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-rw-r--r--llvm/docs/LangRef.rst6
-rw-r--r--llvm/include/llvm/IR/Instructions.h9
-rw-r--r--llvm/lib/AsmParser/LLLexer.cpp1
-rw-r--r--llvm/lib/AsmParser/LLParser.cpp1
-rw-r--r--llvm/lib/AsmParser/LLToken.h1
-rw-r--r--llvm/lib/Bitcode/Reader/BitcodeReader.cpp2
-rw-r--r--llvm/lib/Bitcode/Writer/BitcodeWriter.cpp3
-rw-r--r--llvm/lib/IR/AsmWriter.cpp2
-rw-r--r--llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp6
-rw-r--r--llvm/test/Bitcode/compatibility.ll7
-rw-r--r--llvm/test/Transforms/TailCallElim/notail.ll24
11 files changed, 56 insertions, 6 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
index d2bba5c8a74..d58b7b2e4df 100644
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -8386,7 +8386,7 @@ Syntax:
::
- <result> = [tail | musttail] call [cconv] [ret attrs] <ty> [<fnty>*] <fnptrval>(<function args>) [fn attrs]
+ <result> = [tail | musttail | notail ] call [cconv] [ret attrs] <ty> [<fnty>*] <fnptrval>(<function args>) [fn attrs]
[ operand bundles ]
Overview:
@@ -8439,6 +8439,10 @@ This instruction requires several arguments:
- `Platform-specific constraints are
met. <CodeGenerator.html#tailcallopt>`_
+#. The optional ``notail`` marker indicates that the optimizers should not add
+ ``tail`` or ``musttail`` markers to the call. It is used to prevent tail
+ call optimization from being performed on the call.
+
#. The optional "cconv" marker indicates which :ref:`calling
convention <callingconv>` the call should use. If none is
specified, the call defaults to using C calling conventions. The
diff --git a/llvm/include/llvm/IR/Instructions.h b/llvm/include/llvm/IR/Instructions.h
index c2ade1994f5..263d0918d84 100644
--- a/llvm/include/llvm/IR/Instructions.h
+++ b/llvm/include/llvm/IR/Instructions.h
@@ -1489,16 +1489,21 @@ public:
}
// Note that 'musttail' implies 'tail'.
- enum TailCallKind { TCK_None = 0, TCK_Tail = 1, TCK_MustTail = 2 };
+ enum TailCallKind { TCK_None = 0, TCK_Tail = 1, TCK_MustTail = 2,
+ TCK_NoTail = 3 };
TailCallKind getTailCallKind() const {
return TailCallKind(getSubclassDataFromInstruction() & 3);
}
bool isTailCall() const {
- return (getSubclassDataFromInstruction() & 3) != TCK_None;
+ unsigned Kind = getSubclassDataFromInstruction() & 3;
+ return Kind == TCK_Tail || Kind == TCK_MustTail;
}
bool isMustTailCall() const {
return (getSubclassDataFromInstruction() & 3) == TCK_MustTail;
}
+ bool isNoTailCall() const {
+ return (getSubclassDataFromInstruction() & 3) == TCK_NoTail;
+ }
void setTailCall(bool isTC = true) {
setInstructionSubclassData((getSubclassDataFromInstruction() & ~3) |
unsigned(isTC ? TCK_Tail : TCK_None));
diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index 82d6eb7788c..91ce1fd7669 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -527,6 +527,7 @@ lltok::Kind LLLexer::LexIdentifier() {
KEYWORD(caller);
KEYWORD(tail);
KEYWORD(musttail);
+ KEYWORD(notail);
KEYWORD(target);
KEYWORD(triple);
KEYWORD(unwind);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index 7feb99d555c..aabd9716118 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -4830,6 +4830,7 @@ int LLParser::ParseInstruction(Instruction *&Inst, BasicBlock *BB,
case lltok::kw_call: return ParseCall(Inst, PFS, CallInst::TCK_None);
case lltok::kw_tail: return ParseCall(Inst, PFS, CallInst::TCK_Tail);
case lltok::kw_musttail: return ParseCall(Inst, PFS, CallInst::TCK_MustTail);
+ case lltok::kw_notail: return ParseCall(Inst, PFS, CallInst::TCK_NoTail);
// Memory.
