Hi rsmith,
Prior to GCC 4.4, __sync_fetch_and_nand was implemented as:
{ tmp = *ptr; *ptr = ~tmp & value; return tmp; }
but this was changed in GCC 4.4 to be:
{ tmp = *ptr; *ptr = ~(tmp & value); return tmp; }
in response to this change, support for __sync_fetch_and_nand (and
__sync_nand_and_fetch) was removed in r99522 in order to avoid miscompiling
code depending on the old semantics. However, at this point:
1. Many years have passed, and the amount of code relying on the old semantics
is likely smaller
2. Through the work of many contributors, all LLVM backends have been updated
such that "atomicrmw nand" provides the newer GCC 4.4+ semantics (this process
was complete July of 2014 (added to the release notes in r212635).
3. The lack of this intrinsic is now a needless impediment to porting codes
from GCC to Clang (I've now seen several examples of this).
It is true, however, that we still set __GNUC_MINOR__ to 2 (corresponding to
GCC 4.2). To compensate for this, and to address the original concern regarding
code relying on the old semantics, I've added a warning in this patch that
specifically details the fact that the semantics have changed and that we
provide the newer semantics.
Fixes PR8842.
Please review and thanks again!
http://reviews.llvm.org/D5429
Files:
include/clang/Basic/Builtins.def
include/clang/Basic/DiagnosticSemaKinds.td
lib/CodeGen/CGBuiltin.cpp
lib/Sema/SemaChecking.cpp
test/CodeGen/Atomics.c
test/CodeGen/atomic.c
test/Sema/builtins.c
Index: include/clang/Basic/Builtins.def
===================================================================
--- include/clang/Basic/Builtins.def
+++ include/clang/Basic/Builtins.def
@@ -541,6 +541,12 @@
BUILTIN(__sync_fetch_and_xor_8, "LLiLLiD*LLi.", "tn")
BUILTIN(__sync_fetch_and_xor_16, "LLLiLLLiD*LLLi.", "tn")
+BUILTIN(__sync_fetch_and_nand, "v.", "t")
+BUILTIN(__sync_fetch_and_nand_1, "ccD*c.", "tn")
+BUILTIN(__sync_fetch_and_nand_2, "ssD*s.", "tn")
+BUILTIN(__sync_fetch_and_nand_4, "iiD*i.", "tn")
+BUILTIN(__sync_fetch_and_nand_8, "LLiLLiD*LLi.", "tn")
+BUILTIN(__sync_fetch_and_nand_16, "LLLiLLLiD*LLLi.", "tn")
BUILTIN(__sync_add_and_fetch, "v.", "t")
BUILTIN(__sync_add_and_fetch_1, "ccD*c.", "tn")
@@ -577,6 +583,13 @@
BUILTIN(__sync_xor_and_fetch_8, "LLiLLiD*LLi.", "tn")
BUILTIN(__sync_xor_and_fetch_16, "LLLiLLLiD*LLLi.", "tn")
+BUILTIN(__sync_nand_and_fetch, "v.", "t")
+BUILTIN(__sync_nand_and_fetch_1, "ccD*c.", "tn")
+BUILTIN(__sync_nand_and_fetch_2, "ssD*s.", "tn")
+BUILTIN(__sync_nand_and_fetch_4, "iiD*i.", "tn")
+BUILTIN(__sync_nand_and_fetch_8, "LLiLLiD*LLi.", "tn")
+BUILTIN(__sync_nand_and_fetch_16, "LLLiLLLiD*LLLi.", "tn")
+
BUILTIN(__sync_bool_compare_and_swap, "v.", "t")
BUILTIN(__sync_bool_compare_and_swap_1, "bcD*cc.", "tn")
BUILTIN(__sync_bool_compare_and_swap_2, "bsD*ss.", "tn")
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -6875,6 +6875,11 @@
"attribute %0 is already applied with different parameters">,
InGroup<IgnoredAttributes>;
+def warn_gcc44_semantics_change : Warning<
+ "the semantics of this intrinsic changed with GCC version 4.4 - "
+ "the newer semantics are provided here">,
+ InGroup<DiagGroup<"gcc-intrinsic-semantics-changed">>;
+
// Type
def ext_invalid_sign_spec : Extension<"'%0' cannot be signed or unsigned">;
def warn_receiver_forward_class : Warning<
Index: lib/CodeGen/CGBuiltin.cpp
===================================================================
--- lib/CodeGen/CGBuiltin.cpp
+++ lib/CodeGen/CGBuiltin.cpp
