[llvm] r252871 - Revert "Revert "[FunctionAttrs] Identify norecurse functions""
James Molloy via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 12 02:55:20 PST 2015
Author: jamesm
Date: Thu Nov 12 04:55:20 2015
New Revision: 252871
URL: http://llvm.org/viewvc/llvm-project?rev=252871&view=rev
Log:
Revert "Revert "[FunctionAttrs] Identify norecurse functions""
This reapplies this patch, with test fixes.
Added:
llvm/trunk/test/Transforms/FunctionAttrs/norecurse.ll
Modified:
llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
llvm/trunk/test/Transforms/FunctionAttrs/2008-09-03-ReadNone.ll
llvm/trunk/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll
llvm/trunk/test/Transforms/FunctionAttrs/atomic.ll
llvm/trunk/test/Transforms/FunctionAttrs/optnone.ll
Modified: llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionAttrs.cpp Thu Nov 12 04:55:20 2015
@@ -50,6 +50,7 @@ STATISTIC(NumReadOnlyArg, "Number of arg
STATISTIC(NumNoAlias, "Number of function returns marked noalias");
STATISTIC(NumNonNullReturn, "Number of function returns marked nonnull");
STATISTIC(NumAnnotated, "Number of attributes added to library functions");
+STATISTIC(NumNoRecurse, "Number of functions marked as norecurse");
namespace {
typedef SmallSetVector<Function *, 8> SCCNodeSet;
@@ -63,7 +64,12 @@ struct FunctionAttrs : public CallGraphS
}
bool runOnSCC(CallGraphSCC &SCC) override;
-
+ bool doInitialization(CallGraph &CG) override {
+ Revisit.clear();
+ return false;
+ }
+ bool doFinalization(CallGraph &CG) override;
+
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
AU.addRequired<AssumptionCacheTracker>();
@@ -73,6 +79,7 @@ struct FunctionAttrs : public CallGraphS
private:
TargetLibraryInfo *TLI;
+ SmallVector<WeakVH,16> Revisit;
};
}
@@ -976,6 +983,14 @@ static void setDoesNotAlias(Function &F,
}
}
+static bool setDoesNotRecurse(Function &F) {
+ if (F.doesNotRecurse())
+ return false;
+ F.setDoesNotRecurse();
+ ++NumNoRecurse;
+ return true;
+}
+
/// Analyze the name and prototype of the given function and set any applicable
/// attributes.
///
@@ -1779,6 +1794,55 @@ static bool inferPrototypeAttributes(Fun
return true;
}
+static bool addNoRecurseAttrs(const CallGraphSCC &SCC,
+ SmallVectorImpl<WeakVH> &Revisit) {
+ // Try and identify functions that do not recurse.
+
+ // If the SCC contains multiple nodes we know for sure there is recursion.
+ if (!SCC.isSingular())
+ return false;
+
+ const CallGraphNode *CGN = *SCC.begin();
+ Function *F = CGN->getFunction();
+ if (!F || F->isDeclaration() || F->doesNotRecurse())
+ return false;
+
+ // If all of the calls in F are identifiable and are to norecurse functions, F
+ // is norecurse. This check also detects self-recursion as F is not currently
+ // marked norecurse, so any called from F to F will not be marked norecurse.
+ if (std::all_of(CGN->begin(), CGN->end(),
+ [](const CallGraphNode::CallRecord &CR) {
+ Function *F = CR.second->getFunction();
+ return F && F->doesNotRecurse();
+ }))
+ // Function calls a potentially recursive function.
+ return setDoesNotRecurse(*F);
+
+ // We know that F is not obviously recursive, but we haven't been able to
+ // prove that it doesn't actually recurse. Add it to the Revisit list to try
+ // again top-down later.
+ Revisit.push_back(F);
+ return false;
+}
+
+static bool addNoRecurseAttrsTopDownOnly(Function *F) {
+ // If F is internal and all uses are in norecurse functions, then F is also
+ // norecurse.
+ if (F->doesNotRecurse())
+ return false;
+ if (F->hasInternalLinkage()) {
+ for (auto *U : F->users())
+ if (auto *I = dyn_cast<Instruction>(U)) {
+ if (!I->getParent()->getParent()->doesNotRecurse())
+ return false;
+ } else {
+ return false;
+ }
+ return setDoesNotRecurse(*F);
+ }
+ return false;
+}
+
bool FunctionAttrs::runOnSCC(CallGraphSCC &SCC) {
TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
bool Changed = false;
@@ -1826,6 +1890,19 @@ bool FunctionAttrs::runOnSCC(CallGraphSC
Changed |= addNoAliasAttrs(SCCNodes);
Changed |= addNonNullAttrs(SCCNodes, *TLI);
}
+
+ Changed |= addNoRecurseAttrs(SCC, Revisit);
+ return Changed;
+}
+bool FunctionAttrs::doFinalization(CallGraph &CG) {
+ bool Changed = false;
+ // When iterating over SCCs we visit functions in a bottom-up fashion. Some of
+ // the rules we have for identifying norecurse functions work best with a
+ // top-down walk, so look again at all the functions we previously marked as
+ // worth revisiting, in top-down order.
