 %j to i64
%array.j.ptr = getelementptr inbounds i32, i32* %array, i64 %j.i64
%array.j = load i32, i32* %array.j.ptr, align 4
%inner.loop.acc.next = add i32 %inner.loop.acc, %array.j
%j.next = add nsw i32 %j, 1
%inner.continue = icmp slt i32 %j.next, %l
br i1 %inner.continue, label %inner.loop, label %outer.loop.inc
outer.loop.inc:
%outer.loop.acc.next = phi i32 [ %inner.loop.acc.next, %inner.loop ], [ %outer.loop.acc, %outer.loop ]
%i.next = add nsw i32 %i, 1
%outer.continue = icmp slt i32 %i.next, %n
br i1 %outer.continue, label %outer.loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %outer.loop.acc.next, %outer.loop.inc ]
ret i32 %result
}

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; RUN: opt -S -loop-predication < %s 2>&1 | FileCheck %s
; RUN: opt -S -passes='require<scalar-evolution>,loop(loop-predication)' < %s 2>&1 | FileCheck %s
declare void @llvm.experimental.guard(i1, ...)
define i32 @test_visited(i32* %array, i32 %length, i32 %n, i32 %x) {
; CHECK-LABEL: @test_visited
entry:
%tmp5 = icmp eq i32 %n, 0
br i1 %tmp5, label %exit, label %loop.preheader
loop.preheader:
; CHECK: loop.preheader:
; CHECK: [[iteration_count:[^ ]+]] = add i32 %n, -1
; CHECK-NEXT: [[wide_cond:[^ ]+]] = icmp ult i32 [[iteration_count]], %length
; CHECK-NEXT: br label %loop
br label %loop
loop:
; CHECK: loop:
; CHECK: %unrelated.cond = icmp eq i32 %x, %i
; CHECK: [[guard_cond:[^ ]+]] = and i1 %unrelated.cond, [[wide_cond]]
; CHECK-NEXT: call void (i1, ...) @llvm.experimental.guard(i1 [[guard_cond]], i32 9) [ "deopt"() ]
%loop.acc = phi i32 [ %loop.acc.next, %loop ], [ 0, %loop.preheader ]
%i = phi i32 [ %i.next, %loop ], [ 0, %loop.preheader ]
%within.bounds = icmp ult i32 %i, %length
%unrelated.cond = icmp eq i32 %x, %i
%guard.cond.2 = and i1 %within.bounds, %unrelated.cond
%guard.cond.3 = and i1 %guard.cond.2, %unrelated.cond
%guard.cond.4 = and i1 %guard.cond.3, %guard.cond.2
%guard.cond.5 = and i1 %guard.cond.4, %guard.cond.3
%guard.cond.6 = and i1 %guard.cond.5, %guard.cond.4
%guard.cond.7 = and i1 %guard.cond.6, %guard.cond.5
%guard.cond.8 = and i1 %guard.cond.7, %guard.cond.6
%guard.cond.9 = and i1 %guard.cond.8, %guard.cond.7
%guard.cond.10 = and i1 %guard.cond.9, %guard.cond.8
%guard.cond.11 = and i1 %guard.cond.10, %guard.cond.9
%guard.cond.12 = and i1 %guard.cond.11, %guard.cond.10
%guard.cond.13 = and i1 %guard.cond.12, %guard.cond.11
%guard.cond.14 = and i1 %guard.cond.13, %guard.cond.12
%guard.cond.15 = and i1 %guard.cond.14, %guard.cond.13
%guard.cond.16 = and i1 %guard.cond.15, %guard.cond.14
%guard.cond.17 = and i1 %guard.cond.16, %guard.cond.15
%guard.cond.18 = and i1 %guard.cond.17, %guard.cond.16
%guard.cond.19 = and i1 %guard.cond.18, %guard.cond.17
%guard.cond.20 = and i1 %guard.cond.19, %guard.cond.18
%guard.cond.21 = and i1 %guard.cond.20, %guard.cond.19
%guard.cond.22 = and i1 %guard.cond.21, %guard.cond.20
%guard.cond.23 = and i1 %guard.cond.22, %guard.cond.21
%guard.cond.24 = and i1 %guard.cond.23, %guard.cond.22
%guard.cond.25 = and i1 %guard.cond.24, %guard.cond.23
%guard.cond.26 = and i1 %guard.cond.25, %guard.cond.24
%guard.cond.27 = and i1 %guard.cond.26, %guard.cond.25
%guard.cond.28 = and i1 %guard.cond.27, %guard.cond.26
%guard.cond.29 = and i1 %guard.cond.28, %guard.cond.27
%guard.cond.30 = and i1 %guard.cond.29, %guard.cond.28
%guard.cond.31 = and i1 %guard.cond.30, %guard.cond.29
%guard.cond.32 = and i1 %guard.cond.31, %guard.cond.30
%guard.cond.33 = and i1 %guard.cond.32, %guard.cond.31
%guard.cond.34 = and i1 %guard.cond.33, %guard.cond.32
%guard.cond.35 = and i1 %guard.cond.34, %guard.cond.33
%guard.cond.36 = and i1 %guard.cond.35, %guard.cond.34
%guard.cond.37 = and i1 %guard.cond.36, %guard.cond.35
%guard.cond.38 = and i1 %guard.cond.37, %guard.cond.36
%guard.cond.39 = and i1 %guard.cond.38, %guard.cond.37
%guard.cond.40 = and i1 %guard.cond.39, %guard.cond.38
%guard.cond.41 = and i1 %guard.cond.40, %guard.cond.39
%guard.cond.42 = and i1 %guard.cond.41, %guard.cond.40
%guard.cond.43 = and i1 %guard.cond.42, %guard.cond.41
%guard.cond.44 = and i1 %guard.cond.43, %guard.cond.42
%guard.cond.45 = and i1 %guard.cond.44, %guard.cond.43
%guard.cond.46 = and i1 %guard.cond.45, %guard.cond.44
%guard.cond.47 = and i1 %guard.cond.46, %guard.cond.45
%guard.cond.48 = and i1 %guard.cond.47, %guard.cond.46
%guard.cond.49 = and i1 %guard.cond.48, %guard.cond.47
%guard.cond.50 = and i1 %guard.cond.49, %guard.cond.48
%guard.cond.51 = and i1 %guard.cond.50, %guard.cond.49
%guard.cond.52 = and i1 %guard.cond.51, %guard.cond.50
%guard.cond.53 = and i1 %guard.cond.52, %guard.cond.51
%guard.cond.54 = and i1 %guard.cond.53, %guard.cond.52
%guard.cond.55 = and i1 %guard.cond.54, %guard.cond.53
%guard.cond.56 = and i1 %guard.cond.55, %guard.cond.54
%guard.cond.57 = and i1 %guard.cond.56, %guard.cond.55
%guard.cond.58 = and i1 %guard.cond.57, %guard.cond.56
%guard.cond.59 = and i1 %guard.cond.58, %guard.cond.57
%guard.cond.60 = and i1 %guard.cond.59, %guard.cond.58
%guard.cond.61 = and i1 %guard.cond.60, %guard.cond.59
%guard.cond.62 = and i1 %guard.cond.61, %guard.cond.60
%guard.cond.63 = and i1 %guard.cond.62, %guard.cond.61
%guard.cond.64 = and i1 %guard.cond.63, %guard.cond.62
%guard.cond.65 = and i1 %guard.cond.64, %guard.cond.63
%guard.cond.66 = and i1 %guard.cond.65, %guard.cond.64
%guard.cond.67 = and i1 %guard.cond.66, %guard.cond.65
%guard.cond.68 = and i1 %guard.cond.67, %guard.cond.66
%guard.cond.69 = and i1 %guard.cond.68, %guard.cond.67
%guard.cond.70 = and i1 %guard.cond.69, %guard.cond.68
%guard.cond.71 = and i1 %guard.cond.70, %guard.cond.69
%guard.cond.72 = and i1 %guard.cond.71, %guard.cond.70
%guard.cond.73 = and i1 %guard.cond.72, %guard.cond.71
%guard.cond.74 = and i1 %guard.cond.73, %guard.cond.72
%guard.cond.75 = and i1 %guard.cond.74, %guard.cond.73
%guard.cond.76 = and i1 %guard.cond.75, %guard.cond.74
%guard.cond.77 = and i1 %guard.cond.76, %guard.cond.75
%guard.cond.78 = and i1 %guard.cond.77, %guard.cond.76
%guard.cond.79 = and i1 %guard.cond.78, %guard.cond.77
%guard.cond.80 = and i1 %guard.cond.79, %guard.cond.78
%guard.cond.81 = and i1 %guard.cond.80, %guard.cond.79
%guard.cond.82 = and i1 %guard.cond.81, %guard.cond.80
%guard.cond.83 = and i1 %guard.cond.82, %guard.cond.81
%guard.cond.84 = and i1 %guard.cond.83, %guard.cond.82
%guard.cond.85 = and i1 %guard.cond.84, %guard.cond.83
%guard.cond.86 = and i1 %guard.cond.85, %guard.cond.84
%guard.cond.87 = and i1 %guard.cond.86, %guard.cond.85
%guard.cond.88 = and i1 %guard.cond.87, %guard.cond.86
%guard.cond.89 = and i1 %guard.cond.88, %guard.cond.87
%guard.cond.90 = and i1 %guard.cond.89, %guard.cond.88
%guard.cond.91 = and i1 %guard.cond.90, %guard.cond.89
%guard.cond.92 = and i1 %guard.cond.91, %guard.cond.90
%guard.cond.93 = and i1 %guard.cond.92, %guard.cond.91
%guard.cond.94 = and i1 %guard.cond.93, %guard.cond.92
%guard.cond.95 = and i1 %guard.cond.94, %guard.cond.93
%guard.cond.96 = and i1 %guard.cond.95, %guard.cond.94
%guard.cond.97 = and i1 %guard.cond.96, %guard.cond.95
%guard.cond.98 = and i1 %guard.cond.97, %guard.cond.96
%guard.cond.99 = and i1 %guard.cond.98, %guard.cond.97
call void (i1, ...) @llvm.experimental.guard(i1 %guard.cond.99, i32 9) [ "deopt"() ]
%i.i64 = zext i32 %i to i64
%array.i.ptr = getelementptr inbounds i32, i32* %array, i64 %i.i64
%array.i = load i32, i32* %array.i.ptr, align 4
%loop.acc.next = add i32 %loop.acc, %array.i
%i.next = add nuw i32 %i, 1
%continue = icmp ult i32 %i.next, %n
br i1 %continue, label %loop, label %exit
exit:
%result = phi i32 [ 0, %entry ], [ %loop.acc.next, %loop ]
ret i32 %result
}