[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
This revision was automatically updated to reflect the committed changes.
Closed by commit rL341734: Do not use optimized atomic libcalls for misaligned
atomics. (authored by rsmith, committed by ).
Herald added a subscriber: llvm-commits.
Repository:
rL LLVM
https://reviews.llvm.org/D51817
Files:
cfe/trunk/lib/CodeGen/CGAtomic.cpp
cfe/trunk/test/CodeGen/atomic-ops.c
Index: cfe/trunk/test/CodeGen/atomic-ops.c
===
--- cfe/trunk/test/CodeGen/atomic-ops.c
+++ cfe/trunk/test/CodeGen/atomic-ops.c
@@ -198,10 +198,12 @@
struct S fd1(struct S *a) {
// CHECK-LABEL: @fd1
// CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4
- // CHECK: bitcast %struct.S* {{.*}} to i64*
+ // CHECK: [[A:%.*]] = bitcast %struct.S* {{.*}} to i64*
// CHECK: [[CAST:%.*]] = bitcast %struct.S* [[RETVAL]] to i64*
- // CHECK: [[CALL:%.*]] = call i64 @__atomic_load_8(
- // CHECK: store i64 [[CALL]], i64* [[CAST]], align 4
+ // CHECK: [[SRC:%.*]] = bitcast i64* [[A]] to i8*
+ // CHECK: [[DEST:%.*]] = bitcast i64* [[CAST]] to i8*
+ // CHECK: call void @__atomic_load(i32 8, i8* [[SRC]], i8* [[DEST]], i32 5)
+ // CHECK: ret
struct S ret;
__atomic_load(a, &ret, memory_order_seq_cst);
return ret;
@@ -218,8 +220,8 @@
// CHECK-NEXT: [[COERCED_A_TMP:%.*]] = bitcast %struct.S* [[LOAD_A_PTR]] to i64*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: call void @__atomic_store_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: call void @__atomic_store(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]],
// CHECK-NEXT: ret void
__atomic_store(a, b, memory_order_seq_cst);
}
@@ -239,9 +241,9 @@
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call i64 @__atomic_exchange_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
- // CHECK-NEXT: store i64 [[CALL]], i64* [[COERCED_C]], align 4
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: call void @__atomic_exchange(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]], i8* [[CAST_C]],
__atomic_exchange(a, b, c, memory_order_seq_cst);
}
@@ -262,8 +264,8 @@
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast i64* [[COERCED_B_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_C:%.*]] = load i64, i64* [[COERCED_C]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange_8(i8* [[COERCED_A]], i8* [[COERCED_B]], i64 [[LOAD_C]]
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange(i32 8, i8* [[COERCED_A]], i8* [[COERCED_B]], i8* [[CAST_C]],
// CHECK-NEXT: ret i1 [[CALL]]
return __atomic_compare_exchange(a, b, c, 1, 5, 5);
}
@@ -634,4 +636,29 @@
return __atomic_add_fetch(i, value, memory_order_seq_cst);
}
+void test_underaligned() {
+ // CHECK-LABEL: @test_underaligned
+ struct Underaligned { char c[8]; } underaligned_a, underaligned_b, underaligned_c;
+
+ // CHECK: call void @__atomic_load(i32 8,
+ __atomic_load(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_store(i32 8,
+ __atomic_store(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_exchange(i32 8,
+ __atomic_exchange(&underaligned_a, &underaligned_b, &underaligned_c, memory_order_seq_cst);
+ // CHECK: call {{.*}} @__atomic_compare_exchange(i32 8,
+ __atomic_compare_exchange(&underaligned_a, &underaligned_b, &underaligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+
+ __attribute__((aligned)) struct Underaligned aligned_a, aligned_b, aligned_c;
+
+ // CHECK: load atomic
+ __atomic_load(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: store atomic
+ __atomic_store(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: atomicrmw xchg
+ __atomic_exchange(&aligned_a, &aligned_b, &aligned_c, memory_order_seq_cst);
+ // CHECK: cmpxchg weak
+ __atomic_compare_exchange(&aligned_a, &aligned_b, &aligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+}
+
#endif
Index: cfe/trunk/lib/CodeGen/CGAtomic.cpp
===
--- cfe/trunk/lib/CodeGen/CGAtomic.cpp
+++ cfe/trunk/lib/CodeGen/CGAtomic.cpp
[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
This revision was automatically updated to reflect the committed changes.