+ for (auto &F : reverse(Revisit))
+ if (F)
+ Changed |= addNoRecurseAttrsTopDownOnly(cast<Function>((Value*)F));
return Changed;
}
Modified: llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll (original)
+++ llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll Thu Nov 12 04:55:20 2015
@@ -30,7 +30,7 @@ define void @test1_yes(i32* %p) nounwind
ret void
}
-; CHECK: define void @test1_no(i32* %p) #1 {
+; CHECK: define void @test1_no(i32* %p) #3 {
define void @test1_no(i32* %p) nounwind {
call void @callee(i32* %p), !tbaa !2
ret void
@@ -72,9 +72,11 @@ define i32 @test3_no(i8* %p) nounwind {
declare void @callee(i32* %p) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1) nounwind
-; CHECK: attributes #0 = { nounwind readnone }
-; CHECK: attributes #1 = { nounwind }
+; CHECK: attributes #0 = { norecurse nounwind readnone }
+; CHECK: attributes #1 = { norecurse nounwind }
; CHECK: attributes #2 = { nounwind readonly }
+; CHECK: attributes #3 = { nounwind }
+; CHECK: attributes #4 = { argmemonly nounwind }
; Root note.
!0 = !{ }
Modified: llvm/trunk/test/Transforms/FunctionAttrs/2008-09-03-ReadNone.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/2008-09-03-ReadNone.ll?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/2008-09-03-ReadNone.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/2008-09-03-ReadNone.ll Thu Nov 12 04:55:20 2015
@@ -10,15 +10,16 @@ define i32 @f() {
ret i32 %tmp
}
-; CHECK: define i32 @g() #0
+; CHECK: define i32 @g() #1
define i32 @g() readonly {
ret i32 0
}
-; CHECK: define i32 @h() #0
+; CHECK: define i32 @h() #1
define i32 @h() readnone {
%tmp = load i32, i32* @x ; <i32> [#uses=1]
ret i32 %tmp
}
; CHECK: attributes #0 = { readnone }
+; CHECK: attributes #1 = { norecurse readnone }
Modified: llvm/trunk/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll Thu Nov 12 04:55:20 2015
@@ -4,7 +4,9 @@
@g = constant i32 1
define void @foo() {
-; CHECK: void @foo() {
+; CHECK: void @foo() #0 {
%tmp = load volatile i32, i32* @g
ret void
}
+
+; CHECK: attributes #0 = { norecurse }
Modified: llvm/trunk/test/Transforms/FunctionAttrs/atomic.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/atomic.ll?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/atomic.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/atomic.ll Thu Nov 12 04:55:20 2015
@@ -19,5 +19,5 @@ entry:
ret i32 %r
}
-; CHECK: attributes #0 = { readnone ssp uwtable }
-; CHECK: attributes #1 = { ssp uwtable }
+; CHECK: attributes #0 = { norecurse readnone ssp uwtable }
+; CHECK: attributes #1 = { norecurse ssp uwtable }
Added: llvm/trunk/test/Transforms/FunctionAttrs/norecurse.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/norecurse.ll?rev=252871&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/norecurse.ll (added)
+++ llvm/trunk/test/Transforms/FunctionAttrs/norecurse.ll Thu Nov 12 04:55:20 2015
@@ -0,0 +1,57 @@
+; RUN: opt < %s -basicaa -functionattrs -S | FileCheck %s
+
+; CHECK: define i32 @leaf() #0
+define i32 @leaf() {
+ ret i32 1
+}
+
+; CHECK: define i32 @self_rec() #1
+define i32 @self_rec() {
+ %a = call i32 @self_rec()
+ ret i32 4
+}
+
+; CHECK: define i32 @indirect_rec() #1
+define i32 @indirect_rec() {
+ %a = call i32 @indirect_rec2()
+ ret i32 %a
+}
+; CHECK: define i32 @indirect_rec2() #1
+define i32 @indirect_rec2() {
+ %a = call i32 @indirect_rec()
+ ret i32 %a
+}
+
+; CHECK: define i32 @extern() #1
+define i32 @extern() {
+ %a = call i32 @k()
+ ret i32 %a
+}
+declare i32 @k() readnone
+
+; CHECK: define internal i32 @called_by_norecurse() #0
+define internal i32 @called_by_norecurse() {
+ %a = call i32 @k()
+ ret i32 %a
+}
+define void @m() norecurse {
+ %a = call i32 @called_by_norecurse()
+ ret void
+}
+
+; CHECK: define internal i32 @called_by_norecurse_indirectly() #0
+define internal i32 @called_by_norecurse_indirectly() {
+ %a = call i32 @k()
+ ret i32 %a
+}
+define internal void @o() {
+ %a = call i32 @called_by_norecurse_indirectly()
+ ret void
+}
+define void @p() norecurse {
+ call void @o()
+ ret void
+}
+
+; CHECK: attributes #0 = { norecurse readnone }
+; CHECK: attributes #1 = { readnone }
Modified: llvm/trunk/test/Transforms/FunctionAttrs/optnone.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/optnone.ll?rev=252871&r1=252870&r2=252871&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/optnone.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/optnone.ll Thu Nov 12 04:55:20 2015
@@ -16,9 +16,11 @@ define void @test_optnone(i8* %p) noinli
declare i8 @strlen(i8*) noinline optnone
; CHECK-LABEL: @strlen
-; CHECK: (i8*) #1
+; CHECK: (i8*) #2
; CHECK-LABEL: attributes #0
-; CHECK: = { readnone }
+; CHECK: = { norecurse readnone }
; CHECK-LABEL: attributes #1
+; CHECK: = { noinline norecurse optnone }
+; CHECK-LABEL: attributes #2
; CHECK: = { noinline optnone }
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