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Revert "Transforms: reapply SVN r219899"

This reverts commit r220811 and r220839. It made an incorrect change to
musttail handling.

llvm-svn: 221226
This commit is contained in:
Reid Kleckner 2014-11-04 02:02:14 +00:00
parent 271e57605b
commit 159d4a83e8
7 changed files with 49 additions and 110 deletions

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@ -253,7 +253,12 @@ bool TailCallElim::markTails(Function &F, bool &AllCallsAreTailCalls) {
return false;
AllCallsAreTailCalls = true;
// The local stack holds all alloca instructions and all byval arguments.
AllocaDerivedValueTracker Tracker;
for (Argument &Arg : F.args()) {
if (Arg.hasByValAttr())
Tracker.walk(&Arg);
}
for (auto &BB : F) {
for (auto &I : BB)
if (AllocaInst *AI = dyn_cast<AllocaInst>(&I))
@ -309,8 +314,9 @@ bool TailCallElim::markTails(Function &F, bool &AllCallsAreTailCalls) {
for (auto &Arg : CI->arg_operands()) {
if (isa<Constant>(Arg.getUser()))
continue;
if (isa<Argument>(Arg.getUser()))
continue;
if (Argument *A = dyn_cast<Argument>(Arg.getUser()))
if (!A->hasByValAttr())
continue;
SafeToTail = false;
break;
}

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@ -743,8 +743,7 @@ static void HandleByValArgumentInit(Value *Dst, Value *Src, Module *M,
static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
const Function *CalledFunc,
InlineFunctionInfo &IFI,
unsigned ByValAlignment,
bool &AddedNewAllocas) {
unsigned ByValAlignment) {
PointerType *ArgTy = cast<PointerType>(Arg->getType());
Type *AggTy = ArgTy->getElementType();
@ -786,7 +785,6 @@ static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
// Uses of the argument in the function should use our new alloca
// instead.
AddedNewAllocas = true;
return NewAlloca;
}
@ -960,7 +958,6 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
SmallVector<ReturnInst*, 8> Returns;
ClonedCodeInfo InlinedFunctionInfo;
Function::iterator FirstNewBlock;
bool AddedNewAllocas = false;
{ // Scope to destroy VMap after cloning.
ValueToValueMapTy VMap;
@ -984,8 +981,7 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
// modify the struct.
if (CS.isByValArgument(ArgNo)) {
ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
CalledFunc->getParamAlignment(ArgNo+1),
AddedNewAllocas);
CalledFunc->getParamAlignment(ArgNo+1));
if (ActualArg != *AI)
ByValInit.push_back(std::make_pair(ActualArg, (Value*) *AI));
}
@ -1100,18 +1096,9 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
// f -> musttail g -> tail f ==> f -> tail f
// f -> g -> musttail f ==> f -> f
// f -> g -> tail f ==> f -> f
//
// If an alloca was introduced in the frame due to a byval parameter
// being passed to a subsequent call, tail calls must have the tail
// stripped as they may not access variables in the caller's stack.
// A single alloca ripples through out as the alloca may be aliased by
// bitcasts or may escape and be mutated outside of the function.
CallInst::TailCallKind ChildTCK = CI->getTailCallKind();
ChildTCK = std::min(CallSiteTailKind, ChildTCK);
if (AddedNewAllocas)
CI->setTailCallKind(CallInst::TCK_None);
else
CI->setTailCallKind(ChildTCK);
CI->setTailCallKind(ChildTCK);
InlinedMustTailCalls |= CI->isMustTailCall();
// Calls inlined through a 'nounwind' call site should be marked

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@ -34,7 +34,7 @@ define void @frob(i32* %x) {
; CHECK: %[[VAL:.*]] = load i32* %x
; CHECK: store i32 %[[VAL]], i32* %[[POS]]
; CHECK: {{^ *}}call void @ext(i32* %[[POS]]
; CHECK: {{^ *}}call void @ext(i32* null)
; CHECK: tail call void @ext(i32* null)
; CHECK: ret void
tail call void @qux(i32* byval %x)
ret void

