[llvm] r309291 - All libcalls should be considered to be GC-leaf functions.
Daniel Neilson via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 27 09:49:39 PDT 2017
Author: dneilson
Date: Thu Jul 27 09:49:39 2017
New Revision: 309291
URL: http://llvm.org/viewvc/llvm-project?rev=309291&view=rev
Log:
All libcalls should be considered to be GC-leaf functions.
Summary:
It is possible for some passes to materialize a call to a libcall (ex: ldexp, exp2, etc),
but these passes will not mark the call as a gc-leaf-function. All libcalls are
actually gc-leaf-functions, so we change llvm::callsGCLeafFunction() to tell us that
available libcalls are equivalent to gc-leaf-function calls.
Reviewers: sanjoy, anna, reames
Reviewed By: anna
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35840
Added:
llvm/trunk/test/Transforms/PlaceSafepoints/libcall.ll
llvm/trunk/test/Transforms/RewriteStatepointsForGC/libcall.ll
Modified:
llvm/trunk/include/llvm/Transforms/Utils/Local.h
llvm/trunk/lib/Transforms/Scalar/PlaceSafepoints.cpp
llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
llvm/trunk/lib/Transforms/Utils/Local.cpp
Modified: llvm/trunk/include/llvm/Transforms/Utils/Local.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/Local.h?rev=309291&r1=309290&r2=309291&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Thu Jul 27 09:49:39 2017
@@ -378,7 +378,7 @@ unsigned replaceDominatedUsesWith(Value
///
/// Most passes can and should ignore this information, and it is only used
/// during lowering by the GC infrastructure.
-bool callsGCLeafFunction(ImmutableCallSite CS);
+bool callsGCLeafFunction(ImmutableCallSite CS, const TargetLibraryInfo &TLI);
/// Copy a nonnull metadata node to a new load instruction.
///
Modified: llvm/trunk/lib/Transforms/Scalar/PlaceSafepoints.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/PlaceSafepoints.cpp?rev=309291&r1=309290&r2=309291&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/PlaceSafepoints.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/PlaceSafepoints.cpp Thu Jul 27 09:49:39 2017
@@ -54,6 +54,7 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/IntrinsicInst.h"
@@ -113,6 +114,7 @@ struct PlaceBackedgeSafepointsImpl : pub
ScalarEvolution *SE = nullptr;
DominatorTree *DT = nullptr;
LoopInfo *LI = nullptr;
+ TargetLibraryInfo *TLI = nullptr;
PlaceBackedgeSafepointsImpl(bool CallSafepoints = false)
: FunctionPass(ID), CallSafepointsEnabled(CallSafepoints) {
@@ -131,6 +133,7 @@ struct PlaceBackedgeSafepointsImpl : pub
SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+ TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
for (Loop *I : *LI) {
runOnLoopAndSubLoops(I);
}
@@ -141,6 +144,7 @@ struct PlaceBackedgeSafepointsImpl : pub
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<ScalarEvolutionWrapperPass>();
AU.addRequired<LoopInfoWrapperPass>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
// We no longer modify the IR at all in this pass. Thus all
// analysis are preserved.
AU.setPreservesAll();
@@ -165,6 +169,7 @@ struct PlaceSafepoints : public Function
// We modify the graph wholesale (inlining, block insertion, etc). We
// preserve nothing at the moment. We could potentially preserve dom tree
// if that was worth doing
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
}
};
}
@@ -174,10 +179,11 @@ struct PlaceSafepoints : public Function
// callers job.
static void
InsertSafepointPoll(Instruction *InsertBefore,
- std::vector<CallSite> &ParsePointsNeeded /*rval*/);
+ std::vector<CallSite> &ParsePointsNeeded /*rval*/,
+ const TargetLibraryInfo &TLI);
-static bool needsStatepoint(const CallSite &CS) {
- if (callsGCLeafFunction(CS))
+static bool needsStatepoint(const CallSite &CS, const TargetLibraryInfo &TLI) {
+ if (callsGCLeafFunction(CS, TLI))
return false;
if (CS.isCall()) {
CallInst *call = cast<CallInst>(CS.getInstruction());
@@ -194,7 +200,8 @@ static bool needsStatepoint(const CallSi
/// answer; i.e. false is always valid.
static bool containsUnconditionalCallSafepoint(Loop *L, BasicBlock *Header,
BasicBlock *Pred,
- DominatorTree &DT) {
+ DominatorTree &DT,
+ const TargetLibraryInfo &TLI) {
// In general, we're looking for any cut of the graph which ensures
// there's a call safepoint along every edge between Header and Pred.
