[llvm] r218721 - [InstCombine] Optimize icmp-select-icmp
Chandler Carruth
chandlerc at google.com
Wed Oct 1 02:17:44 PDT 2014
Evgeniy, if this is still breaking the bot, let's just revert it. What with
timezones it'll be a while before Gerolf can likely look at it again and I
think its more important to have the bots green in the interim.
On Wed, Oct 1, 2014 at 2:14 AM, Evgeniy Stepanov <eugeni.stepanov at gmail.com>
wrote:
> Does not look like it helped:
> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/13128
>
>
> On Wed, Oct 1, 2014 at 8:16 AM, Chandler Carruth <chandlerc at google.com>
> wrote:
> > Awesome, thanks!
> >
> > On Sep 30, 2014 8:37 PM, "Gerolf Hoflehner" <ghoflehner at apple.com>
> wrote:
> >>
> >> The fix is
> >>
> >> Committed revision 218735.
> >>
> >>
> >> On Sep 30, 2014, at 8:30 PM, Chandler Carruth <chandlerc at google.com>
> >> wrote:
> >>
> >> It's already been 3 hours. Please do one quickly, I'm worried about the
> >> number of commits going in after this that aren't getting sanitizer
> >> coverage.
> >>
> >> On Tue, Sep 30, 2014 at 8:21 PM, Gerolf Hoflehner <ghoflehner at apple.com
> >
> >> wrote:
> >>>
> >>> Ok, thanks! I’ll provide a fix or back out shortly.
> >>>
> >>>
> >>> On Sep 30, 2014, at 6:13 PM, Chandler Carruth <chandlerc at google.com>
> >>> wrote:
> >>>
> >>> FYI, this is assert failing on build bots:
> >>> http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/13123
> >>>
> >>> On Tue, Sep 30, 2014 at 5:13 PM, Gerolf Hoflehner <
> ghoflehner at apple.com>
> >>> wrote:
> >>>>
> >>>> Author: ghoflehner
> >>>> Date: Tue Sep 30 19:13:22 2014
> >>>> New Revision: 218721
> >>>>
> >>>> URL: http://llvm.org/viewvc/llvm-project?rev=218721&view=rev
> >>>> Log:
> >>>> [InstCombine] Optimize icmp-select-icmp
> >>>>
> >>>> In special cases select instructions can be eliminated by
> >>>> replacing them with a cheaper bitwise operation even when the
> >>>> select result is used outside its home block. The instances
> implemented
> >>>> are patterns like
> >>>> %x=icmp.eq
> >>>> %y=select %x,%r, null
> >>>> %z=icmp.eq|neq %y, null
> >>>> br %z,true, false
> >>>> ==> %x=icmp.ne
> >>>> %y=icmp.eq %r,null
> >>>> %z=or %x,%y
> >>>> br %z,true,false
> >>>> The optimization is integrated into the instruction
> >>>> combiner and performed only when all uses of the select result can
> >>>> be replaced by the select operand proper. For this dominator
> information
> >>>> is used and dominance is now a required analysis pass in the combiner.
> >>>> The optimization itself is iterative. The critical step is to replace
> >>>> the
> >>>> select result with the non-constant select operand. So the select
> >>>> becomes
> >>>> local and the combiner iteratively works out simpler code pattern and
> >>>> eventually eliminates the select.
