diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp index a0fa884cda1da..2c9ba203fbf3d 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp @@ -2234,14 +2234,9 @@ Instruction *InstCombiner::optimizeBitCastFromPhi(CastInst &CI, PHINode *PN) { if (auto *C = dyn_cast(V)) { NewV = ConstantExpr::getBitCast(C, DestTy); } else if (auto *LI = dyn_cast(V)) { - // Explicitly perform load combine to make sure no opposing transform - // can remove the bitcast in the meantime and trigger an infinite loop. - Builder.SetInsertPoint(LI); - NewV = combineLoadToNewType(*LI, DestTy); - // Remove the old load and its use in the old phi, which itself becomes - // dead once the whole transform finishes. - replaceInstUsesWith(*LI, UndefValue::get(LI->getType())); - eraseInstFromFunction(*LI); + Builder.SetInsertPoint(LI->getNextNode()); + NewV = Builder.CreateBitCast(LI, DestTy); + Worklist.Add(LI); } else if (auto *BCI = dyn_cast(V)) { NewV = BCI->getOperand(0); } else if (auto *PrevPN = dyn_cast(V)) { diff --git a/llvm/test/Transforms/InstCombine/pr44245.ll b/llvm/test/Transforms/InstCombine/pr44245.ll deleted file mode 100644 index f75e26e87add8..0000000000000 --- a/llvm/test/Transforms/InstCombine/pr44245.ll +++ /dev/null @@ -1,192 +0,0 @@ -; NOTE: Assertions have been autogenerated by utils/update_test_checks.py -; RUN: opt -S -instcombine -instcombine-infinite-loop-threshold=2 < %s | FileCheck %s - -; This used to cause on infinite instcombine loop. - -define void @test(i1 %c) { -; CHECK-LABEL: @test( -; CHECK-NEXT: bb16: -; CHECK-NEXT: br i1 [[C:%.*]], label [[BB17:%.*]], label [[BB24:%.*]] -; CHECK: bb17: -; CHECK-NEXT: [[TMP0:%.*]] = phi i8* [ [[TMP1:%.*]], [[BB47:%.*]] ], [ undef, [[BB16:%.*]] ] -; CHECK-NEXT: store i8* [[TMP0]], i8** undef, align 8 -; CHECK-NEXT: ret void -; CHECK: bb24: -; CHECK-NEXT: br i1 [[C]], label [[BB44:%.*]], label [[BB49:%.*]] -; CHECK: bb44: -; CHECK-NEXT: [[TMP467:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb47: -; CHECK-NEXT: [[TMP1]] = phi i8* [ [[TMP2:%.*]], [[BB150:%.*]] ], [ [[TMP1221:%.*]], [[BB119:%.*]] ], [ [[TMP1032:%.*]], [[BB101:%.*]] ], [ [[TMP933:%.*]], [[BB91:%.*]] ], [ [[TMP834:%.*]], [[BB81:%.*]] ], [ [[TMP705:%.*]], [[BB67:%.*]] ], [ [[TMP586:%.*]], [[BB56:%.*]] ], [ [[TMP467]], [[BB44]] ] -; CHECK-NEXT: br label [[BB17]] -; CHECK: bb49: -; CHECK-NEXT: br i1 [[C]], label [[BB56]], label [[BB59:%.*]] -; CHECK: bb56: -; CHECK-NEXT: [[TMP586]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb59: -; CHECK-NEXT: br i1 [[C]], label [[BB67]], label [[BB71:%.*]] -; CHECK: bb67: -; CHECK-NEXT: [[TMP705]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb71: -; CHECK-NEXT: br i1 [[C]], label [[BB81]], label [[BB84:%.*]] -; CHECK: bb81: -; CHECK-NEXT: [[TMP834]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb84: -; CHECK-NEXT: br i1 [[C]], label [[BB91]], label [[BB94:%.*]] -; CHECK: bb91: -; CHECK-NEXT: [[TMP933]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb94: -; CHECK-NEXT: br i1 [[C]], label [[BB101]], label [[BB104:%.*]] -; CHECK: bb101: -; CHECK-NEXT: [[TMP1032]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb104: -; CHECK-NEXT: br i1 [[C]], label [[BB119]], label [[BB123:%.*]] -; CHECK: bb119: -; CHECK-NEXT: [[TMP1221]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb123: -; CHECK-NEXT: br i1 [[C]], label [[BB147:%.*]], label [[BB152:%.*]] -; CHECK: bb147: -; CHECK-NEXT: [[TMP1499:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: br label [[BB150]] -; CHECK: bb150: -; CHECK-NEXT: [[TMP2]] = phi i8* [ [[TMP1848:%.