// For the moment, we look only for the 'cuts' that consist of a single call
@@ -217,7 +224,7 @@ static bool containsUnconditionalCallSaf
// unconditional poll. In practice, this is only a theoretical concern
// since we don't have any methods with conditional-only safepoint
// polls.
- if (needsStatepoint(CS))
+ if (needsStatepoint(CS, TLI))
return true;
}
@@ -321,7 +328,7 @@ bool PlaceBackedgeSafepointsImpl::runOnL
continue;
}
if (CallSafepointsEnabled &&
- containsUnconditionalCallSafepoint(L, Header, Pred, *DT)) {
+ containsUnconditionalCallSafepoint(L, Header, Pred, *DT, *TLI)) {
// Note: This is only semantically legal since we won't do any further
// IPO or inlining before the actual call insertion.. If we hadn't, we
// might latter loose this call safepoint.
@@ -472,6 +479,9 @@ bool PlaceSafepoints::runOnFunction(Func
if (!shouldRewriteFunction(F))
return false;
+ const TargetLibraryInfo &TLI =
+ getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+
bool Modified = false;
// In various bits below, we rely on the fact that uses are reachable from
@@ -578,7 +588,7 @@ bool PlaceSafepoints::runOnFunction(Func
// safepoint polls themselves.
for (Instruction *PollLocation : PollsNeeded) {
std::vector<CallSite> RuntimeCalls;
- InsertSafepointPoll(PollLocation, RuntimeCalls);
+ InsertSafepointPoll(PollLocation, RuntimeCalls, TLI);
ParsePointNeeded.insert(ParsePointNeeded.end(), RuntimeCalls.begin(),
RuntimeCalls.end());
}
@@ -610,7 +620,8 @@ INITIALIZE_PASS_END(PlaceSafepoints, "pl
static void
InsertSafepointPoll(Instruction *InsertBefore,
- std::vector<CallSite> &ParsePointsNeeded /*rval*/) {
+ std::vector<CallSite> &ParsePointsNeeded /*rval*/,
+ const TargetLibraryInfo &TLI) {
BasicBlock *OrigBB = InsertBefore->getParent();
Module *M = InsertBefore->getModule();
assert(M && "must be part of a module");
@@ -669,7 +680,7 @@ InsertSafepointPoll(Instruction *InsertB
assert(ParsePointsNeeded.empty());
for (auto *CI : Calls) {
// No safepoint needed or wanted
- if (!needsStatepoint(CI))
+ if (!needsStatepoint(CI, TLI))
continue;
// These are likely runtime calls. Should we assert that via calling
Modified: llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp?rev=309291&r1=309290&r2=309291&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/RewriteStatepointsForGC.cpp Thu Jul 27 09:49:39 2017
@@ -19,6 +19,7 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
@@ -103,6 +104,7 @@ struct RewriteStatepointsForGC : public
// else. We could in theory preserve a lot more analyses here.
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<TargetTransformInfoWrapperPass>();
+ AU.addRequired<TargetLibraryInfoWrapperPass>();
}
/// The IR fed into RewriteStatepointsForGC may have had attributes and
@@ -2419,10 +2421,12 @@ bool RewriteStatepointsForGC::runOnFunct
DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
TargetTransformInfo &TTI =
getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
+ const TargetLibraryInfo &TLI =
+ getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
- auto NeedsRewrite = [](Instruction &I) {
+ auto NeedsRewrite = [&TLI](Instruction &I) {
if (ImmutableCallSite CS = ImmutableCallSite(&I))
- return !callsGCLeafFunction(CS) && !isStatepoint(CS);
+ return !callsGCLeafFunction(CS, TLI) && !isStatepoint(CS);
return false;
};
Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=309291&r1=309290&r2=309291&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/Local.cpp Thu Jul 27 09:49:39 2017
@@ -1832,7 +1832,8 @@ unsigned llvm::replaceDominatedUsesWith(
return ::replaceDominatedUsesWith(From, To, BB, ProperlyDominates);
}
-bool llvm::callsGCLeafFunction(ImmutableCallSite CS) {
+bool llvm::callsGCLeafFunction(ImmutableCallSite CS,
+ const TargetLibraryInfo &TLI) {
// Check if the function is specifically marked as a gc leaf function.
