From: Piotr Padlewski Date: Wed, 12 Apr 2017 20:45:12 +0000 (+0000) Subject: Remove readnone from invariant.group.barrier X-Git-Tag: llvmorg-5.0.0-rc1~7903 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=04aee46779f062ed45245b9b675d1b3bd4224ae3;p=platform%2Fupstream%2Fllvm.git Remove readnone from invariant.group.barrier Summary: Readnone attribute would cause CSE of two barriers with the same argument, which is invalid by example: struct Base { virtual int foo() { return 42; } }; struct Derived1 : Base { int foo() override { return 50; } }; struct Derived2 : Base { int foo() override { return 100; } }; void foo() { Base *x = new Base{}; new (x) Derived1{}; int a = std::launder(x)->foo(); new (x) Derived2{}; int b = std::launder(x)->foo(); } Here 2 calls of std::launder will produce @llvm.invariant.group.barrier, which would be merged into one call, causing devirtualization to devirtualize second call into Derived1::foo() instead of Derived2::foo() Reviewers: chandlerc, dberlin, hfinkel Subscribers: llvm-commits, rsmith, amharc Differential Revision: https://reviews.llvm.org/D31531 llvm-svn: 300101 --- diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td index 5b796e7..309b214 100644 --- a/llvm/include/llvm/IR/Intrinsics.td +++ b/llvm/include/llvm/IR/Intrinsics.td @@ -615,9 +615,16 @@ def int_invariant_end : Intrinsic<[], llvm_anyptr_ty], [IntrArgMemOnly, NoCapture<2>]>; +// invariant.group.barrier can't be marked with 'readnone' (IntrNoMem), +// because it would cause CSE of two barriers with the same argument. +// Readonly and argmemonly says that barrier only reads its argument and +// it can be CSE only if memory didn't change between 2 barriers call, +// which is valid. +// The argument also can't be marked with 'returned' attribute, because +// it would remove barrier. def int_invariant_group_barrier : Intrinsic<[llvm_ptr_ty], [llvm_ptr_ty], - [IntrNoMem]>; + [IntrReadMem, IntrArgMemOnly]>; //===------------------------ Stackmap Intrinsics -------------------------===// // diff --git a/llvm/test/Analysis/MemorySSA/invariant-groups.ll b/llvm/test/Analysis/MemorySSA/invariant-groups.ll index 6e94ae1..26a0a32 100644 --- a/llvm/test/Analysis/MemorySSA/invariant-groups.ll +++ b/llvm/test/Analysis/MemorySSA/invariant-groups.ll @@ -16,6 +16,8 @@ define i32 @foo(i32* %a) { store i32 1, i32* @g, align 4 %1 = bitcast i32* %a to i8* +; CHECK: MemoryUse(2) +; CHECK-NEXT: %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a32 = bitcast i8* %a8 to i32* @@ -33,6 +35,8 @@ define i32 @skipBarrier(i32* %a) { store i32 0, i32* %a, align 4, !invariant.group !0 %1 = bitcast i32* %a to i8* +; CHECK: MemoryUse(1) +; CHECK-NEXT: %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a32 = bitcast i8* %a8 to i32* @@ -50,6 +54,8 @@ define i32 @skipBarrier2(i32* %a) { %v = load i32, i32* %a, align 4, !invariant.group !0 %1 = bitcast i32* %a to i8* +; CHECK: MemoryUse(liveOnEntry) +; CHECK-NEXT: %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a32 = bitcast i8* %a8 to i32* @@ -79,6 +85,8 @@ define i32 @handleInvariantGroups(i32* %a) { ; CHECK-NEXT: store i32 1 store i32 1, i32* @g, align 4 %1 = bitcast i32* %a to i8* +; CHECK: MemoryUse(2) +; CHECK-NEXT: %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a8 = call i8* @llvm.invariant.group.barrier(i8* %1) %a32 = bitcast i8* %a8 to i32* @@ -135,6 +143,9 @@ entry: ; CHECK: 2 = MemoryDef(1) ; CHECK-NEXT: call void @clobber call void @clobber8(i8* %p) + +; CHECK: MemoryUse(2) +; CHECK-NEXT: %after = call i8* @llvm.invariant.group.barrier(i8* %p) %after = call i8* @llvm.invariant.group.barrier(i8* %p) br i1 undef, label %Loop.Body, label %Loop.End @@ -179,6 +190,9 @@ entry: ; CHECK: 2 = MemoryDef(1) ; CHECK-NEXT: call void @clobber call void @clobber8(i8* %p) + +; CHECK: MemoryUse(2) +; CHECK-NEXT: %after = call i8* @llvm.invariant.group.barrier(i8* %p) %after = call i8* @llvm.invariant.group.barrier(i8* %p) br i1 undef, label %Loop.Body, label %Loop.End @@ -238,6 +252,8 @@ entry: ; CHECK: 2 = MemoryDef(1) ; CHECK-NEXT: call void @clobber call void @clobber8(i8* %p) +; CHECK: MemoryUse(2) +; CHECK-NEXT: %after = call i8* @llvm.invariant.group.barrier(i8* %p) %after = call i8* @llvm.invariant.group.barrier(i8* %p) br i1 undef, label %Loop.Pre, label %Loop.End diff --git a/llvm/test/Other/invariant.group.barrier.ll b/llvm/test/Other/invariant.group.barrier.ll new file mode 100644 index 0000000..5b9b54f --- /dev/null +++ b/llvm/test/Other/invariant.group.barrier.ll @@ -0,0 +1,62 @@ +; RUN: opt -S -early-cse < %s | FileCheck %s +; RUN: opt -S -gvn < %s | FileCheck %s +; RUN: opt -S -newgvn < %s | FileCheck %s +; RUN: opt -S -O3 < %s | FileCheck %s + +; These tests checks if passes with CSE functionality can do CSE on +; invariant.group.barrier, that is prohibited if there is a memory clobber +; between barriers call. + +; CHECK-LABEL: define i8 @optimizable() +define i8 @optimizable() { +entry: + %ptr = alloca i8 + store i8 42, i8* %ptr, !invariant.group !0 +; CHECK: call i8* @llvm.invariant.group.barrier + %ptr2 = call i8* @llvm.invariant.group.barrier(i8* %ptr) +; CHECK-NOT: call i8* @llvm.invariant.group.barrier + %ptr3 = call i8* @llvm.invariant.group.barrier(i8* %ptr) +; CHECK: call void @clobber(i8* {{.*}}%ptr) + call void @clobber(i8* %ptr) + +; CHECK: call void @use(i8* {{.*}}%ptr2) + call void @use(i8* %ptr2) +; CHECK: call void @use(i8* {{.*}}%ptr2) + call void @use(i8* %ptr3) +; CHECK: load i8, i8* %ptr2, {{.*}}!invariant.group + %v = load i8, i8* %ptr3, !invariant.group !0 + + ret i8 %v +} + +; CHECK-LABEL: define i8 @unoptimizable() +define i8 @unoptimizable() { +entry: + %ptr = alloca i8 + store i8 42, i8* %ptr, !invariant.group !0 +; CHECK: call i8* @llvm.invariant.group.barrier + %ptr2 = call i8* @llvm.invariant.group.barrier(i8* %ptr) + call void @clobber(i8* %ptr) +; CHECK: call i8* @llvm.invariant.group.barrier + %ptr3 = call i8* @llvm.invariant.group.barrier(i8* %ptr) +; CHECK: call void @clobber(i8* {{.*}}%ptr) + call void @clobber(i8* %ptr) +; CHECK: call void @use(i8* {{.*}}%ptr2) + call void @use(i8* %ptr2) +; CHECK: call void @use(i8* {{.*}}%ptr3) + call void @use(i8* %ptr3) +; CHECK: load i8, i8* %ptr3, {{.*}}!invariant.group + %v = load i8, i8* %ptr3, !invariant.group !0 + + ret i8 %v +} + +declare void @use(i8* readonly) + +declare void @clobber(i8*) +; CHECK: Function Attrs: argmemonly nounwind readonly +; CHECK-NEXT: declare i8* @llvm.invariant.group.barrier(i8*) +declare i8* @llvm.invariant.group.barrier(i8*) + +!0 = !{} +