@@ -113,7 +113,8 @@
static RValue EmitBinaryAtomicPost(CodeGenFunction &CGF,
llvm::AtomicRMWInst::BinOp Kind,
const CallExpr *E,
- Instruction::BinaryOps Op) {
+ Instruction::BinaryOps Op,
+ bool Invert = false) {
QualType T = E->getType();
assert(E->getArg(0)->getType()->isPointerType());
assert(CGF.getContext().hasSameUnqualifiedType(T,
@@ -138,6 +139,9 @@
CGF.Builder.CreateAtomicRMW(Kind, Args[0], Args[1],
llvm::SequentiallyConsistent);
Result = CGF.Builder.CreateBinOp(Op, Result, Args[1]);
+ if (Invert)
+ Result = CGF.Builder.CreateBinOp(llvm::Instruction::Xor, Result,
+ llvm::ConstantInt::get(IntType, -1));
Result = EmitFromInt(CGF, Result, T, ValueType);
return RValue::get(Result);
}
@@ -871,11 +875,13 @@
case Builtin::BI__sync_fetch_and_or:
case Builtin::BI__sync_fetch_and_and:
case Builtin::BI__sync_fetch_and_xor:
+ case Builtin::BI__sync_fetch_and_nand:
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_xor_and_fetch:
+ case Builtin::BI__sync_nand_and_fetch:
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_bool_compare_and_swap:
case Builtin::BI__sync_lock_test_and_set:
@@ -912,6 +918,12 @@
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
return EmitBinaryAtomic(*this, llvm::AtomicRMWInst::Xor, E);
+ case Builtin::BI__sync_fetch_and_nand_1:
+ case Builtin::BI__sync_fetch_and_nand_2:
+ case Builtin::BI__sync_fetch_and_nand_4:
+ case Builtin::BI__sync_fetch_and_nand_8:
+ case Builtin::BI__sync_fetch_and_nand_16:
+ return EmitBinaryAtomic(*this, llvm::AtomicRMWInst::Nand, E);
// Clang extensions: not overloaded yet.
case Builtin::BI__sync_fetch_and_min:
@@ -958,6 +970,13 @@
case Builtin::BI__sync_xor_and_fetch_16:
return EmitBinaryAtomicPost(*this, llvm::AtomicRMWInst::Xor, E,
llvm::Instruction::Xor);
+ case Builtin::BI__sync_nand_and_fetch_1:
+ case Builtin::BI__sync_nand_and_fetch_2:
+ case Builtin::BI__sync_nand_and_fetch_4:
+ case Builtin::BI__sync_nand_and_fetch_8:
+ case Builtin::BI__sync_nand_and_fetch_16:
+ return EmitBinaryAtomicPost(*this, llvm::AtomicRMWInst::Nand, E,
+ llvm::Instruction::And, true);
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -273,6 +273,12 @@
case Builtin::BI__sync_fetch_and_xor_4:
case Builtin::BI__sync_fetch_and_xor_8:
case Builtin::BI__sync_fetch_and_xor_16:
+ case Builtin::BI__sync_fetch_and_nand:
+ case Builtin::BI__sync_fetch_and_nand_1:
+ case Builtin::BI__sync_fetch_and_nand_2:
+ case Builtin::BI__sync_fetch_and_nand_4:
+ case Builtin::BI__sync_fetch_and_nand_8:
+ case Builtin::BI__sync_fetch_and_nand_16:
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
@@ -303,6 +309,12 @@
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
+ case Builtin::BI__sync_nand_and_fetch:
+ case Builtin::BI__sync_nand_and_fetch_1:
+ case Builtin::BI__sync_nand_and_fetch_2:
+ case Builtin::BI__sync_nand_and_fetch_4:
+ case Builtin::BI__sync_nand_and_fetch_8:
+ case Builtin::BI__sync_nand_and_fetch_16:
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
@@ -1516,12 +1528,14 @@
BUILTIN_ROW(__sync_fetch_and_or),
BUILTIN_ROW(__sync_fetch_and_and),
BUILTIN_ROW(__sync_fetch_and_xor),
+ BUILTIN_ROW(__sync_fetch_and_nand),
BUILTIN_ROW(__sync_add_and_fetch),
BUILTIN_ROW(__sync_sub_and_fetch),
BUILTIN_ROW(__sync_and_and_fetch),
BUILTIN_ROW(__sync_or_and_fetch),
BUILTIN_ROW(__sync_xor_and_fetch),
+ BUILTIN_ROW(__sync_nand_and_fetch),
BUILTIN_ROW(__sync_val_compare_and_swap),
BUILTIN_ROW(__sync_bool_compare_and_swap),
@@ -1551,6 +1565,7 @@
// as the number of fixed args.
