[llvm-branch-commits] [llvm] 081c255 - [ValueTracking] Let isGuaranteedNotToBeUndefOrPoison use canCreateUndefOrPoison

Hans Wennborg via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Mon Jul 20 06:36:01 PDT 2020


Ah, sorry. I got confused by the email, which doesn't actually say
which branch the commit went to  :-/
Thanks for clarifying!

On Mon, Jul 20, 2020 at 11:35 AM Nikita Popov <nikita.ppv at gmail.com> wrote:
>
> Hi Hans,
>
> I accidentally pushed a branch to the upstream repo instead of a fork. I've deleted it shortly after. It has no relation to the release branch.
>
> Regards,
> Nikita
>
> On Mon, Jul 20, 2020 at 11:24 AM Hans Wennborg <hans at chromium.org> wrote:
>>
>> Hi Nikita,
>>
>> Where did this come from? The commit message doesn't mention a code
>> review or if this is a cherry-pick from something on trunk.
>>
>> Please always check with me before pushing anything to the release branch.
>>
>> Thanks,
>> Hans
>>
>> On Sun, Jul 19, 2020 at 7:27 PM Nikita Popov via llvm-branch-commits
>> <llvm-branch-commits at lists.llvm.org> wrote:
>> >
>> >
>> > Author: Nikita Popov
>> > Date: 2020-07-19T19:26:45+02:00
>> > New Revision: 081c25553185740fde7d93d2a32ef4e87ae480aa
>> >
>> > URL: https://github.com/llvm/llvm-project/commit/081c25553185740fde7d93d2a32ef4e87ae480aa
>> > DIFF: https://github.com/llvm/llvm-project/commit/081c25553185740fde7d93d2a32ef4e87ae480aa.diff
>> >
>> > LOG: [ValueTracking] Let isGuaranteedNotToBeUndefOrPoison use canCreateUndefOrPoison
>> >
>> > Added:
>> >
>> >
>> > Modified:
>> >     llvm/include/llvm/Analysis/ValueTracking.h
>> >     llvm/lib/Analysis/ValueTracking.cpp
>> >     llvm/test/Transforms/DivRemPairs/PowerPC/div-expanded-rem-pair.ll
>> >     llvm/test/Transforms/DivRemPairs/PowerPC/div-rem-pairs.ll
>> >     llvm/test/Transforms/InstSimplify/freeze-noundef.ll
>> >     llvm/test/Transforms/InstSimplify/freeze.ll
>> >
>> > Removed:
>> >
>> >
>> >
>> > ################################################################################
>> > diff  --git a/llvm/include/llvm/Analysis/ValueTracking.h b/llvm/include/llvm/Analysis/ValueTracking.h
>> > index 178f61563cd7..ce5aea2e8d34 100644
>> > --- a/llvm/include/llvm/Analysis/ValueTracking.h
>> > +++ b/llvm/include/llvm/Analysis/ValueTracking.h
>> > @@ -607,7 +607,8 @@ class Value;
>> >    bool canCreatePoison(const Operator *Op);
>> >
>> >    /// Return true if this function can prove that V is never undef value
>> > -  /// or poison value.
>> > +  /// or poison value. If V is an aggregate value or vector, check whether all
>> > +  /// elements (except padding) are not undef or poison.
>> >    /// Note that this is
>> > diff erent from canCreateUndefOrPoison because the
>> >    /// function assumes Op's operands are not poison/undef.
>> >    ///
>> >
>> > diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
>> > index 380022c10ace..ed22718d866e 100644
>> > --- a/llvm/lib/Analysis/ValueTracking.cpp
>> > +++ b/llvm/lib/Analysis/ValueTracking.cpp
>> > @@ -4779,23 +4779,13 @@ bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V,
>> >    if (Depth >= MaxDepth)
>> >      return false;
>> >
>> > -  // If the value is a freeze instruction, then it can never
>> > -  // be undef or poison.
>> > -  if (isa<FreezeInst>(V))
>> > -    return true;
>> > -  // TODO: Some instructions are guaranteed to return neither undef
>> > -  // nor poison if their arguments are not poison/undef.
