From 1da0da903ee818385d8ce470d14f9f9c7cdf6942 Mon Sep 17 00:00:00 2001 From: luxufan Date: Wed, 19 Apr 2023 19:57:27 +0800 Subject: [PATCH] [LVI][CVP] Don't compute CR at SelectInst Use if Cond value may not be well-defined If the condition value of SelectInst may be a poison or undef value, infer constant range at SelectInst use is in correct. See https://alive2.llvm.org/ce/z/MWMTYn Fixes: https://github.com/llvm/llvm-project/issues/62200 Differential Revision: https://reviews.llvm.org/D148709 --- llvm/lib/Analysis/LazyValueInfo.cpp | 4 +++ .../CorrelatedValuePropagation/cond-at-use.ll | 39 ++++++++++++++-------- 2 files changed, 30 insertions(+), 13 deletions(-) diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp index 7bb66f2..3491bce 100644 --- a/llvm/lib/Analysis/LazyValueInfo.cpp +++ b/llvm/lib/Analysis/LazyValueInfo.cpp @@ -1667,6 +1667,10 @@ ConstantRange LazyValueInfo::getConstantRangeAtUse(const Use &U, std::optional CondVal; auto *CurrI = cast(CurrU->getUser()); if (auto *SI = dyn_cast(CurrI)) { + // If the value is undef, a different value may be chosen in + // the select condition and at use. + if (!isGuaranteedNotToBeUndefOrPoison(SI->getCondition(), AC)) + break; if (CurrU->getOperandNo() == 1) CondVal = getValueFromCondition(V, SI->getCondition(), true); else if (CurrU->getOperandNo() == 2) diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll b/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll index 6270ca8..dbb6320 100644 --- a/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll +++ b/llvm/test/Transforms/CorrelatedValuePropagation/cond-at-use.ll @@ -7,7 +7,7 @@ declare i16 @llvm.uadd.sat.i16(i16, i16) declare i16 @llvm.umin.i16(i16, i16) declare i16 @llvm.abs.i16(i16, i1) -define i16 @sel_true_cond(i16 %x) { +define i16 @sel_true_cond(i16 noundef %x) { ; CHECK-LABEL: @sel_true_cond( ; CHECK-NEXT: [[SUB1:%.*]] = sub nuw i16 [[X:%.*]], 10 ; CHECK-NEXT: [[CMP:%.*]] = icmp uge i16 [[X]], 10 @@ -74,7 +74,7 @@ define i16 @sel_true_cond_extra_use(i16 %x) { ret i16 %sel } -define i16 @sel_true_cond_chain_speculatable(i16 %x) { +define i16 @sel_true_cond_chain_speculatable(i16 noundef %x) { ; CHECK-LABEL: @sel_true_cond_chain_speculatable( ; CHECK-NEXT: [[SUB1:%.*]] = add nuw i16 [[X:%.*]], 1 ; CHECK-NEXT: [[EXTRA:%.*]] = mul i16 [[SUB1]], 3 @@ -123,7 +123,7 @@ define i16 @sel_true_cond_longer_chain(i16 %x) { ret i16 %sel } -define i16 @sel_false_cond(i16 %x) { +define i16 @sel_false_cond(i16 noundef %x) { ; CHECK-LABEL: @sel_false_cond( ; CHECK-NEXT: [[SUB1:%.*]] = sub nuw i16 [[X:%.*]], 10 ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i16 [[X]], 10 @@ -332,7 +332,7 @@ exit: ret i16 %count } -define i16 @urem_elide(i16 %x) { +define i16 @urem_elide(i16 noundef %x) { ; CHECK-LABEL: @urem_elide( ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i16 [[X:%.*]], 42 ; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i16 [[X]], i16 24 @@ -344,7 +344,7 @@ define i16 @urem_elide(i16 %x) { ret i16 %sel } -define i16 @urem_expand(i16 %x) { +define i16 @urem_expand(i16 noundef %x) { ; CHECK-LABEL: @urem_expand( ; CHECK-NEXT: [[X_FROZEN:%.