> >>>>
> >>>> rdar://17853760
> >>>>
> >>>>
> >>>> Added:
> >>>> llvm/trunk/test/Transforms/InstCombine/select-cmp-br.ll
> >>>> Modified:
> >>>> llvm/trunk/lib/Transforms/InstCombine/InstCombine.h
> >>>> llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
> >>>> llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
> >>>> llvm/trunk/test/Transforms/InstCombine/pr12338.ll
> >>>>
> >>>> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombine.h
> >>>> URL:
> >>>>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombine.h?rev=218721&r1=218720&r2=218721&view=diff
> >>>>
> >>>>
> ==============================================================================
> >>>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombine.h (original)
> >>>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombine.h Tue Sep 30
> >>>> 19:13:22 2014
> >>>> @@ -14,6 +14,7 @@
> >>>> #include "llvm/Analysis/AssumptionTracker.h"
> >>>> #include "llvm/Analysis/TargetFolder.h"
> >>>> #include "llvm/Analysis/ValueTracking.h"
> >>>> +#include "llvm/IR/Dominators.h"
> >>>> #include "llvm/IR/IRBuilder.h"
> >>>> #include "llvm/IR/InstVisitor.h"
> >>>> #include "llvm/IR/IntrinsicInst.h"
> >>>> @@ -98,7 +99,7 @@ class LLVM_LIBRARY_VISIBILITY InstCombin
> >>>> AssumptionTracker *AT;
> >>>> const DataLayout *DL;
> >>>> TargetLibraryInfo *TLI;
> >>>> - DominatorTree *DT; // not required
> >>>> + DominatorTree *DT;
> >>>> bool MadeIRChange;
> >>>> LibCallSimplifier *Simplifier;
> >>>> bool MinimizeSize;
> >>>> @@ -113,7 +114,8 @@ public:
> >>>> BuilderTy *Builder;
> >>>>
> >>>> static char ID; // Pass identification, replacement for typeid
> >>>> - InstCombiner() : FunctionPass(ID), DL(nullptr), Builder(nullptr) {
> >>>> + InstCombiner()
> >>>> + : FunctionPass(ID), DL(nullptr), DT(nullptr), Builder(nullptr)
> {
> >>>> MinimizeSize = false;
> >>>> initializeInstCombinerPass(*PassRegistry::getPassRegistry());
> >>>> }
> >>>> @@ -242,6 +244,11 @@ public:
> >>>>
> >>>> // visitInstruction - Specify what to return for unhandled
> >>>> instructions...
> >>>> Instruction *visitInstruction(Instruction &I) { return nullptr; }
> >>>> + bool dominatesAllUses(const Instruction *DI, const Instruction *UI,
> >>>> + const BasicBlock *DB) const;
> >>>> + bool replacedSelectWithOperand(SelectInst *SI, const ICmpInst
> *Icmp,
> >>>> + const ConstantInt *CI1,
> >>>> + const ConstantInt *CI2);
> >>>>
> >>>> private:
> >>>> bool ShouldChangeType(Type *From, Type *To) const;
> >>>>
> >>>> Modified:
> llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
> >>>> URL:
> >>>>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=218721&r1=218720&r2=218721&view=diff
> >>>>
> >>>>
> ==============================================================================
> >>>> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
> >>>> (original)
> >>>> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue
> >>>> Sep 30 19:13:22 2014
> >>>> @@ -2429,6 +2429,127 @@ static bool swapMayExposeCSEOpportunitie
> >>>> return GlobalSwapBenefits > 0;
> >>>> }
> >>>>
> >>>> +/// \brief Check that one use is in the same block as the definition
> >>>> and all
> >>>> +/// other uses are in blocks dominated by a given block
> >>>> +///
> >>>> +/// \param DI Definition
> >>>> +/// \param UI Use
> >>>> +/// \param DB Block that must dominate all uses of \p DI outside
> >>>> +/// the parent block. Note there can be a use of \p DI in
> \p
> >>>> DB.
> >>>> +/// \return true when \p UI is the only use of \p DI in the parent
> >>>> block
> >>>> +/// and all other uses of \p DI are in blocks dominated by \p DB.
> >>>> +///
> >>>> +bool InstCombiner::dominatesAllUses(const Instruction *DI,
> >>>> + const Instruction *UI,
> >>>> + const BasicBlock *DB) const {
> >>>> + assert(DI && DI->getParent() == UI->getParent() &&
> >>>> + "definition and use must be in the same block");
> >>>> + // DominatorTree available?
> >>>> + if (!DT)
> >>>> + return false;
> >>>> + for (const User *U : DI->users()) {
> >>>> + auto *Usr = cast<Instruction>(U);
> >>>> + if (Usr != UI && !DT->dominates(DB, Usr->getParent()))
> >>>> + return false;
> >>>> + }
> >>>> + return true;
> >>>> +}
> >>>> +
> >>>> +///
> >>>> +/// true when the instruction sequence within a block is
> select-cmp-br.