>> > -
>> > -  if (auto *A = dyn_cast<Argument>(V)) {
>> > -    // NoUndef does not guarantee that paddings are not undef.
>> > +  if (const auto *A = dyn_cast<Argument>(V)) {
>> >      if (A->hasAttribute(Attribute::NoUndef))
>> >        return true;
>> >    }
>> >
>> >    if (auto *C = dyn_cast<Constant>(V)) {
>> > -    // TODO: We can analyze ConstExpr by opcode to determine if there is any
>> > -    //       possibility of poison.
>> > -    if (isa<UndefValue>(C) || isa<ConstantExpr>(C))
>> > +    if (isa<UndefValue>(C))
>> >        return false;
>> >
>> >      if (isa<ConstantInt>(C) || isa<GlobalVariable>(C) || isa<ConstantFP>(V) ||
>> > @@ -4804,9 +4794,6 @@ bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V,
>> >
>> >      if (C->getType()->isVectorTy())
>> >        return !C->containsUndefElement() && !C->containsConstantExpression();
>> > -
>> > -    // TODO: Recursively analyze aggregates or other constants.
>> > -    return false;
>> >    }
>> >
>> >    // Strip cast operations from a pointer value.
>> > @@ -4826,31 +4813,25 @@ bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V,
>> >      return isGuaranteedNotToBeUndefOrPoison(V, CtxI, DT, Depth + 1);
>> >    };
>> >
>> > -  if (auto *I = dyn_cast<Instruction>(V)) {
>> > -    switch (I->getOpcode()) {
>> > -    case Instruction::GetElementPtr: {
>> > -      auto *GEPI = dyn_cast<GetElementPtrInst>(I);
>> > -      if (!GEPI->isInBounds() && llvm::all_of(GEPI->operands(), OpCheck))
>> > -        return true;
>> > -      break;
>> > -    }
>> > -    case Instruction::FCmp: {
>> > -      auto *FI = dyn_cast<FCmpInst>(I);
>> > -      if (FI->getFastMathFlags().none() &&
>> > -          llvm::all_of(FI->operands(), OpCheck))
>> > -        return true;
>> > -      break;
>> > -    }
>> > -    case Instruction::BitCast:
>> > -    case Instruction::PHI:
>> > -    case Instruction::ICmp:
>> > -      if (llvm::all_of(I->operands(), OpCheck))
>> > +  if (auto *Opr = dyn_cast<Operator>(V)) {
>> > +    // If the value is a freeze instruction, then it can never
>> > +    // be undef or poison.
>> > +    if (isa<FreezeInst>(V))
>> > +      return true;
>> > +
>> > +    if (const auto *CB = dyn_cast<CallBase>(V)) {
>> > +      if (CB->hasRetAttr(Attribute::NoUndef))
>> >          return true;
>> > -      break;
>> > -    default:
>> > -      break;
>> >      }
>> >
>> > +    if (canCreateUndefOrPoison(Opr))
>> > +      return false;
>> > +
>> > +    if (all_of(Opr->operands(), OpCheck))
>> > +      return true;
>> > +  }
>> > +
>> > +  if (auto *I = dyn_cast<Instruction>(V)) {
>> >      if (programUndefinedIfPoison(I) && I->getType()->isIntegerTy(1))
>> >        // Note: once we have an agreement that poison is a value-wise concept,
>> >        // we can remove the isIntegerTy(1) constraint.