Closed by commit rC341734: Do not use optimized atomic libcalls for misaligned
atomics. (authored by rsmith, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D51817?vs=164517&id=164544#toc
Repository:
rL LLVM
https://reviews.llvm.org/D51817
Files:
lib/CodeGen/CGAtomic.cpp
test/CodeGen/atomic-ops.c
Index: test/CodeGen/atomic-ops.c
===
--- test/CodeGen/atomic-ops.c
+++ test/CodeGen/atomic-ops.c
@@ -198,10 +198,12 @@
struct S fd1(struct S *a) {
// CHECK-LABEL: @fd1
// CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4
- // CHECK: bitcast %struct.S* {{.*}} to i64*
+ // CHECK: [[A:%.*]] = bitcast %struct.S* {{.*}} to i64*
// CHECK: [[CAST:%.*]] = bitcast %struct.S* [[RETVAL]] to i64*
- // CHECK: [[CALL:%.*]] = call i64 @__atomic_load_8(
- // CHECK: store i64 [[CALL]], i64* [[CAST]], align 4
+ // CHECK: [[SRC:%.*]] = bitcast i64* [[A]] to i8*
+ // CHECK: [[DEST:%.*]] = bitcast i64* [[CAST]] to i8*
+ // CHECK: call void @__atomic_load(i32 8, i8* [[SRC]], i8* [[DEST]], i32 5)
+ // CHECK: ret
struct S ret;
__atomic_load(a, &ret, memory_order_seq_cst);
return ret;
@@ -218,8 +220,8 @@
// CHECK-NEXT: [[COERCED_A_TMP:%.*]] = bitcast %struct.S* [[LOAD_A_PTR]] to i64*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: call void @__atomic_store_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: call void @__atomic_store(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]],
// CHECK-NEXT: ret void
__atomic_store(a, b, memory_order_seq_cst);
}
@@ -239,9 +241,9 @@
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call i64 @__atomic_exchange_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
- // CHECK-NEXT: store i64 [[CALL]], i64* [[COERCED_C]], align 4
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: call void @__atomic_exchange(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]], i8* [[CAST_C]],
__atomic_exchange(a, b, c, memory_order_seq_cst);
}
@@ -262,8 +264,8 @@
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast i64* [[COERCED_B_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_C:%.*]] = load i64, i64* [[COERCED_C]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange_8(i8* [[COERCED_A]], i8* [[COERCED_B]], i64 [[LOAD_C]]
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange(i32 8, i8* [[COERCED_A]], i8* [[COERCED_B]], i8* [[CAST_C]],
// CHECK-NEXT: ret i1 [[CALL]]
return __atomic_compare_exchange(a, b, c, 1, 5, 5);
}
@@ -634,4 +636,29 @@
return __atomic_add_fetch(i, value, memory_order_seq_cst);
}
+void test_underaligned() {
+ // CHECK-LABEL: @test_underaligned
+ struct Underaligned { char c[8]; } underaligned_a, underaligned_b, underaligned_c;
+
+ // CHECK: call void @__atomic_load(i32 8,
+ __atomic_load(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_store(i32 8,
+ __atomic_store(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_exchange(i32 8,
+ __atomic_exchange(&underaligned_a, &underaligned_b, &underaligned_c, memory_order_seq_cst);
+ // CHECK: call {{.*}} @__atomic_compare_exchange(i32 8,
+ __atomic_compare_exchange(&underaligned_a, &underaligned_b, &underaligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+
+ __attribute__((aligned)) struct Underaligned aligned_a, aligned_b, aligned_c;
+
+ // CHECK: load atomic
+ __atomic_load(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: store atomic
+ __atomic_store(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: atomicrmw xchg
+ __atomic_exchange(&aligned_a, &aligned_b, &aligned_c, memory_order_seq_cst);
+ // CHECK: cmpxchg weak