> >>>> +///
> >>>> +static bool isChainSelectCmpBranch(const SelectInst *SI) {
> >>>> + const BasicBlock *BB = SI->getParent();
> >>>> + if (!BB)
> >>>> + return false;
> >>>> + auto *BI = dyn_cast_or_null<BranchInst>(BB->getTerminator());
> >>>> + if (!BI || BI->getNumSuccessors() != 2)
> >>>> + return false;
> >>>> + auto *IC = dyn_cast<ICmpInst>(BI->getCondition());
> >>>> + if (!IC || (IC->getOperand(0) != SI && IC->getOperand(1) != SI))
> >>>> + return false;
> >>>> + return true;
> >>>> +}
> >>>> +
> >>>> +///
> >>>> +/// \brief True when a select result is replaced by one of its
> operands
> >>>> +/// in select-icmp sequence. This will eventually result in the
> >>>> elimination
> >>>> +/// of the select.
> >>>> +///
> >>>> +/// \param SI Select instruction
> >>>> +/// \param Icmp Compare instruction
> >>>> +/// \param CI1 'true' when first select operand is equal to RHSC of
> >>>> Icmp
> >>>> +/// \param CI2 'true' when second select operand is equal to RHSC of
> >>>> Icmp
> >>>> +///
> >>>> +/// Notes:
> >>>> +/// - The replacement is global and requires dominator information
> >>>> +/// - The caller is responsible for the actual replacement
> >>>> +///
> >>>> +/// Example:
> >>>> +///
> >>>> +/// entry:
> >>>> +/// %4 = select i1 %3, %C* %0, %C* null
> >>>> +/// %5 = icmp eq %C* %4, null
> >>>> +/// br i1 %5, label %9, label %7
> >>>> +/// ...
> >>>> +/// ; <label>:7 ; preds =
> %entry
> >>>> +/// %8 = getelementptr inbounds %C* %4, i64 0, i32 0
> >>>> +/// ...
> >>>> +///
> >>>> +/// can be transformed to
> >>>> +///
> >>>> +/// %5 = icmp eq %C* %0, null
> >>>> +/// %6 = select i1 %3, i1 %5, i1 true
> >>>> +/// br i1 %6, label %9, label %7
> >>>> +/// ...
> >>>> +/// ; <label>:7 ; preds =
> %entry
> >>>> +/// %8 = getelementptr inbounds %C* %0, i64 0, i32 0 // replace by
> >>>> %0!
> >>>> +///
> >>>> +/// Similar when the first operand of the select is a constant or/and
> >>>> +/// the compare is for not equal rather than equal.
> >>>> +///
> >>>> +/// FIXME: Currently the function considers equal compares only. It
> >>>> should be
> >>>> +/// possbile to extend it to not equal compares also.
> >>>> +///
> >>>> +bool InstCombiner::replacedSelectWithOperand(SelectInst *SI,
> >>>> + const ICmpInst *Icmp,
> >>>> + const ConstantInt *CI1,
> >>>> + const ConstantInt *CI2)
> {
> >>>> + if (isChainSelectCmpBranch(SI) && Icmp->isEquality()) {
> >>>> + // Code sequence is select - icmp.[eq|ne] - br
> >>>> + unsigned ReplaceWithOpd = 0;
> >>>> + if (CI1 && !CI1->isZero())
> >>>> + // The first constant operand of the select and the RHS of
> >>>> + // the compare match, so try to substitute
> >>>> + // the select results with its second operand
> >>>> + // Example:
> >>>> + // %4 = select i1 %3, %C* null, %C* %0
> >>>> + // %5 = icmp eq %C* %4, null
> >>>> + // ==> could replace select with second operand
> >>>> + ReplaceWithOpd = 2;
> >>>> + else if (CI2 && !CI2->isZero())
> >>>> + // Similar when the second operand of the select is a constant
> >>>> + // Example:
> >>>> + // %4 = select i1 %3, %C* %0, %C* null
> >>>> + // %5 = icmp eq %C* %4, null
> >>>> + // ==> could replace select with first operand
> >>>> + ReplaceWithOpd = 1;
> >>>> + if (ReplaceWithOpd) {
> >>>> + // Replace select with operand on else path for EQ compares.
> >>>> + // Replace select with operand on then path for NE compares.