>> >
>> > diff  --git a/llvm/test/Transforms/DivRemPairs/PowerPC/div-expanded-rem-pair.ll b/llvm/test/Transforms/DivRemPairs/PowerPC/div-expanded-rem-pair.ll
>> > index 4b640b98e302..277d3de7c712 100644
>> > --- a/llvm/test/Transforms/DivRemPairs/PowerPC/div-expanded-rem-pair.ll
>> > +++ b/llvm/test/Transforms/DivRemPairs/PowerPC/div-expanded-rem-pair.ll
>> > @@ -106,12 +106,11 @@ define i32 @srem_of_srem_unexpanded(i32 %X, i32 %Y, i32 %Z) {
>> >  ; CHECK-NEXT:    [[T2:%.*]] = mul nsw i32 [[T0]], [[T1]]
>> >  ; CHECK-NEXT:    [[TMP1:%.*]] = mul i32 [[T1]], [[T0_FROZEN]]
>> >  ; CHECK-NEXT:    [[T3_DECOMPOSED:%.*]] = sub i32 [[X_FROZEN]], [[TMP1]]
>> > -; CHECK-NEXT:    [[T3_DECOMPOSED_FROZEN:%.*]] = freeze i32 [[T3_DECOMPOSED]]
>> >  ; CHECK-NEXT:    [[Y_FROZEN:%.*]] = freeze i32 [[Y]]
>> > -; CHECK-NEXT:    [[T4:%.*]] = sdiv i32 [[T3_DECOMPOSED_FROZEN]], [[Y_FROZEN]]
>> > +; CHECK-NEXT:    [[T4:%.*]] = sdiv i32 [[T3_DECOMPOSED]], [[Y_FROZEN]]
>> >  ; CHECK-NEXT:    [[T5:%.*]] = mul nsw i32 [[T4]], [[Y]]
>> >  ; CHECK-NEXT:    [[TMP2:%.*]] = mul i32 [[T4]], [[Y_FROZEN]]
>> > -; CHECK-NEXT:    [[T6_DECOMPOSED:%.*]] = sub i32 [[T3_DECOMPOSED_FROZEN]], [[TMP2]]
>> > +; CHECK-NEXT:    [[T6_DECOMPOSED:%.*]] = sub i32 [[T3_DECOMPOSED]], [[TMP2]]
>> >  ; CHECK-NEXT:    ret i32 [[T6_DECOMPOSED]]
>> >  ;
>> >    %t0 = mul nsw i32 %Z, %Y
>> >
>> > diff  --git a/llvm/test/Transforms/DivRemPairs/PowerPC/div-rem-pairs.ll b/llvm/test/Transforms/DivRemPairs/PowerPC/div-rem-pairs.ll
>> > index 3692d7d224f1..9e6d85d9920a 100644
>> > --- a/llvm/test/Transforms/DivRemPairs/PowerPC/div-rem-pairs.ll
>> > +++ b/llvm/test/Transforms/DivRemPairs/PowerPC/div-rem-pairs.ll
>> > @@ -175,12 +175,11 @@ define i32 @srem_of_srem_unexpanded(i32 %X, i32 %Y, i32 %Z) {
>> >  ; CHECK-NEXT:    [[T2:%.*]] = mul nsw i32 [[T0]], [[T1]]
>> >  ; CHECK-NEXT:    [[TMP1:%.*]] = mul i32 [[T1]], [[T0_FROZEN]]
>> >  ; CHECK-NEXT:    [[T3_DECOMPOSED:%.*]] = sub i32 [[X_FROZEN]], [[TMP1]]
>> > -; CHECK-NEXT:    [[T3_DECOMPOSED_FROZEN:%.*]] = freeze i32 [[T3_DECOMPOSED]]
>> >  ; CHECK-NEXT:    [[Y_FROZEN:%.*]] = freeze i32 [[Y]]
>> > -; CHECK-NEXT:    [[T4:%.*]] = sdiv i32 [[T3_DECOMPOSED_FROZEN]], [[Y_FROZEN]]
>> > +; CHECK-NEXT:    [[T4:%.*]] = sdiv i32 [[T3_DECOMPOSED]], [[Y_FROZEN]]
>> >  ; CHECK-NEXT:    [[T5:%.*]] = mul nsw i32 [[T4]], [[Y]]
>> >  ; CHECK-NEXT:    [[TMP2:%.*]] = mul i32 [[T4]], [[Y_FROZEN]]
>> > -; CHECK-NEXT:    [[T6_DECOMPOSED:%.*]] = sub i32 [[T3_DECOMPOSED_FROZEN]], [[TMP2]]
>> > +; CHECK-NEXT:    [[T6_DECOMPOSED:%.*]] = sub i32 [[T3_DECOMPOSED]], [[TMP2]]
>> >  ; CHECK-NEXT:    ret i32 [[T6_DECOMPOSED]]
>> >  ;
>> >    %t0 = mul nsw i32 %Z, %Y
>> >