+ __atomic_compare_exchange(&aligned_a, &aligned_b, &aligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+}
+
#endif
Index: lib/CodeGen/CGAtomic.cpp
===
--- lib/CodeGen/CGAtomic.cpp
+++ lib/CodeGen/CGAtomic.cpp
@@ -927,6 +927,15 @@
UseOptim
[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
efriedma accepted this revision. efriedma added a comment. This revision is now accepted and ready to land. LGTM Comment at: lib/CodeGen/CGAtomic.cpp:949 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__atomic_load_n: case AtomicExpr::AO__atomic_store_n: rsmith wrote: > efriedma wrote: > > Is there any particular reason to expect that the pointer operand to > > __atomic_load_n can't be misaligned? I mean, for most ABIs, integers are > > naturally aligned, but that isn't actually a hard rule. > `__atomic_load_n` is, by definition, guaranteed to never call an unoptimized > atomic library function (see https://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary). > [I think the purpose of the `..._n` variants is to provide builtins that > libatomic's unoptimized library functions can use and have a guarantee that > they will not be recursively re-entered.] Oh, okay, makes sense. Repository: rC Clang https://reviews.llvm.org/D51817 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
rsmith added inline comments. Comment at: lib/CodeGen/CGAtomic.cpp:949 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__atomic_load_n: case AtomicExpr::AO__atomic_store_n: efriedma wrote: > Is there any particular reason to expect that the pointer operand to > __atomic_load_n can't be misaligned? I mean, for most ABIs, integers are > naturally aligned, but that isn't actually a hard rule. `__atomic_load_n` is, by definition, guaranteed to never call an unoptimized atomic library function (see https://gcc.gnu.org/wiki/Atomic/GCCMM/LIbrary). [I think the purpose of the `..._n` variants is to provide builtins that libatomic's unoptimized library functions can use and have a guarantee that they will not be recursively re-entered.] Repository: rC Clang https://reviews.llvm.org/D51817 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
efriedma added inline comments. Comment at: lib/CodeGen/CGAtomic.cpp:949 case AtomicExpr::AO__opencl_atomic_compare_exchange_strong: case AtomicExpr::AO__atomic_load_n: case AtomicExpr::AO__atomic_store_n: Is there any particular reason to expect that the pointer operand to __atomic_load_n can't be misaligned? I mean, for most ABIs, integers are naturally aligned, but that isn't actually a hard rule. Repository: rC Clang https://reviews.llvm.org/D51817 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D51817: Do not use optimized atomic libcalls for misaligned atomics.
rsmith created this revision.
rsmith added reviewers: jyknight, t.p.northover.
Herald added a subscriber: jfb.
The optimized (__atomic_foo_) libcalls assume that the atomic object
is properly aligned, so should never be called on an underaligned
object.
This addresses one of several problems identified in PR38846.
Repository:
rC Clang
https://reviews.llvm.org/D51817
Files:
lib/CodeGen/CGAtomic.cpp
test/CodeGen/atomic-ops.c
Index: test/CodeGen/atomic-ops.c
===
--- test/CodeGen/atomic-ops.c
+++ test/CodeGen/atomic-ops.c
@@ -198,10 +198,12 @@
struct S fd1(struct S *a) {
// CHECK-LABEL: @fd1
// CHECK: [[RETVAL:%.*]] = alloca %struct.S, align 4
- // CHECK: bitcast %struct.S* {{.*}} to i64*
+ // CHECK: [[A:%.*]] = bitcast %struct.S* {{.*}} to i64*
// CHECK: [[CAST:%.*]] = bitcast %struct.S* [[RETVAL]] to i64*