*]] = freeze i16 [[X:%.*]] ; CHECK-NEXT: [[UREM_UREM:%.*]] = sub nuw i16 [[X_FROZEN]], 42 @@ -360,7 +360,7 @@ define i16 @urem_expand(i16 %x) { ret i16 %sel } -define i16 @urem_narrow(i16 %x) { +define i16 @urem_narrow(i16 noundef %x) { ; CHECK-LABEL: @urem_narrow( ; CHECK-NEXT: [[UREM_LHS_TRUNC:%.*]] = trunc i16 [[X:%.*]] to i8 ; CHECK-NEXT: [[UREM1:%.*]] = urem i8 [[UREM_LHS_TRUNC]], 42 @@ -388,7 +388,7 @@ define i16 @urem_insufficient(i16 %x) { ret i16 %sel } -define i16 @srem_elide(i16 %x) { +define i16 @srem_elide(i16 noundef %x) { ; CHECK-LABEL: @srem_elide( ; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i16 [[X:%.*]], 42 ; CHECK-NEXT: [[CMP2:%.*]] = icmp sgt i16 [[X]], -42 @@ -404,7 +404,7 @@ define i16 @srem_elide(i16 %x) { ret i16 %sel } -define i16 @srem_narrow(i16 %x) { +define i16 @srem_narrow(i16 noundef %x) { ; CHECK-LABEL: @srem_narrow( ; CHECK-NEXT: [[SREM_LHS_TRUNC:%.*]] = trunc i16 [[X:%.*]] to i8 ; CHECK-NEXT: [[SREM1:%.*]] = srem i8 [[SREM_LHS_TRUNC]], 42 @@ -423,7 +423,7 @@ define i16 @srem_narrow(i16 %x) { ret i16 %sel } -define i16 @srem_convert(i16 %x) { +define i16 @srem_convert(i16 noundef %x) { ; CHECK-LABEL: @srem_convert( ; CHECK-NEXT: [[X_NONNEG:%.*]] = sub i16 0, [[X:%.*]] ; CHECK-NEXT: [[SREM1:%.*]] = urem i16 [[X_NONNEG]], 42 @@ -438,7 +438,7 @@ define i16 @srem_convert(i16 %x) { ret i16 %sel } -define i16 @sdiv_convert(i16 %x) { +define i16 @sdiv_convert(i16 noundef %x) { ; CHECK-LABEL: @sdiv_convert( ; CHECK-NEXT: [[X_NONNEG:%.*]] = sub i16 0, [[X:%.*]] ; CHECK-NEXT: [[SREM1:%.*]] = udiv i16 [[X_NONNEG]], 42 @@ -505,7 +505,7 @@ define i16 @umin_elide(i16 %x) { ret i16 %sel } -define i16 @ashr_convert(i16 %x, i16 %y) { +define i16 @ashr_convert(i16 noundef %x, i16 %y) { ; CHECK-LABEL: @ashr_convert( ; CHECK-NEXT: [[ASHR:%.*]] = lshr i16 [[X:%.*]], [[Y:%.*]] ; CHECK-NEXT: [[CMP:%.*]] = icmp sge i16 [[X]], 0 @@ -518,7 +518,7 @@ define i16 @ashr_convert(i16 %x, i16 %y) { ret i16 %sel } -define i32 @sext_convert(i16 %x) { +define i32 @sext_convert(i16 noundef %x) { ; CHECK-LABEL: @sext_convert( ; CHECK-NEXT: [[EXT:%.*]] = zext i16 [[X:%.*]] to i32 ; CHECK-NEXT: [[CMP:%.*]] = icmp sge i16 [[X]], 0 @@ -544,7 +544,7 @@ define i16 @infer_flags(i16 %x) { ret i16 %sel } -define i16 @and_elide(i16 %x) { +define i16 @and_elide(i16 noundef %x) { ; CHECK-LABEL: @and_elide( ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i16 [[X:%.*]], 8 ; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i16 [[X]], i16 24 @@ -555,3 +555,16 @@ define i16 @and_elide(i16 %x) { %sel = select i1 %cmp, i16 %and, i16 24 ret i16 %sel } + +define i16 @cond_value_may_not_well_defined(i16 %x) { +; CHECK-LABEL: @cond_value_may_not_well_defined( +; CHECK-NEXT: [[AND:%.*]] = and i16 [[X:%.*]], 7 +; CHECK-NEXT: [[CMP:%.*]] = icmp ult i16 [[X]], 8 +; CHECK-NEXT: [[SEL:%.*]] = select i1 [[CMP]], i16 [[AND]], i16 24 +; CHECK-NEXT: ret i16 [[SEL]] +; + %and = and i16 %x, 7 + %cmp = icmp ult i16 %x, 8 + %sel = select i1 %cmp, i16 %and, i16 24 + ret i16 %sel +} -- 2.7.4