>> > diff  --git a/llvm/test/Transforms/InstSimplify/freeze-noundef.ll b/llvm/test/Transforms/InstSimplify/freeze-noundef.ll
>> > index 424477891058..f2e897b507e3 100644
>> > --- a/llvm/test/Transforms/InstSimplify/freeze-noundef.ll
>> > +++ b/llvm/test/Transforms/InstSimplify/freeze-noundef.ll
>> > @@ -19,12 +19,10 @@ define i1 @icmp(i8 noundef %x, i8 noundef %y) {
>> >    ret i1 %f
>> >  }
>> >
>> > -; TODO: should look into binary operations
>> >  define i1 @or(i1 noundef %x, i1 noundef %x2) {
>> >  ; CHECK-LABEL: @or(
>> >  ; CHECK-NEXT:    [[Y:%.*]] = or i1 [[X:%.*]], [[X2:%.*]]
>> > -; CHECK-NEXT:    [[Z:%.*]] = freeze i1 [[Y]]
>> > -; CHECK-NEXT:    ret i1 [[Z]]
>> > +; CHECK-NEXT:    ret i1 [[Y]]
>> >  ;
>> >    %y = or i1 %x, %x2
>> >    %z = freeze i1 %y
>> > @@ -42,12 +40,10 @@ define i1 @or2(i1 noundef %x, i1 %x2) {
>> >    ret i1 %z
>> >  }
>> >
>> > -; TODO: should look into binary operations
>> >  define i8 @add(i8 noundef %x) {
>> >  ; CHECK-LABEL: @add(
>> >  ; CHECK-NEXT:    [[Y:%.*]] = add i8 [[X:%.*]], 1
>> > -; CHECK-NEXT:    [[Z:%.*]] = freeze i8 [[Y]]
>> > -; CHECK-NEXT:    ret i8 [[Z]]
>> > +; CHECK-NEXT:    ret i8 [[Y]]
>> >  ;
>> >    %y = add i8 %x, 1
>> >    %z = freeze i8 %y
>> > @@ -77,21 +73,18 @@ define {i8, i32} @aggr({i8, i32} noundef %x) {
>> >  define i32 @extract({i8, i32} noundef %x) {
>> >  ; CHECK-LABEL: @extract(
>> >  ; CHECK-NEXT:    [[Y:%.*]] = extractvalue { i8, i32 } [[X:%.*]], 1
>> > -; CHECK-NEXT:    [[Z:%.*]] = freeze i32 [[Y]]
>> > -; CHECK-NEXT:    ret i32 [[Z]]
>> > +; CHECK-NEXT:    ret i32 [[Y]]
>> >  ;
>> >    %y = extractvalue {i8, i32} %x, 1
>> >    %z = freeze i32 %y
>> >    ret i32 %z
>> >  }
>> >
>> > -; TODO: should look into extract operations
>> >  define i32 @extract2({i8, {i8, i32}} noundef %x) {
>> >  ; CHECK-LABEL: @extract2(
>> >  ; CHECK-NEXT:    [[Y:%.*]] = extractvalue { i8, { i8, i32 } } [[X:%.*]], 1
>> >  ; CHECK-NEXT:    [[Z:%.*]] = extractvalue { i8, i32 } [[Y]], 1
>> > -; CHECK-NEXT:    [[W:%.*]] = freeze i32 [[Z]]
>> > -; CHECK-NEXT:    ret i32 [[W]]
>> > +; CHECK-NEXT:    ret i32 [[Z]]
>> >  ;
>> >    %y = extractvalue {i8, {i8, i32}} %x, 1
>> >    %z = extractvalue {i8, i32} %y, 1
>> >
>> > diff  --git a/llvm/test/Transforms/InstSimplify/freeze.ll b/llvm/test/Transforms/InstSimplify/freeze.ll
>> > index 306f293f7be7..8659687f07e7 100644
>> > --- a/llvm/test/Transforms/InstSimplify/freeze.ll
>> > +++ b/llvm/test/Transforms/InstSimplify/freeze.ll
>> > @@ -116,13 +116,28 @@ define <2 x float> @constvector_FP_noopt() {
>> >
>> >  define float @constant_expr() {
>> >  ; CHECK-LABEL: @constant_expr(
>> > -; CHECK-NEXT:    [[R:%.*]] = freeze float bitcast (i32 ptrtoint (i16* @g to i32) to float)