> >>>> + BasicBlock *Succ =
> >>>> + Icmp->getPredicate() == ICmpInst::ICMP_EQ
> >>>> + ? SI->getParent()->getTerminator()->getSuccessor(1)
> >>>> + : SI->getParent()->getTerminator()->getSuccessor(0);
> >>>> + if (InstCombiner::dominatesAllUses(SI, Icmp, Succ)) {
> >>>> + SI->replaceAllUsesWith(SI->getOperand(ReplaceWithOpd));
> >>>> + return true;
> >>>> + }
> >>>> + }
> >>>> + }
> >>>> + return false;
> >>>> +}
> >>>> +
> >>>> Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
> >>>> bool Changed = false;
> >>>> Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
> >>>> @@ -2885,8 +3006,21 @@ Instruction *InstCombiner::visitICmpInst
> >>>> // fold to a constant (in which case the icmp is replaced
> with
> >>>> a select
> >>>> // which will usually simplify) or this is the only user of
> the
> >>>> // select (in which case we are trading a select+icmp for a
> >>>> simpler
> >>>> - // select+icmp).
> >>>> - if ((Op1 && Op2) || (LHSI->hasOneUse() && (Op1 || Op2))) {
> >>>> + // select+icmp) or all uses of the select can be replaced
> based
> >>>> on
> >>>> + // dominance information ("Global cases").
> >>>> + bool Transform = false;
> >>>> + if (Op1 && Op2)
> >>>> + Transform = true;
> >>>> + else if (Op1 || Op2) {
> >>>> + if (LHSI->hasOneUse())
> >>>> + Transform = true;
> >>>> + else
> >>>> + // Global cases
> >>>> + Transform = replacedSelectWithOperand(
> >>>> + cast<SelectInst>(LHSI), &I,
> >>>> dyn_cast_or_null<ConstantInt>(Op1),
> >>>> + dyn_cast_or_null<ConstantInt>(Op2));
> >>>> + }
> >>>> + if (Transform) {
> >>>> if (!Op1)
> >>>> Op1 = Builder->CreateICmp(I.getPredicate(),
> >>>> LHSI->getOperand(1),
> >>>> RHSC, I.getName());
> >>>>
> >>>> Modified:
> llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
> >>>> URL:
> >>>>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp?rev=218721&r1=218720&r2=218721&view=diff
> >>>>
> >>>>
> ==============================================================================
> >>>> --- llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp
> >>>> (original)
> >>>> +++ llvm/trunk/lib/Transforms/InstCombine/InstructionCombining.cpp Tue
> >>>> Sep 30 19:13:22 2014
> >>>> @@ -90,6 +90,7 @@ INITIALIZE_PASS_BEGIN(InstCombiner, "ins
> >>>> "Combine redundant instructions", false, false)
> >>>> INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
> >>>> INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
> >>>> +INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
> >>>> INITIALIZE_PASS_END(InstCombiner, "instcombine",
> >>>> "Combine redundant instructions", false, false)
> >>>>
> >>>> @@ -97,6 +98,8 @@ void InstCombiner::getAnalysisUsage(Anal
> >>>> AU.setPreservesCFG();
> >>>> AU.addRequired<AssumptionTracker>();
> >>>> AU.addRequired<TargetLibraryInfo>();
> >>>> + AU.addRequired<DominatorTreeWrapperPass>();
> >>>> + AU.addPreserved<DominatorTreeWrapperPass>();
> >>>> }
> >>>>
> >>>>
> >>>> @@ -2933,12 +2936,9 @@ bool InstCombiner::runOnFunction(Functio
> >>>> AT = &getAnalysis<AssumptionTracker>();
> >>>> DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
> >>>> DL = DLP ? &DLP->getDataLayout() : nullptr;
> >>>> + DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
> >>>> TLI = &getAnalysis<TargetLibraryInfo>();
> >>>>
> >>>> - DominatorTreeWrapperPass *DTWP =
> >>>> - getAnalysisIfAvailable<DominatorTreeWrapperPass>();
> >>>> - DT = DTWP ? &DTWP->getDomTree() : nullptr;
> >>>> -
> >>>> // Minimizing size?
