diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h index 5d25804a684ac..2eb4fd36c5b7d 100644 --- a/llvm/include/llvm/IR/Instruction.h +++ b/llvm/include/llvm/IR/Instruction.h @@ -584,9 +584,10 @@ class Instruction : public User, dropUBImplyingAttrsAndUnknownMetadata(ArrayRef KnownIDs = {}); /// Drop any attributes or metadata that can cause immediate undefined - /// behavior. Retain other attributes/metadata on a best-effort basis. - /// This should be used when speculating instructions. - LLVM_ABI void dropUBImplyingAttrsAndMetadata(); + /// behavior. Retain other attributes/metadata on a best-effort basis, as well + /// as those passed in `Keep`. This should be used when speculating + /// instructions. + LLVM_ABI void dropUBImplyingAttrsAndMetadata(ArrayRef Keep = {}); /// Return true if this instruction has UB-implying attributes /// that can cause immediate undefined behavior. diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp index 0b7923248aa7e..c83824af38e1b 100644 --- a/llvm/lib/IR/Instruction.cpp +++ b/llvm/lib/IR/Instruction.cpp @@ -552,14 +552,18 @@ void Instruction::dropUBImplyingAttrsAndUnknownMetadata( CB->removeRetAttrs(UBImplyingAttributes); } -void Instruction::dropUBImplyingAttrsAndMetadata() { +void Instruction::dropUBImplyingAttrsAndMetadata(ArrayRef Keep) { // !annotation metadata does not impact semantics. // !range, !nonnull and !align produce poison, so they are safe to speculate. // !noundef and various AA metadata must be dropped, as it generally produces // immediate undefined behavior. - unsigned KnownIDs[] = {LLVMContext::MD_annotation, LLVMContext::MD_range, - LLVMContext::MD_nonnull, LLVMContext::MD_align}; - dropUBImplyingAttrsAndUnknownMetadata(KnownIDs); + static const unsigned KnownIDs[] = { + LLVMContext::MD_annotation, LLVMContext::MD_range, + LLVMContext::MD_nonnull, LLVMContext::MD_align}; + SmallVector KeepIDs(Keep.size() + std::size(KnownIDs)); + append_range(KeepIDs, KnownIDs); + append_range(KeepIDs, Keep); + dropUBImplyingAttrsAndUnknownMetadata(KeepIDs); } bool Instruction::hasUBImplyingAttrs() const { diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp index 1ef4fcc5fac47..6396d14e5baaf 100644 --- a/llvm/lib/Transforms/Scalar/LICM.cpp +++ b/llvm/lib/Transforms/Scalar/LICM.cpp @@ -1699,8 +1699,12 @@ static void hoist(Instruction &I, const DominatorTree *DT, const Loop *CurLoop, // The check on hasMetadataOtherThanDebugLoc is to prevent us from burning // time in isGuaranteedToExecute if we don't actually have anything to // drop. It is a compile time optimization, not required for correctness. - !SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop)) - I.dropUBImplyingAttrsAndMetadata(); + !SafetyInfo->isGuaranteedToExecute(I, DT, CurLoop)) { + if (ProfcheckDisableMetadataFixes) + I.dropUBImplyingAttrsAndMetadata(); + else + I.dropUBImplyingAttrsAndMetadata({LLVMContext::MD_prof}); + } if (isa(I)) // Move the new node to the end of the phi list in the destination block. diff --git a/llvm/test/Transforms/LICM/hoist-profdata.ll b/llvm/test/Transforms/LICM/hoist-profdata.ll new file mode 100644 index 0000000000000..18fa1b9f92e8a --- /dev/null +++ b/llvm/test/Transforms/LICM/hoist-profdata.ll @@ -0,0 +1,45 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals --version 2 +; Test that hoisting conditional branches copies the debug and profiling info +; metadata from the branch being hoisted. +; RUN: opt -S -passes=licm %s -o - | FileCheck %s + +declare i32 @foo() + +; to_hoist should get hoisted, and that should not result +; in a loss of profiling info +define i32 @hoist_select(i1 %cond, i32 %a, i32 %b) nounwind { +; CHECK-LABEL: define i32 @hoist_select +; CHECK-SAME: (i1 [[COND:%.*]], i32 [[A:%.*]], i32 [[B:%.*]]) #[[ATTR0:[0-9]+]] { +; CHECK-NEXT: entry: +; CHECK-NEXT: [[TO_HOIST:%.*]] = select i1 [[COND]], i32 [[A]], i32 [[B]], !prof [[PROF0:![0-9]+]] +; CHECK-NEXT: br label [[L0:%.*]] +; CHECK: L0: +; CHECK-NEXT: [[G:%.*]] = call i32 @foo() +; CHECK-NEXT: [[SUM:%.*]] = add i32 [[G]], [[TO_HOIST]] +; CHECK-NEXT: [[C:%.*]] = icmp eq i32 [[SUM]], 0 +; CHECK-NEXT: br i1 [[C]], label [[L0]], label [[EXIT:%.*]], !prof [[PROF1:![0-9]+]] +; CHECK: exit: +; CHECK-NEXT: [[SUM_LCSSA:%.*]] = phi i32 [ [[SUM]], [[L0]] ] +; CHECK-NEXT: ret i32 [[SUM_LCSSA]] +; +entry: + br label %L0 +L0: + %g = call i32 @foo() + %to_hoist = select i1 %cond, i32 %a, i32 %b, !prof !0 + %sum = add i32 %g, %to_hoist + %c = icmp eq i32 %sum, 0 + br i1 %c, label %L0, label %exit, !prof !1 + +exit: + ret i32 %sum +} + +!0 = !{!"branch_weights", i32 2, i32 5} +!1 = !{!"branch_weights", i32 101, i32 189} +;. +; CHECK: attributes #[[ATTR0]] = { nounwind } +;. +; CHECK: [[PROF0]] = !{!"branch_weights", i32 2, i32 5} +; CHECK: [[PROF1]] = !{!"branch_weights", i32 101, i32 189} +;.