case lltok::kw_alloca: return ParseAlloc(Inst, PFS);
case lltok::kw_load: return ParseLoad(Inst, PFS);
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index ecd6481e6fa..6980790c098 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -54,6 +54,7 @@ namespace lltok {
kw_caller,
kw_tail,
kw_musttail,
+ kw_notail,
kw_target,
kw_triple,
kw_unwind,
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index bc846192fcf..a0029b26ff9 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -5002,6 +5002,8 @@ std::error_code BitcodeReader::parseFunctionBody(Function *F) {
TCK = CallInst::TCK_Tail;
if (CCInfo & (1 << 14))
TCK = CallInst::TCK_MustTail;
+ if (CCInfo & (1 << 16))
+ TCK = CallInst::TCK_NoTail;
cast<CallInst>(I)->setTailCallKind(TCK);
cast<CallInst>(I)->setAttributes(PAL);
break;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 941e54765f5..b88e55c92cb 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -2131,7 +2131,8 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
Vals.push_back(VE.getAttributeID(CI.getAttributes()));
Vals.push_back((CI.getCallingConv() << 1) | unsigned(CI.isTailCall()) |
- unsigned(CI.isMustTailCall()) << 14 | 1 << 15);
+ unsigned(CI.isMustTailCall()) << 14 | 1 << 15 |
+ unsigned(CI.isNoTailCall()) << 16);
Vals.push_back(VE.getTypeID(FTy));
PushValueAndType(CI.getCalledValue(), InstID, Vals, VE); // Callee
diff --git a/llvm/lib/IR/AsmWriter.cpp b/llvm/lib/IR/AsmWriter.cpp
index db757508594..2f8a3406a37 100644
--- a/llvm/lib/IR/AsmWriter.cpp
+++ b/llvm/lib/IR/AsmWriter.cpp
@@ -2768,6 +2768,8 @@ void AssemblyWriter::printInstruction(const Instruction &I) {
Out << "musttail ";
else if (CI->isTailCall())
Out << "tail ";
+ else if (CI->isNoTailCall())
+ Out << "notail ";
}
// Print out the opcode...
diff --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 1eddef7ef94..7e1ba2c3c90 100644
--- a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -304,7 +304,9 @@ bool TailCallElim::markTails(Function &F, bool &AllCallsAreTailCalls) {
if (!CI || CI->isTailCall())
continue;
- if (CI->doesNotAccessMemory()) {
+ bool IsNoTail = CI->isNoTailCall();
+
+ if (!IsNoTail && CI->doesNotAccessMemory()) {
// A call to a readnone function whose arguments are all things computed
// outside this function can be marked tail. Even if you stored the
// alloca address into a global, a readnone function can't load the
@@ -332,7 +334,7 @@ bool TailCallElim::markTails(Function &F, bool &AllCallsAreTailCalls) {
}
}
- if (Escaped == UNESCAPED && !Tracker.AllocaUsers.count(CI)) {
+ if (!IsNoTail && Escaped == UNESCAPED && !Tracker.AllocaUsers.count(CI)) {
DeferredTails.push_back(CI);
} else {
AllCallsAreTailCalls = false;
diff --git a/llvm/test/Bitcode/compatibility.ll b/llvm/test/Bitcode/compatibility.ll
index 73c24f0370a..49689a99237 100644
--- a/llvm/test/Bitcode/compatibility.ll
+++ b/llvm/test/Bitcode/compatibility.ll
@@ -1144,6 +1144,13 @@ define void @instructions.call_musttail(i8* inalloca %val) {
ret void
}
+define void @instructions.call_notail() {
+ notail call void @f1()
+ ; CHECK: notail call void @f1()
+
+ ret void
+}
+
define void @instructions.landingpad() personality i32 -2 {
invoke void @llvm.donothing() to label %proceed unwind label %catch1
invoke void @llvm.donothing() to label %proceed unwind label %catch2
diff --git a/llvm/test/Transforms/TailCallElim/notail.ll b/llvm/test/Transforms/TailCallElim/notail.ll
new file mode 100644
index 00000000000..e6fdbd1ec77
--- /dev/null
+++ b/llvm/test/Transforms/TailCallElim/notail.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -tailcallelim -S | FileCheck %s
+
+; CHECK: tail call void @callee0()
+; CHECK: notail call void @callee1()
+
+define void @foo1(i32 %a) {
+entry:
+ %tobool = icmp eq i32 %a, 0
+ br i1 %tobool, label %if.else, label %if.then
+
+if.then:
+ call void @callee0()
+ br label %if.end
+
+if.else:
+ notail call void @callee1()
+ br label %if.end
+
+if.end:
+ ret void
+}
+
+declare void @callee0()
+declare void @callee1()
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