> >>>> MinimizeSize =
> >>>> F.getAttributes().hasAttribute(AttributeSet::FunctionIndex,
> >>>> Attribute::MinSize);
> >>>>
> >>>> Modified: llvm/trunk/test/Transforms/InstCombine/pr12338.ll
> >>>> URL:
> >>>>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/pr12338.ll?rev=218721&r1=218720&r2=218721&view=diff
> >>>>
> >>>>
> ==============================================================================
> >>>> --- llvm/trunk/test/Transforms/InstCombine/pr12338.ll (original)
> >>>> +++ llvm/trunk/test/Transforms/InstCombine/pr12338.ll Tue Sep 30
> >>>> 19:13:22 2014
> >>>> @@ -2,11 +2,11 @@
> >>>>
> >>>> define void @entry() nounwind {
> >>>> entry:
> >>>> +; CHECK: br label %for.cond
> >>>> br label %for.cond
> >>>>
> >>>> for.cond:
> >>>> %local = phi <1 x i32> [ <i32 0>, %entry ], [ %phi2, %cond.end47 ]
> >>>> -; CHECK: sub <1 x i32> <i32 92>, %local
> >>>> %phi3 = sub <1 x i32> zeroinitializer, %local
> >>>> br label %cond.end
> >>>>
> >>>>
> >>>> Added: llvm/trunk/test/Transforms/InstCombine/select-cmp-br.ll
> >>>> URL:
> >>>>
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/select-cmp-br.ll?rev=218721&view=auto
> >>>>
> >>>>
> ==============================================================================
> >>>> --- llvm/trunk/test/Transforms/InstCombine/select-cmp-br.ll (added)
> >>>> +++ llvm/trunk/test/Transforms/InstCombine/select-cmp-br.ll Tue Sep 30
> >>>> 19:13:22 2014
> >>>> @@ -0,0 +1,127 @@
> >>>> +; Replace a 'select' with 'or' in 'select - cmp [eq|ne] - br'
> sequence
> >>>> +; RUN: opt -instcombine -S < %s | FileCheck %s
> >>>> +
> >>>> +%C = type <{ %struct.S }>
> >>>> +%struct.S = type { i64*, i32, i32 }
> >>>> +
> >>>> +declare void @bar(%struct.S *) #1
> >>>> +
> >>>> +define void @test1(%C*) {
> >>>> +entry:
> >>>> + %1 = getelementptr inbounds %C* %0, i64 0, i32 0, i32 0
> >>>> + %m = load i64** %1, align 8
> >>>> + %2 = getelementptr inbounds %C* %0, i64 1, i32 0, i32 0
> >>>> + %n = load i64** %2, align 8
> >>>> + %3 = getelementptr inbounds i64* %m, i64 9
> >>>> + %4 = bitcast i64* %3 to i64 (%C*)**
> >>>> + %5 = load i64 (%C*)** %4, align 8
> >>>> + %6 = icmp eq i64* %m, %n
> >>>> + %7 = select i1 %6, %C* %0, %C* null
> >>>> + %8 = icmp eq %C* %7, null
> >>>> + br i1 %8, label %12, label %10
> >>>> +
> >>>> +; <label>:9 ; preds = %10, %12
> >>>> + ret void
> >>>> +
> >>>> +; <label>:10 ; preds = %entry
> >>>> + %11 = getelementptr inbounds %C* %7, i64 0, i32 0
> >>>> + tail call void @bar(%struct.S* %11)
> >>>> + br label %9
> >>>> +
> >>>> +; <label>:12 ; preds = %entry
> >>>> + %13 = tail call i64 %5(%C* %0)
> >>>> + br label %9
> >>>> +; CHECK-LABEL: @test1(
> >>>> +; CHECK-NOT: select
> >>>> +; CHECK: or
> >>>> +}
> >>>> +
> >>>> +define void @test2(%C*) {
> >>>> +entry:
> >>>> + %1 = getelementptr inbounds %C* %0, i64 0, i32 0, i32 0
> >>>> + %m = load i64** %1, align 8
> >>>> + %2 = getelementptr inbounds %C* %0, i64 1, i32 0, i32 0
> >>>> + %n = load i64** %2, align 8
> >>>> + %3 = getelementptr inbounds i64* %m, i64 9