- // CHECK: [[CALL:%.*]] = call i64 @__atomic_load_8(
- // CHECK: store i64 [[CALL]], i64* [[CAST]], align 4
+ // CHECK: [[SRC:%.*]] = bitcast i64* [[A]] to i8*
+ // CHECK: [[DEST:%.*]] = bitcast i64* [[CAST]] to i8*
+ // CHECK: call void @__atomic_load(i32 8, i8* [[SRC]], i8* [[DEST]], i32 5)
+ // CHECK: ret
struct S ret;
__atomic_load(a, &ret, memory_order_seq_cst);
return ret;
@@ -218,8 +220,8 @@
// CHECK-NEXT: [[COERCED_A_TMP:%.*]] = bitcast %struct.S* [[LOAD_A_PTR]] to i64*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: call void @__atomic_store_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: call void @__atomic_store(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]],
// CHECK-NEXT: ret void
__atomic_store(a, b, memory_order_seq_cst);
}
@@ -239,9 +241,9 @@
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast %struct.S* [[LOAD_B_PTR]] to i64*
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_B:%.*]] = load i64, i64* [[COERCED_B]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call i64 @__atomic_exchange_8(i8* [[COERCED_A]], i64 [[LOAD_B]],
- // CHECK-NEXT: store i64 [[CALL]], i64* [[COERCED_C]], align 4
+ // CHECK-NEXT: [[CAST_B:%.*]] = bitcast i64* [[COERCED_B]] to i8*
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: call void @__atomic_exchange(i32 8, i8* [[COERCED_A]], i8* [[CAST_B]], i8* [[CAST_C]],
__atomic_exchange(a, b, c, memory_order_seq_cst);
}
@@ -262,8 +264,8 @@
// CHECK-NEXT: [[COERCED_C:%.*]] = bitcast %struct.S* [[LOAD_C_PTR]] to i64*
// CHECK-NEXT: [[COERCED_A:%.*]] = bitcast i64* [[COERCED_A_TMP]] to i8*
// CHECK-NEXT: [[COERCED_B:%.*]] = bitcast i64* [[COERCED_B_TMP]] to i8*
- // CHECK-NEXT: [[LOAD_C:%.*]] = load i64, i64* [[COERCED_C]], align 4
- // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange_8(i8* [[COERCED_A]], i8* [[COERCED_B]], i64 [[LOAD_C]]
+ // CHECK-NEXT: [[CAST_C:%.*]] = bitcast i64* [[COERCED_C]] to i8*
+ // CHECK-NEXT: [[CALL:%.*]] = call zeroext i1 @__atomic_compare_exchange(i32 8, i8* [[COERCED_A]], i8* [[COERCED_B]], i8* [[CAST_C]],
// CHECK-NEXT: ret i1 [[CALL]]
return __atomic_compare_exchange(a, b, c, 1, 5, 5);
}
@@ -634,4 +636,29 @@
return __atomic_add_fetch(i, value, memory_order_seq_cst);
}
+void test_underaligned() {
+ // CHECK-LABEL: @test_underaligned
+ struct Underaligned { char c[8]; } underaligned_a, underaligned_b, underaligned_c;
+
+ // CHECK: call void @__atomic_load(i32 8,
+ __atomic_load(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_store(i32 8,
+ __atomic_store(&underaligned_a, &underaligned_b, memory_order_seq_cst);
+ // CHECK: call void @__atomic_exchange(i32 8,
+ __atomic_exchange(&underaligned_a, &underaligned_b, &underaligned_c, memory_order_seq_cst);
+ // CHECK: call {{.*}} @__atomic_compare_exchange(i32 8,
+ __atomic_compare_exchange(&underaligned_a, &underaligned_b, &underaligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+
+ __attribute__((aligned)) struct Underaligned aligned_a, aligned_b, aligned_c;
+
+ // CHECK: load atomic
+ __atomic_load(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: store atomic
+ __atomic_store(&aligned_a, &aligned_b, memory_order_seq_cst);
+ // CHECK: atomicrmw xchg
+ __atomic_exchange(&aligned_a, &aligned_b, &aligned_c, memory_order_seq_cst);
+ // CHECK: cmpxchg weak
+ __atomic_compare_exchange(&aligned_a, &aligned_b, &aligned_c, 1, memory_order_seq_cst, memory_order_seq_cst);
+}
+
#endif
Index: lib/CodeGen/CGAtomic.cpp
===
--- lib/CodeGen/CGAtomic.cpp
+++ lib/CodeGen/CGAtomic.cpp
