[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 02:24:36 PDT 2020
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]]
>
>
>
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