diff --git a/llvm/lib/Target/BPF/BPFISelLowering.cpp b/llvm/lib/Target/BPF/BPFISelLowering.cpp --- a/llvm/lib/Target/BPF/BPFISelLowering.cpp +++ b/llvm/lib/Target/BPF/BPFISelLowering.cpp @@ -168,6 +168,7 @@ MaxStoresPerMemset = MaxStoresPerMemsetOptSize = 0; MaxStoresPerMemcpy = MaxStoresPerMemcpyOptSize = 0; MaxStoresPerMemmove = MaxStoresPerMemmoveOptSize = 0; + MaxLoadsPerMemcmp = 0; } else { // inline memcpy() for kernel to see explicit copy unsigned CommonMaxStores = @@ -176,6 +177,7 @@ MaxStoresPerMemset = MaxStoresPerMemsetOptSize = CommonMaxStores; MaxStoresPerMemcpy = MaxStoresPerMemcpyOptSize = CommonMaxStores; MaxStoresPerMemmove = MaxStoresPerMemmoveOptSize = CommonMaxStores; + MaxLoadsPerMemcmp = MaxLoadsPerMemcmpOptSize = CommonMaxStores; } // CPU/Feature control diff --git a/llvm/lib/Target/BPF/BPFTargetTransformInfo.h b/llvm/lib/Target/BPF/BPFTargetTransformInfo.h --- a/llvm/lib/Target/BPF/BPFTargetTransformInfo.h +++ b/llvm/lib/Target/BPF/BPFTargetTransformInfo.h @@ -71,6 +71,15 @@ Opd2Info, Opd1PropInfo, Opd2PropInfo); } + + TTI::MemCmpExpansionOptions enableMemCmpExpansion(bool OptSize, + bool IsZeroCmp) const { + TTI::MemCmpExpansionOptions Options; + Options.LoadSizes = {8, 4, 2, 1}; + Options.MaxNumLoads = TLI->getMaxExpandSizeMemcmp(OptSize); + return Options; + } + }; } // end namespace llvm diff --git a/llvm/test/CodeGen/BPF/memcmp.ll b/llvm/test/CodeGen/BPF/memcmp.ll new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/BPF/memcmp.ll @@ -0,0 +1,72 @@ +; RUN: llc -march=bpfel < %s | FileCheck %s +; RUN: llc -march=bpfel -mcpu=v3 < %s | FileCheck %s +; +; Source code: +; /* set aligned 4 to minimize the number of loads */ +; struct build_id { +; unsigned char id[20]; +; } __attribute__((aligned(4))); +; +; /* try to compute a local build_id */ +; void bar1(void *); +; +; /* the global build_id to compare */ +; struct build_id id2; +; +; int foo() +; { +; struct build_id id1; +; +; bar1(&id1); +; return __builtin_memcmp(&id1, &id2, sizeof(id1)) == 0; +; } +; Compilation flags: +; clang -target bpf -S -O2 t.c -emit-llvm + + +%struct.build_id = type { [20 x i8] } + +@id2 = dso_local global %struct.build_id zeroinitializer, align 4 + +; Function Attrs: nounwind +define dso_local i32 @foo() local_unnamed_addr #0 { +entry: + %id11 = alloca [20 x i8], align 4 + %id11.sub = getelementptr inbounds [20 x i8], [20 x i8]* %id11, i64 0, i64 0 + call void @llvm.lifetime.start.p0i8(i64 20, i8* nonnull %id11.sub) #4 + call void @bar1(i8* noundef nonnull %id11.sub) #4 + %call = call i32 @memcmp(i8* noundef nonnull dereferenceable(20) %id11.sub, i8* noundef nonnull dereferenceable(20) getelementptr inbounds (%struct.build_id, %struct.build_id* @id2, i64 0, i32 0, i64 0), i64 noundef 20) #4 + %cmp = icmp eq i32 %call, 0 + %conv = zext i1 %cmp to i32 + call void @llvm.lifetime.end.p0i8(i64 20, i8* nonnull %id11.sub) #4 + ret i32 %conv +} + +; CHECK: *(u32 *)(r1 + 0) +; CHECK: *(u32 *)(r10 - 20) +; CHECK: *(u32 *)(r10 - 12) +; CHECK: *(u32 *)(r1 + 8) + +; Function Attrs: argmemonly mustprogress nofree nosync nounwind willreturn +declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1 + +declare dso_local void @bar1(i8* noundef) local_unnamed_addr #2 + +; Function Attrs: argmemonly mustprogress nofree nounwind readonly willreturn +declare dso_local i32 @memcmp(i8* nocapture noundef, i8* nocapture noundef, i64 noundef) local_unnamed_addr #3 + +; Function Attrs: argmemonly mustprogress nofree nosync nounwind willreturn +declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1 + +attributes #0 = { nounwind "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" } +attributes #1 = { argmemonly mustprogress nofree nosync nounwind willreturn } +attributes #2 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" } +attributes #3 = { argmemonly mustprogress nofree nounwind readonly willreturn "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" } +attributes #4 = { nounwind } + +!llvm.module.flags = !{!0, !1} +!llvm.ident = !{!2} + +!0 = !{i32 1, !"wchar_size", i32 4} +!1 = !{i32 7, !"frame-pointer", i32 2} +!2 = !{!"clang version 15.0.0 (https://github.com/llvm/llvm-project.git dea65874b2505f8f5e8e51fd8cad6908feb375ec)"}