diff --git a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp --- a/llvm/lib/Transforms/Scalar/LoopDeletion.cpp +++ b/llvm/lib/Transforms/Scalar/LoopDeletion.cpp @@ -85,7 +85,9 @@ // This includes instructions that could write to memory, and loads that are // marked volatile. for (auto &I : L->blocks()) - if (any_of(*I, [](Instruction &I) { return I.mayHaveSideEffects(); })) + if (any_of(*I, [](Instruction &I) { + return I.mayHaveSideEffects() && !I.isDroppable(); + })) return false; return true; } diff --git a/llvm/test/Transforms/LoopDeletion/assume.ll b/llvm/test/Transforms/LoopDeletion/assume.ll new file mode 100644 --- /dev/null +++ b/llvm/test/Transforms/LoopDeletion/assume.ll @@ -0,0 +1,40 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt %s -passes=loop-deletion -S | FileCheck %s --check-prefixes=CHECK + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +%class.Loc.95 = type { %class.Domain.96 } +%class.Domain.96 = type { %class.DomainBase.97 } +%class.DomainBase.97 = type { [3 x %struct.WrapNoInit] } +%struct.WrapNoInit = type { %class.Loc } +%class.Loc = type { %class.Domain.67 } +%class.Domain.67 = type { %class.DomainBase.68 } +%class.DomainBase.68 = type { i32 } + +define dso_local void @_ZSt8_DestroyIP3LocILi3EES1_EvT_S3_RSaIT0_E(%class.Loc.95* %0) #0 { +; CHECK-LABEL: @_ZSt8_DestroyIP3LocILi3EES1_EvT_S3_RSaIT0_E( +; CHECK-NEXT: br label [[_ZST8_DESTROYIP3LOCILI3EEEVT_S3__EXIT:%.*]] +; CHECK: _ZSt8_DestroyIP3LocILi3EEEvT_S3_.exit: +; CHECK-NEXT: ret void +; + br label %2 + +2: ; preds = %4, %1 + %.0.i.i = phi %class.Loc.95* [ undef, %1 ], [ %5, %4 ] + %3 = icmp ne %class.Loc.95* %.0.i.i, %0 + br i1 %3, label %4, label %_ZSt8_DestroyIP3LocILi3EEEvT_S3_.exit + +4: ; preds = %2 + call void @llvm.assume(i1 true) [ "align"(%class.Loc.95* %.0.i.i, i64 4) ] + %5 = getelementptr inbounds %class.Loc.95, %class.Loc.95* %.0.i.i, i32 1 + br label %2 + +_ZSt8_DestroyIP3LocILi3EEEvT_S3_.exit: ; preds = %2 + ret void +} + +declare void @llvm.assume(i1) #1 + +attributes #0 = { "target-cpu"="x86-64" } +attributes #1 = { willreturn readnone norecurse nocapture nofree }