unsigned BuiltinID = FDecl->getBuiltinID();
unsigned BuiltinIndex, NumFixed = 1;
+ bool WarnAboutSemanticsChange = false;
switch (BuiltinID) {
default: llvm_unreachable("Unknown overloaded atomic builtin!");
case Builtin::BI__sync_fetch_and_add:
@@ -1598,58 +1613,78 @@
BuiltinIndex = 4;
break;
+ case Builtin::BI__sync_fetch_and_nand:
+ case Builtin::BI__sync_fetch_and_nand_1:
+ case Builtin::BI__sync_fetch_and_nand_2:
+ case Builtin::BI__sync_fetch_and_nand_4:
+ case Builtin::BI__sync_fetch_and_nand_8:
+ case Builtin::BI__sync_fetch_and_nand_16:
+ BuiltinIndex = 5;
+ WarnAboutSemanticsChange = true;
+ break;
+
case Builtin::BI__sync_add_and_fetch:
case Builtin::BI__sync_add_and_fetch_1:
case Builtin::BI__sync_add_and_fetch_2:
case Builtin::BI__sync_add_and_fetch_4:
case Builtin::BI__sync_add_and_fetch_8:
case Builtin::BI__sync_add_and_fetch_16:
- BuiltinIndex = 5;
+ BuiltinIndex = 6;
break;
case Builtin::BI__sync_sub_and_fetch:
case Builtin::BI__sync_sub_and_fetch_1:
case Builtin::BI__sync_sub_and_fetch_2:
case Builtin::BI__sync_sub_and_fetch_4:
case Builtin::BI__sync_sub_and_fetch_8:
case Builtin::BI__sync_sub_and_fetch_16:
- BuiltinIndex = 6;
+ BuiltinIndex = 7;
break;
case Builtin::BI__sync_and_and_fetch:
case Builtin::BI__sync_and_and_fetch_1:
case Builtin::BI__sync_and_and_fetch_2:
case Builtin::BI__sync_and_and_fetch_4:
case Builtin::BI__sync_and_and_fetch_8:
case Builtin::BI__sync_and_and_fetch_16:
- BuiltinIndex = 7;
+ BuiltinIndex = 8;
break;
case Builtin::BI__sync_or_and_fetch:
case Builtin::BI__sync_or_and_fetch_1:
case Builtin::BI__sync_or_and_fetch_2:
case Builtin::BI__sync_or_and_fetch_4:
case Builtin::BI__sync_or_and_fetch_8:
case Builtin::BI__sync_or_and_fetch_16:
- BuiltinIndex = 8;
+ BuiltinIndex = 9;
break;
case Builtin::BI__sync_xor_and_fetch:
case Builtin::BI__sync_xor_and_fetch_1:
case Builtin::BI__sync_xor_and_fetch_2:
case Builtin::BI__sync_xor_and_fetch_4:
case Builtin::BI__sync_xor_and_fetch_8:
case Builtin::BI__sync_xor_and_fetch_16:
- BuiltinIndex = 9;
+ BuiltinIndex = 10;
+ break;
+
+ case Builtin::BI__sync_nand_and_fetch:
+ case Builtin::BI__sync_nand_and_fetch_1:
+ case Builtin::BI__sync_nand_and_fetch_2:
+ case Builtin::BI__sync_nand_and_fetch_4:
+ case Builtin::BI__sync_nand_and_fetch_8:
+ case Builtin::BI__sync_nand_and_fetch_16:
+ BuiltinIndex = 11;
+ WarnAboutSemanticsChange = true;
break;
case Builtin::BI__sync_val_compare_and_swap:
case Builtin::BI__sync_val_compare_and_swap_1:
case Builtin::BI__sync_val_compare_and_swap_2:
case Builtin::BI__sync_val_compare_and_swap_4:
case Builtin::BI__sync_val_compare_and_swap_8:
case Builtin::BI__sync_val_compare_and_swap_16:
- BuiltinIndex = 10;
+ BuiltinIndex = 12;
NumFixed = 2;
break;
@@ -1659,7 +1694,7 @@
case Builtin::BI__sync_bool_compare_and_swap_4:
case Builtin::BI__sync_bool_compare_and_swap_8:
case Builtin::BI__sync_bool_compare_and_swap_16:
- BuiltinIndex = 11;
+ BuiltinIndex = 13;
NumFixed = 2;
ResultType = Context.BoolTy;
break;
@@ -1670,16 +1705,16 @@
case Builtin::BI__sync_lock_test_and_set_4:
case Builtin::BI__sync_lock_test_and_set_8:
case Builtin::BI__sync_lock_test_and_set_16:
- BuiltinIndex = 12;
+ BuiltinIndex = 14;
break;
case Builtin::BI__sync_lock_release:
case Builtin::BI__sync_lock_release_1:
case Builtin::BI__sync_lock_release_2:
case Builtin::BI__sync_lock_release_4:
case Builtin::BI__sync_lock_release_8:
case Builtin::BI__sync_lock_release_16:
- BuiltinIndex = 13;
+ BuiltinIndex = 15;
NumFixed = 0;
ResultType = Context.VoidTy;
break;
@@ -1690,7 +1725,7 @@
case Builtin::BI__sync_swap_4:
case Builtin::BI__sync_swap_8:
case Builtin::BI__sync_swap_16:
- BuiltinIndex = 14;
+ BuiltinIndex = 16;
break;
}
@@ -1703,6 +1738,11 @@
return ExprError();
}
+ if (WarnAboutSemanticsChange) {
+ Diag(TheCall->getLocEnd(), diag::warn_gcc44_semantics_change)
+ << TheCall->getCallee()->getSourceRange();
+ }
+
// Get the decl for the concrete builtin from this, we can tell what the
// concrete integer type we should convert to is.
unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex];
Index: test/CodeGen/Atomics.c
===================================================================
--- test/CodeGen/Atomics.c
+++ test/CodeGen/Atomics.c
@@ -49,6 +49,15 @@
(void) __sync_fetch_and_xor (&sll, 1); // CHECK: atomicrmw xor i64
(void) __sync_fetch_and_xor (&ull, 1); // CHECK: atomicrmw xor i64
+ (void) __sync_fetch_and_nand (&sc, 1); // CHECK: atomicrmw nand i8
+ (void) __sync_fetch_and_nand (&uc, 1); // CHECK: atomicrmw nand i8
+ (void) __sync_fetch_and_nand (&ss, 1); // CHECK: atomicrmw nand i16
+ (void) __sync_fetch_and_nand (&us, 1); // CHECK: atomicrmw nand i16
+ (void) __sync_fetch_and_nand (&si, 1); // CHECK: atomicrmw nand i32
+ (void) __sync_fetch_and_nand (&ui, 1); // CHECK: atomicrmw nand i32
+ (void) __sync_fetch_and_nand (&sll, 1); // CHECK: atomicrmw nand i64
+ (void) __sync_fetch_and_nand (&ull, 1); // CHECK: atomicrmw nand i64
+
(void) __sync_fetch_and_and (&sc, 1); // CHECK: atomicrmw and i8
(void) __sync_fetch_and_and (&uc, 1); // CHECK: atomicrmw and i8
(void) __sync_fetch_and_and (&ss, 1); // CHECK: atomicrmw and i16
@@ -98,6 +107,15 @@
sll = __sync_fetch_and_xor (&sll, 11); // CHECK: atomicrmw xor
ull = __sync_fetch_and_xor (&ull, 11); // CHECK: atomicrmw xor
+ sc = __sync_fetch_and_nand (&sc, 11); // CHECK: atomicrmw nand
+ uc = __sync_fetch_and_nand (&uc, 11); // CHECK: atomicrmw nand
+ ss = __sync_fetch_and_nand (&ss, 11); // CHECK: atomicrmw nand
+ us = __sync_fetch_and_nand (&us, 11); // CHECK: atomicrmw nand
+ si = __sync_fetch_and_nand (&si, 11); // CHECK: atomicrmw nand
+ ui = __sync_fetch_and_nand (&ui, 11); // CHECK: atomicrmw nand
+ sll = __sync_fetch_and_nand (&sll, 11); // CHECK: atomicrmw nand
+ ull = __sync_fetch_and_nand (&ull, 11); // CHECK: atomicrmw nand
+
sc = __sync_fetch_and_and (&sc, 11); // CHECK: atomicrmw and
uc = __sync_fetch_and_and (&uc, 11); // CHECK: atomicrmw and
ss = __sync_fetch_and_and (&ss, 11); // CHECK: atomicrmw and
@@ -147,6 +165,23 @@
sll = __sync_xor_and_fetch (&sll, uc); // CHECK: atomicrmw xor
ull = __sync_xor_and_fetch (&ull, uc); // CHECK: atomicrmw xor
+ sc = __sync_nand_and_fetch (&sc, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ uc = __sync_nand_and_fetch (&uc, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ ss = __sync_nand_and_fetch (&ss, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ us = __sync_nand_and_fetch (&us, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ si = __sync_nand_and_fetch (&si, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ ui = __sync_nand_and_fetch (&ui, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ sll = __sync_nand_and_fetch (&sll, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+ ull = __sync_nand_and_fetch (&ull, uc); // CHECK: atomicrmw nand
+ // CHECK: xor
+
sc = __sync_and_and_fetch (&sc, uc); // CHECK: atomicrmw and
uc = __sync_and_and_fetch (&uc, uc); // CHECK: atomicrmw and
ss = __sync_and_and_fetch (&ss, uc); // CHECK: atomicrmw and
Index: test/CodeGen/atomic.c
===================================================================
--- test/CodeGen/atomic.c
+++ test/CodeGen/atomic.c
@@ -50,7 +50,10 @@
old = __sync_fetch_and_xor(&val, 0xb);
// CHECK: atomicrmw xor i32* %val, i32 11 seq_cst
-
+
+ old = __sync_fetch_and_nand(&val, 0xc);
+ // CHECK: atomicrmw nand i32* %val, i32 12 seq_cst
+
old = __sync_add_and_fetch(&val, 1);
// CHECK: atomicrmw add i32* %val, i32 1 seq_cst
@@ -65,7 +68,10 @@
old = __sync_xor_and_fetch(&valc, 5);
// CHECK: atomicrmw xor i8* %valc, i8 5 seq_cst
-
+
+ old = __sync_nand_and_fetch(&valc, 6);
+ // CHECK: atomicrmw nand i8* %valc, i8 6 seq_cst
+
__sync_val_compare_and_swap((void **)0, (void *)0, (void *)0);
// CHECK: [[PAIR:%[a-z0-9_.]+]] = cmpxchg i32* null, i32 0, i32 0 seq_cst
// CHECK: extractvalue { i32, i1 } [[PAIR]], 0
Index: test/Sema/builtins.c
===================================================================
--- test/Sema/builtins.c
+++ test/Sema/builtins.c
@@ -66,6 +66,11 @@
__sync_fetch_and_add_4(ptr, val);
}
+void test9_4(volatile int* ptr, int val) {
+ // expected-warning@+1 {{the semantics of this intrinsic changed with GCC version 4.4 - the newer semantics are provided here}}
+ __sync_fetch_and_nand(ptr, val);
+}
+
// rdar://7236819
void test10(void) __attribute__((noreturn));
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