*]], [[BB152]] ], [ [[TMP1499]], [[BB147]] ] -; CHECK-NEXT: br label [[BB47]] -; CHECK: bb152: -; CHECK-NEXT: [[TMP1848]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16 -; CHECK-NEXT: call void undef() -; CHECK-NEXT: br label [[BB150]] -; -bb16: ; preds = %bb - br i1 %c, label %bb17, label %bb24 - -bb17: ; preds = %bb47, %bb17 - %0 = phi i8* [ %1, %bb47 ], [ undef, %bb16 ] - store i8* %0, i8** undef, align 8 - ret void - -bb24: ; preds = %bb24 - br i1 %c, label %bb44, label %bb49 - -bb44: ; preds = %bb43 - %tmp46 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb47: ; preds = %bb150, %bb119, %bb101, %bb91, %bb81, %bb67, %bb56, %bb44 - %.in1 = phi i64* [ %.in, %bb150 ], [ %tmp122, %bb119 ], [ %tmp103, %bb101 ], [ %tmp93, %bb91 ], [ %tmp83, %bb81 ], [ %tmp70, %bb67 ], [ %tmp58, %bb56 ], [ %tmp46, %bb44 ] - %1 = bitcast i64* %.in1 to i8* - br label %bb17 - -bb49: ; preds = %bb49 - br i1 %c, label %bb56, label %bb59 - -bb56: ; preds = %bb55 - %tmp58 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb59: ; preds = %bb59 - br i1 %c, label %bb67, label %bb71 - -bb67: ; preds = %bb66 - %tmp70 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb71: ; preds = %bb71 - br i1 %c, label %bb81, label %bb84 - -bb81: ; preds = %bb80 - %tmp83 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb84: ; preds = %bb84 - br i1 %c, label %bb91, label %bb94 - -bb91: ; preds = %bb90 - %tmp93 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb94: ; preds = %bb94 - br i1 %c, label %bb101, label %bb104 - -bb101: ; preds = %bb100 - %tmp103 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb104: ; preds = %bb104 - br i1 %c, label %bb119, label %bb123 - -bb119: ; preds = %bb118 - %tmp122 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb47 - -bb123: ; preds = %bb123 - br i1 %c, label %bb147, label %bb152 - -bb147: ; preds = %bb146 - %tmp149 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - br label %bb150 - -bb150: ; preds = %bb152, %bb147 - %.in = phi i64* [ %tmp184, %bb152 ], [ %tmp149, %bb147 ] - br label %bb47 - -bb152: ; preds = %bb146 - %tmp184 = load i64*, i64** inttoptr (i64 16 to i64**), align 16 - call void undef() - br label %bb150 -} - -; This used to cause an instcombine loop when the problem above was -; addressed in a non-robust fashion. - -%type_1 = type {} -%type_2 = type {} -%type_3 = type {} - -define void @test_2(i1 %c) local_unnamed_addr { -; CHECK-LABEL: @test_2( -; CHECK-NEXT: entry: -; CHECK-NEXT: br label [[WHILE_COND:%.*]] -; CHECK: while.cond: -; CHECK-NEXT: br label [[FOR_COND:%.*]] -; CHECK: for.cond: -; CHECK-NEXT: br i1 [[C:%.*]], label [[COND_TRUE133:%.*]], label [[COND_FALSE138:%.*]] -; CHECK: cond.true133: -; CHECK-NEXT: store %type_3* undef, %type_3** null, align 536870912 -; CHECK-NEXT: br label [[COND_END144:%.*]] -; CHECK: cond.false138: -; CHECK-NEXT: store %type_3* undef, %type_3** null, align 536870912 -; CHECK-NEXT: br label [[COND_END144]] -; CHECK: cond.end144: -; CHECK-NEXT: br label [[WHILE_COND]] -; -entry: - br label %while.cond - -while.cond: ; preds = %cond.end144, %entry - %link.0 = phi %type_2* [ undef, %entry ], [ %cond145, %cond.end144 ] - %os115 = bitcast %type_2* %link.0 to %type_3* - %ou116 = getelementptr inbounds %type_3, %type_3* %os115, i32 0 - %os1117 = bitcast %type_3* %ou116 to %type_1* - br label %for.cond - -for.cond: ; preds = %while.cond - br i1 %c, label %cond.true133, label %cond.false138 - -cond.true133: ; preds = %sw.epilog - %0 = load %type_2*, %type_2** undef, align 8 - br label %cond.end144 - -cond.false138: ; preds = %sw.epilog - %1 = load %type_2*, %type_2** undef, align 8 - br label %cond.end144 - -cond.end144: ; preds = %cond.false138, %cond.true133 - %cond145 = phi %type_2* [ %0, %cond.true133 ], [ %1, %cond.false138 ] - br label %while.cond -}