Commit f51dd7e3 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r296642: 

------------------------------------------------------------------------
r296642 | hans | 2017-03-01 09:15:08 -0800 (Wed, 01 Mar 2017) | 5 lines

[GVNHoist] Don't hoist unsafe scalars at -Oz (PR31729)

Based on Aditya Kumar's patch:

Differential Revision: https://reviews.llvm.org/D29092
------------------------------------------------------------------------

llvm-svn: 296761
parent 39cb0a1e

llvm/lib/Transforms/Scalar/GVNHoist.cpp

+9 −22
Original line number Diff line number Diff line
@@ -200,13 +200,11 @@ static void combineKnownMetadata(Instruction *ReplInst, Instruction *I) { 
class GVNHoist {

public:

  GVNHoist(DominatorTree *DT, AliasAnalysis *AA, MemoryDependenceResults *MD,

           MemorySSA *MSSA, bool OptForMinSize)

      : DT(DT), AA(AA), MD(MD), MSSA(MSSA), OptForMinSize(OptForMinSize),

        HoistingGeps(OptForMinSize), HoistedCtr(0) {

      // Hoist as far as possible when optimizing for code-size.

      if (OptForMinSize)

        MaxNumberOfBBSInPath = -1;

  }

           MemorySSA *MSSA)

      : DT(DT), AA(AA), MD(MD), MSSA(MSSA),

        HoistingGeps(false),

        HoistedCtr(0)

  { }



  bool run(Function &F) {

    VN.setDomTree(DT);
@@ -251,7 +249,6 @@ private: 
  AliasAnalysis *AA;

  MemoryDependenceResults *MD;

  MemorySSA *MSSA;

  const bool OptForMinSize;

  const bool HoistingGeps;

  DenseMap<const Value *, unsigned> DFSNumber;

  BBSideEffectsSet BBSideEffects;
@@ -505,11 +502,6 @@ private: 
  bool safeToHoistScalar(const BasicBlock *HoistBB,

                         SmallPtrSetImpl<const BasicBlock *> &WL,

                         int &NBBsOnAllPaths) {

    // Enable scalar hoisting at -Oz as it is safe to hoist scalars to a place

    // where they are partially needed.

    if (OptForMinSize)

      return true;



    // Check that the hoisted expression is needed on all paths.

    if (!hoistingFromAllPaths(HoistBB, WL))

      return false;
@@ -923,13 +915,8 @@ private: 
                Intr->getIntrinsicID() == Intrinsic::assume)

              continue;

          }

          if (Call->mayHaveSideEffects()) {

            if (!OptForMinSize)

          if (Call->mayHaveSideEffects())

            break;

            // We may continue hoisting across calls which write to memory.

            if (Call->mayThrow())

              break;

          }



          if (Call->isConvergent())

            break;
@@ -971,7 +958,7 @@ public: 
    auto &MD = getAnalysis<MemoryDependenceWrapperPass>().getMemDep();

    auto &MSSA = getAnalysis<MemorySSAWrapperPass>().getMSSA();



    GVNHoist G(&DT, &AA, &MD, &MSSA, F.optForMinSize());

    GVNHoist G(&DT, &AA, &MD, &MSSA);

    return G.run(F);

  }
@@ -991,7 +978,7 @@ PreservedAnalyses GVNHoistPass::run(Function &F, FunctionAnalysisManager &AM) { 
  AliasAnalysis &AA = AM.getResult<AAManager>(F);

  MemoryDependenceResults &MD = AM.getResult<MemoryDependenceAnalysis>(F);

  MemorySSA &MSSA = AM.getResult<MemorySSAAnalysis>(F).getMSSA();

  GVNHoist G(&DT, &AA, &MD, &MSSA, F.optForMinSize());

  GVNHoist G(&DT, &AA, &MD, &MSSA);

  if (!G.run(F))

    return PreservedAnalyses::all();

llvm/test/Transforms/GVNHoist/hoist-unsafe-pr31729.ll

0 → 100644
+81 −0
Original line number Diff line number Diff line 
; RUN: opt -gvn-hoist -S < %s | FileCheck %s



; Check that urem is not hoisted.

; CHECK-LABEL: @main

; CHECK: urem

; CHECK: urem

; CHECK: urem



@g_x_s = global i32 -470211272, align 4

@g_z_s = global i32 2007237709, align 4

@g_x_u = global i32 282475249, align 4

@g_z_u = global i32 984943658, align 4

@g_m = global i32 16807, align 4

@res = common global i32 0, align 4



; Function Attrs:

define i64 @func() #0 {

entry:

  ret i64 1

}



; Function Attrs:

define i32 @main() {

entry:

  %0 = load volatile i32, i32* @g_x_s, align 4

  %1 = load volatile i32, i32* @g_z_s, align 4

  %2 = load volatile i32, i32* @g_x_u, align 4

  %3 = load volatile i32, i32* @g_z_u, align 4

  %4 = load volatile i32, i32* @g_m, align 4

  %call = call i64 @func() #4

  %conv = sext i32 %1 to i64

  %cmp = icmp ne i64 %call, %conv

  br i1 %cmp, label %if.end, label %lor.lhs.false



lor.lhs.false:

  %div = udiv i32 %4, %1

  %rem = urem i32 %0, %div

  %cmp2 = icmp eq i32 %rem, 0

  br i1 %cmp2, label %if.end, label %if.then



if.then:

  br label %cleanup



if.end:

  %call4 = call i64 @func() #4

  %conv5 = zext i32 %3 to i64

  %cmp6 = icmp ne i64 %call4, %conv5

  br i1 %cmp6, label %if.end14, label %lor.lhs.false8



lor.lhs.false8:

  %div9 = udiv i32 %4, %3

  %rem10 = urem i32 %0, %div9

  %cmp11 = icmp eq i32 %rem10, 0

  br i1 %cmp11, label %if.end14, label %if.then13



if.then13:

  br label %cleanup



if.end14:

  %call15 = call i64 @func() #4

  %cmp17 = icmp ne i64 %call15, %conv

  br i1 %cmp17, label %if.end25, label %lor.lhs.false19



lor.lhs.false19:

  %div20 = udiv i32 %4, %1

  %rem21 = urem i32 %0, %div20

  %cmp22 = icmp eq i32 %rem21, 0

  br i1 %cmp22, label %if.end25, label %if.then24



if.then24:

  br label %cleanup



if.end25:

  br label %cleanup



cleanup:

  %retval.0 = phi i32 [ 0, %if.end25 ], [ 1, %if.then24 ], [ 1, %if.then13 ], [ 1, %if.then ]

  ret i32 %retval.0

}



attributes #0 = { minsize noinline nounwind optsize uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }