diff --git a/llvm/docs/LangRef.html b/llvm/docs/LangRef.html
index 0ec08eb0a058..7882da67e1aa 100644
--- a/llvm/docs/LangRef.html
+++ b/llvm/docs/LangRef.html
@@ -1262,6 +1262,11 @@ define void @f() optsize { ... }
the ELF x86-64 abi, but it can be disabled for some compilation
units.
+
returns_twice
+ This attribute indicates that this function can return
+ twice. The C setjmp
is an example of such a function.
+ The compiler disables some optimizations (like tail calls) in the caller of
+ these functions.
diff --git a/llvm/include/llvm/Attributes.h b/llvm/include/llvm/Attributes.h
index cd3ee35d7497..2d7b33b29bcf 100644
--- a/llvm/include/llvm/Attributes.h
+++ b/llvm/include/llvm/Attributes.h
@@ -65,8 +65,7 @@ const Attributes StackAlignment = 7<<26; ///< Alignment of stack for
///of alignment with +1 bias
///0 means unaligned (different from
///alignstack(1))
-const Attributes Hotpatch = 1<<29; ///< Function should have special
- ///'hotpatch' sequence in prologue
+const Attributes ReturnsTwice = 1<<29; ///< Function can return twice
const Attributes UWTable = 1<<30; ///< Function must be in a unwind
///table
const Attributes NonLazyBind = 1U<<31; ///< Function is called early and/or
@@ -93,7 +92,7 @@ const Attributes ParameterOnly = ByVal | Nest | StructRet | NoCapture;
const Attributes FunctionOnly = NoReturn | NoUnwind | ReadNone | ReadOnly |
NoInline | AlwaysInline | OptimizeForSize | StackProtect | StackProtectReq |
NoRedZone | NoImplicitFloat | Naked | InlineHint | StackAlignment |
- Hotpatch | UWTable | NonLazyBind;
+ UWTable | NonLazyBind | ReturnsTwice;
/// @brief Parameter attributes that do not apply to vararg call arguments.
const Attributes VarArgsIncompatible = StructRet;
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index fdadd1ba93f6..029f9426f683 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -558,6 +558,7 @@ lltok::Kind LLLexer::LexIdentifier() {
KEYWORD(readnone);
KEYWORD(readonly);
KEYWORD(uwtable);
+ KEYWORD(returns_twice);
KEYWORD(inlinehint);
KEYWORD(noinline);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 4d233cab6fbe..cafaab01afd9 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -911,6 +911,7 @@ bool LLParser::ParseOptionalAttrs(unsigned &Attrs, unsigned AttrKind) {
case lltok::kw_noreturn: Attrs |= Attribute::NoReturn; break;
case lltok::kw_nounwind: Attrs |= Attribute::NoUnwind; break;
case lltok::kw_uwtable: Attrs |= Attribute::UWTable; break;
+ case lltok::kw_returns_twice: Attrs |= Attribute::ReturnsTwice; break;
case lltok::kw_noinline: Attrs |= Attribute::NoInline; break;
case lltok::kw_readnone: Attrs |= Attribute::ReadNone; break;
case lltok::kw_readonly: Attrs |= Attribute::ReadOnly; break;
@@ -922,7 +923,6 @@ bool LLParser::ParseOptionalAttrs(unsigned &Attrs, unsigned AttrKind) {
case lltok::kw_noredzone: Attrs |= Attribute::NoRedZone; break;
case lltok::kw_noimplicitfloat: Attrs |= Attribute::NoImplicitFloat; break;
case lltok::kw_naked: Attrs |= Attribute::Naked; break;
- case lltok::kw_hotpatch: Attrs |= Attribute::Hotpatch; break;
case lltok::kw_nonlazybind: Attrs |= Attribute::NonLazyBind; break;
case lltok::kw_alignstack: {
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index d22ecf31bdae..acdd4b8ebf83 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -90,6 +90,7 @@ namespace lltok {
kw_readnone,
kw_readonly,
kw_uwtable,
+ kw_returns_twice,
kw_inlinehint,
kw_noinline,
diff --git a/llvm/lib/Target/CppBackend/CPPBackend.cpp b/llvm/lib/Target/CppBackend/CPPBackend.cpp
index 16401a8f98b9..9a6ff3292ab6 100644
--- a/llvm/lib/Target/CppBackend/CPPBackend.cpp
+++ b/llvm/lib/Target/CppBackend/CPPBackend.cpp
@@ -470,7 +470,7 @@ void CppWriter::printAttributes(const AttrListPtr &PAL,
HANDLE_ATTR(NoImplicitFloat);
HANDLE_ATTR(Naked);
HANDLE_ATTR(InlineHint);
- HANDLE_ATTR(Hotpatch);
+ HANDLE_ATTR(ReturnsTwice);
HANDLE_ATTR(UWTable);
HANDLE_ATTR(NonLazyBind);
#undef HANDLE_ATTR
diff --git a/llvm/lib/VMCore/Attributes.cpp b/llvm/lib/VMCore/Attributes.cpp
index b728b9284b44..485be75d1b12 100644
--- a/llvm/lib/VMCore/Attributes.cpp
+++ b/llvm/lib/VMCore/Attributes.cpp
@@ -38,6 +38,8 @@ std::string Attribute::getAsString(Attributes Attrs) {
Result += "nounwind ";
if (Attrs & Attribute::UWTable)
Result += "uwtable ";
+ if (Attrs & Attribute::ReturnsTwice)
+ Result += "returns_twice ";
if (Attrs & Attribute::InReg)
Result += "inreg ";
if (Attrs & Attribute::NoAlias)
@@ -72,8 +74,6 @@ std::string Attribute::getAsString(Attributes Attrs) {
Result += "noimplicitfloat ";
if (Attrs & Attribute::Naked)
Result += "naked ";
- if (Attrs & Attribute::Hotpatch)
- Result += "hotpatch ";
if (Attrs & Attribute::NonLazyBind)
Result += "nonlazybind ";
if (Attrs & Attribute::StackAlignment) {
diff --git a/llvm/test/Transforms/Mem2Reg/2007-08-27-VolatileLoadsStores.ll b/llvm/test/Transforms/Mem2Reg/2007-08-27-VolatileLoadsStores.ll
index 50683cf8baa0..52a837531296 100644
--- a/llvm/test/Transforms/Mem2Reg/2007-08-27-VolatileLoadsStores.ll
+++ b/llvm/test/Transforms/Mem2Reg/2007-08-27-VolatileLoadsStores.ll
@@ -42,6 +42,6 @@ return: ; preds = %bb6
ret i32 %retval8
}
-declare i32 @_setjmp(%struct.__jmp_buf_tag*)
+declare i32 @_setjmp(%struct.__jmp_buf_tag*) returns_twice
declare void @g()
diff --git a/llvm/test/Transforms/TailCallElim/setjmp.ll b/llvm/test/Transforms/TailCallElim/setjmp.ll
index 7b7fe568259e..35bb75dddb30 100644
--- a/llvm/test/Transforms/TailCallElim/setjmp.ll
+++ b/llvm/test/Transforms/TailCallElim/setjmp.ll
@@ -11,6 +11,6 @@ bb:
ret void
}
-declare i32 @setjmp(i32*)
+declare i32 @setjmp(i32*) returns_twice
declare void @bar()