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@ -49,6 +49,42 @@ define void @test_musttail_basic_a(i32* %p) {
ret void
}
; Don't insert lifetime end markers here, the lifetime is trivially over due
; the return.
; CHECK: define void @test_byval_a(
; CHECK: musttail call void @test_byval_c(
; CHECK-NEXT: ret void
declare void @test_byval_c(i32* byval %p)
define internal void @test_byval_b(i32* byval %p) {
musttail call void @test_byval_c(i32* byval %p)
ret void
}
define void @test_byval_a(i32* byval %p) {
musttail call void @test_byval_b(i32* byval %p)
ret void
}
; Don't insert a stack restore, we're about to return.
; CHECK: define void @test_dynalloca_a(
; CHECK: call i8* @llvm.stacksave(
; CHECK: alloca i8, i32 %n
; CHECK: musttail call void @test_dynalloca_c(
; CHECK-NEXT: ret void
declare void @escape(i8* %buf)
declare void @test_dynalloca_c(i32* byval %p, i32 %n)
define internal void @test_dynalloca_b(i32* byval %p, i32 %n) alwaysinline {
%buf = alloca i8, i32 %n ; dynamic alloca
call void @escape(i8* %buf) ; escape it
musttail call void @test_dynalloca_c(i32* byval %p, i32 %n)
ret void
}
define void @test_dynalloca_a(i32* byval %p, i32 %n) {
musttail call void @test_dynalloca_b(i32* byval %p, i32 %n)
ret void
}
; We can't merge the returns.
; CHECK: define void @test_multiret_a(
; CHECK: musttail call void @test_multiret_c(

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@ -1,56 +0,0 @@
; RUN: opt -basicaa -dse -inline -S %s | FileCheck %s
declare void @external(i32* byval)
declare i32 @identity(i32* byval)
; An alloca in the inlinee should not force the tail to be stripped
define void @inlinee_with_alloca() {
%local = alloca i32
store i32 42, i32* %local, align 4
tail call void @external(i32* byval %local)
ret void
}
define void @inliner_without_alloca() {
tail call void @inlinee_with_alloca()
ret void
}
; CHECK-LABEL: inliner_without_alloca
; CHECK-NEXT: %local.i = alloca i32
; CHECK: tail call void @external
; CHECK: ret
; An alloca in the inliner should not force the tail to be stripped
define i32 @inliner_with_alloca() {
%local = alloca i32
store i32 42, i32* %local, align 4
%1 = tail call i32 @identity(i32* byval %local)
ret i32 %1
}
; CHECK-LABEL: inliner_with_alloca
; CHECK: %local = alloca i32
; CHECK: %1 = tail call i32 @identity
; CHECK: ret i32 %1
; Force the synthesis of the value through the byval parameter.
; The alloca should force the tail to be stripped
define void @inlinee_with_passthru(i32* byval %value) {
tail call void @external(i32* byval %value)
ret void
}
define void @strip_tail(i32* %value) {
tail call void @inlinee_with_passthru(i32* %value)
ret void
}
; CHECK-LABEL: strip_tail
; CHECK: %value1 = alloca i32
; CHECK-NOT: tail call void @external
; CHECK: ret void

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@ -147,7 +147,7 @@ cond_false:
; Don't tail call if a byval arg is captured.
define void @test9(i32* byval %a) {
; CHECK-LABEL: define void @test9(
; CHECK: tail call void @use(
; CHECK: {{^ *}}call void @use(
call void @use(i32* %a)
ret void
}

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@ -1,34 +0,0 @@
; RUN: opt -mtriple i386 -Os -S %s -o - | FileCheck %s
; RUN: opt -mtriple x86_64 -Os -S %s -o - | FileCheck %s
; RUN: opt -mtriple armv7 -Os -S %s -o - | FileCheck %s
%struct.D16 = type { [16 x double] }
declare void @_Z2OpP3D16PKS_S2_(%struct.D16*, %struct.D16*, %struct.D16*)
define void @_Z7TestRefRK3D16S1_(%struct.D16* noalias sret %agg.result, %struct.D16* %RHS, %struct.D16* %LHS) {
%1 = alloca %struct.D16*, align 8
%2 = alloca %struct.D16*, align 8
store %struct.D16* %RHS, %struct.D16** %1, align 8
store %struct.D16* %LHS, %struct.D16** %2, align 8
%3 = load %struct.D16** %1, align 8
%4 = load %struct.D16** %2, align 8
call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16* %3, %struct.D16* %4)
ret void
}
; CHECK: define void @_Z7TestRefRK3D16S1_({{.*}}) {
; CHECK: tail call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16* %RHS, %struct.D16* %LHS)
; CHECK: ret void
; CHECK: }
define void @_Z7TestVal3D16S_(%struct.D16* noalias sret %agg.result, %struct.D16* byval align 8 %RHS, %struct.D16* byval align 8 %LHS) {
call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16* %RHS, %struct.D16* %LHS)
ret void
}
; CHECK: define void @_Z7TestVal3D16S_({{.*}}) {
; CHECK: tail call void @_Z2OpP3D16PKS_S2_(%struct.D16* %agg.result, %struct.D16* %RHS, %struct.D16* %LHS)
; CHECK: ret void
; CHECK: }