if (CS.hasFnAttr("gc-leaf-function"))
return true;
@@ -1846,6 +1847,14 @@ bool llvm::callsGCLeafFunction(Immutable
IID != Intrinsic::experimental_deoptimize;
}
+ // Lib calls can be materialized by some passes, and won't be
+ // marked as 'gc-leaf-function.' All available Libcalls are
+ // GC-leaf.
+ LibFunc LF;
+ if (TLI.getLibFunc(CS, LF)) {
+ return TLI.has(LF);
+ }
+
return false;
}
Added: llvm/trunk/test/Transforms/PlaceSafepoints/libcall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PlaceSafepoints/libcall.ll?rev=309291&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PlaceSafepoints/libcall.ll (added)
+++ llvm/trunk/test/Transforms/PlaceSafepoints/libcall.ll Thu Jul 27 09:49:39 2017
@@ -0,0 +1,37 @@
+; RUN: opt -S -place-safepoints < %s | FileCheck %s
+
+; Libcalls will not contain a safepoint poll, so check that we insert
+; a safepoint in a loop containing a libcall.
+declare double @ldexp(double %x, i32 %n) nounwind readnone
+define double @test_libcall(double %x) gc "statepoint-example" {
+; CHECK-LABEL: test_libcall
+
+entry:
+; CHECK: entry
+; CHECK-NEXT: call void @do_safepoint
+; CHECK-NEXT: br label %loop
+ br label %loop
+
+loop:
+; CHECK: loop
+; CHECK-NEXT: %x_loop = phi double [ %x, %entry ], [ %x_exp, %loop ]
+; CHECK-NEXT: %x_exp = call double @ldexp(double %x_loop, i32 5)
+; CHECK-NEXT: %done = fcmp ogt double %x_exp, 1.5
+; CHECK-NEXT: call void @do_safepoint
+ %x_loop = phi double [ %x, %entry ], [ %x_exp, %loop ]
+ %x_exp = call double @ldexp(double %x_loop, i32 5) nounwind readnone
+ %done = fcmp ogt double %x_exp, 1.5
+ br i1 %done, label %end, label %loop
+end:
+ %x_end = phi double [%x_exp, %loop]
+ ret double %x_end
+}
+
+; This function is inlined when inserting a poll.
+declare void @do_safepoint()
+define void @gc.safepoint_poll() {
+; CHECK-LABEL: gc.safepoint_poll
+entry:
+ call void @do_safepoint()
+ ret void
+}
Added: llvm/trunk/test/Transforms/RewriteStatepointsForGC/libcall.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/RewriteStatepointsForGC/libcall.ll?rev=309291&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/RewriteStatepointsForGC/libcall.ll (added)
+++ llvm/trunk/test/Transforms/RewriteStatepointsForGC/libcall.ll Thu Jul 27 09:49:39 2017
@@ -0,0 +1,14 @@
+; A call to a libcall function is not a statepoint.
+; This test verifies that calls to libcalls functions do not get converted to
+; statepoint calls.
+; RUN: opt -S -rewrite-statepoints-for-gc < %s | FileCheck %s
+
+declare double @ldexp(double %x, i32 %n) nounwind readnone
+
+define double @test_libcall(double %x) gc "statepoint-example" {
+; CHECK-LABEL: test_libcall
+; CHECK-NEXT: %res = call double @ldexp(double %x, i32 5)
+; CHECK-NEXT: ret double %res
+ %res = call double @ldexp(double %x, i32 5) nounwind readnone
+ ret double %res
+}
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