>> > -; CHECK-NEXT:    ret float [[R]]
>> > +; CHECK-NEXT:    ret float bitcast (i32 ptrtoint (i16* @g to i32) to float)
>> >  ;
>> >    %r = freeze float bitcast (i32 ptrtoint (i16* @g to i32) to float)
>> >    ret float %r
>> >  }
>> >
>> > +define i8* @constant_expr2() {
>> > +; CHECK-LABEL: @constant_expr2(
>> > +; CHECK-NEXT:    ret i8* bitcast (i16* @g to i8*)
>> > +;
>> > +  %r = freeze i8* bitcast (i16* @g to i8*)
>> > +  ret i8* %r
>> > +}
>> > +
>> > +define i32* @constant_expr3() {
>> > +; CHECK-LABEL: @constant_expr3(
>> > +; CHECK-NEXT:    ret i32* getelementptr (i32, i32* @glb, i64 3)
>> > +;
>> > +  %r = freeze i32* getelementptr (i32, i32* @glb, i64 3)
>> > +  ret i32* %r
>> > +}
>> > +
>> >  ; Negative test
>> >
>> >  define <2 x i31> @vector_element_constant_expr() {
>> > @@ -136,7 +151,7 @@ define <2 x i31> @vector_element_constant_expr() {
>> >
>> >  define void @alloca() {
>> >  ; CHECK-LABEL: @alloca(
>> > -; CHECK-NEXT:    [[P:%.*]] = alloca i8
>> > +; CHECK-NEXT:    [[P:%.*]] = alloca i8, align 1
>> >  ; CHECK-NEXT:    call void @f3(i8* [[P]])
>> >  ; CHECK-NEXT:    ret void
>> >  ;
>> > @@ -148,7 +163,7 @@ define void @alloca() {
>> >
>> >  define i8* @gep() {
>> >  ; CHECK-LABEL: @gep(
>> > -; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8]
>> > +; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8], align 1
>> >  ; CHECK-NEXT:    [[Q:%.*]] = getelementptr [4 x i8], [4 x i8]* [[P]], i32 0, i32 6
>> >  ; CHECK-NEXT:    ret i8* [[Q]]
>> >  ;
>> > @@ -171,7 +186,7 @@ define i8* @gep_noopt(i32 %arg) {
>> >
>> >  define i8* @gep_inbounds() {
>> >  ; CHECK-LABEL: @gep_inbounds(
>> > -; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8]
>> > +; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8], align 1
>> >  ; CHECK-NEXT:    [[Q:%.*]] = getelementptr inbounds [4 x i8], [4 x i8]* [[P]], i32 0, i32 0
>> >  ; CHECK-NEXT:    ret i8* [[Q]]
>> >  ;
>> > @@ -183,7 +198,7 @@ define i8* @gep_inbounds() {
>> >
>> >  define i8* @gep_inbounds_noopt(i32 %arg) {
>> >  ; CHECK-LABEL: @gep_inbounds_noopt(
>> > -; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8]
>> > +; CHECK-NEXT:    [[P:%.*]] = alloca [4 x i8], align 1
>> >  ; CHECK-NEXT:    [[Q:%.*]] = getelementptr inbounds [4 x i8], [4 x i8]* [[P]], i32 0, i32 [[ARG:%.*]]
>> >  ; CHECK-NEXT:    [[Q2:%.*]] = freeze i8* [[Q]]
>> >  ; CHECK-NEXT:    ret i8* [[Q2]]
>> >
>> >
>> >
>> > _______________________________________________
>> > llvm-branch-commits mailing list
>> > llvm-branch-commits at lists.llvm.org
>> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits


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