> >>>> + %4 = bitcast i64* %3 to i64 (%C*)**
> >>>> + %5 = load i64 (%C*)** %4, align 8
> >>>> + %6 = icmp eq i64* %m, %n
> >>>> + %7 = select i1 %6, %C* null, %C* %0
> >>>> + %8 = icmp eq %C* %7, null
> >>>> + br i1 %8, label %12, label %10
> >>>> +
> >>>> +; <label>:9 ; preds = %10, %12
> >>>> + ret void
> >>>> +
> >>>> +; <label>:10 ; preds = %entry
> >>>> + %11 = getelementptr inbounds %C* %7, i64 0, i32 0
> >>>> + tail call void @bar(%struct.S* %11)
> >>>> + br label %9
> >>>> +
> >>>> +; <label>:12 ; preds = %entry
> >>>> + %13 = tail call i64 %5(%C* %0)
> >>>> + br label %9
> >>>> +; CHECK-LABEL: @test2(
> >>>> +; CHECK-NOT: select
> >>>> +; CHECK: or
> >>>> +}
> >>>> +
> >>>> +define void @test3(%C*) {
> >>>> +entry:
> >>>> + %1 = getelementptr inbounds %C* %0, i64 0, i32 0, i32 0
> >>>> + %m = load i64** %1, align 8
> >>>> + %2 = getelementptr inbounds %C* %0, i64 1, i32 0, i32 0
> >>>> + %n = load i64** %2, align 8
> >>>> + %3 = getelementptr inbounds i64* %m, i64 9
> >>>> + %4 = bitcast i64* %3 to i64 (%C*)**
> >>>> + %5 = load i64 (%C*)** %4, align 8
> >>>> + %6 = icmp eq i64* %m, %n
> >>>> + %7 = select i1 %6, %C* %0, %C* null
> >>>> + %8 = icmp ne %C* %7, null
> >>>> + br i1 %8, label %10, label %12
> >>>> +
> >>>> +; <label>:9 ; preds = %10, %12
> >>>> + ret void
> >>>> +
> >>>> +; <label>:10 ; preds = %entry
> >>>> + %11 = getelementptr inbounds %C* %7, i64 0, i32 0
> >>>> + tail call void @bar(%struct.S* %11)
> >>>> + br label %9
> >>>> +
> >>>> +; <label>:12 ; preds = %entry
> >>>> + %13 = tail call i64 %5(%C* %0)
> >>>> + br label %9
> >>>> +; CHECK-LABEL: @test3(
> >>>> +; CHECK-NOT: select
> >>>> +; CHECK: or
> >>>> +}
> >>>> +
> >>>> +define void @test4(%C*) {
> >>>> +entry:
> >>>> + %1 = getelementptr inbounds %C* %0, i64 0, i32 0, i32 0
> >>>> + %m = load i64** %1, align 8
> >>>> + %2 = getelementptr inbounds %C* %0, i64 1, i32 0, i32 0
> >>>> + %n = load i64** %2, align 8
> >>>> + %3 = getelementptr inbounds i64* %m, i64 9
> >>>> + %4 = bitcast i64* %3 to i64 (%C*)**
> >>>> + %5 = load i64 (%C*)** %4, align 8
> >>>> + %6 = icmp eq i64* %m, %n
> >>>> + %7 = select i1 %6, %C* null, %C* %0
> >>>> + %8 = icmp ne %C* %7, null
> >>>> + br i1 %8, label %10, label %12
> >>>> +
> >>>> +; <label>:9 ; preds = %10, %12
> >>>> + ret void
> >>>> +
> >>>> +; <label>:10 ; preds = %entry
> >>>> + %11 = getelementptr inbounds %C* %7, i64 0, i32 0
> >>>> + tail call void @bar(%struct.S* %11)
> >>>> + br label %9
> >>>> +
> >>>> +; <label>:12 ; preds = %entry
> >>>> + %13 = tail call i64 %5(%C* %0)
> >>>> + br label %9
> >>>> +; CHECK-LABEL: @test4(
> >>>> +; CHECK-NOT: select
> >>>> +; CHECK: or
> >>>> +}
> >>>>
> >>>>
> >>>> _______________________________________________
> >>>> llvm-commits mailing list
> >>>> llvm-commits at cs.uiuc.edu
> >>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >>>
> >>>
> >>>
> >>
> >>
> >
> > _______________________________________________
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