[llvm] r277691 - Reinstate "[CloneFunction] Don't remove side effecting calls"

Mikael Holmén via llvm-commits llvm-commits at lists.llvm.org
Mon Aug 22 02:24:03 PDT 2016


Hi,

On 08/19/2016 06:47 PM, David Majnemer wrote:
>
>
> On Fri, Aug 19, 2016 at 12:56 AM, Mikael Holmén
> <mikael.holmen at ericsson.com <mailto:mikael.holmen at ericsson.com>> wrote:
>
>     Hi David and Hans,
>
>     We've seen a crash with this commit. The below is a failed
>     assertion, but with a variant of the input I've also seen a
>     segmentation violation.
>
>
> Should be fixed with r279268.

Yes, now I don't see the assertion and I don't get the SEGV for the 
other example either.

Great!
/Mikael

>
>
>
>     (I don't have a reproducer for the SEGV when compiling for any
>     in-tree targets but I can try to get one if it still crashes after
>     the assertion problem is fixed.)
>
>     opt -S -inline -functionattrs red.ll
>
>     gives
>
>     opt: ../lib/Analysis/CallGraph.cpp:205: void
>     llvm::CallGraphNode::removeCallEdgeFor(llvm::CallSite): Assertion `I
>     != CalledFunctions.end() && "Cannot find callsite to remove!"' failed.
>     #0 0x0000000001831288 llvm::sys::PrintStackTrace(llvm::raw_ostream&)
>     (build-all/bin/opt+0x1831288)
>     #1 0x0000000001831e66 SignalHandler(int) (build-all/bin/opt+0x1831e66)
>     #2 0x00007f26a8925330 __restore_rt
>     (/lib/x86_64-linux-gnu/libpthread.so.0+0x10330)
>     #3 0x00007f26a7518c37 gsignal
>     /build/eglibc-oGUzwX/eglibc-2.19/signal/../nptl/sysdeps/unix/sysv/linux/raise.c:56:0
>     #4 0x00007f26a751c028 abort
>     /build/eglibc-oGUzwX/eglibc-2.19/stdlib/abort.c:91:0
>     #5 0x00007f26a7511bf6 __assert_fail_base
>     /build/eglibc-oGUzwX/eglibc-2.19/assert/assert.c:92:0
>     #6 0x00007f26a7511ca2 (/lib/x86_64-linux-gnu/libc.so.6+0x2fca2)
>     #7 0x0000000000f6a4de
>     llvm::CallGraphNode::removeCallEdgeFor(llvm::CallSite)
>     (build-all/bin/opt+0xf6a4de)
>     #8 0x000000000186d13a llvm::InlineFunction(llvm::CallSite,
>     llvm::InlineFunctionInfo&, llvm::AAResults*, bool)
>     (build-all/bin/opt+0x186d13a)
>     #9 0x00000000014b4750 inlineCallsImpl(llvm::CallGraphSCC&,
>     llvm::CallGraph&, std::function<llvm::AssumptionCache&
>     (llvm::Function&)>, llvm::ProfileSummaryInfo*,
>     llvm::TargetLibraryInfo&, bool, std::function<llvm::InlineCost
>     (llvm::CallSite)>, std::function<llvm::AAResults&
>     (llvm::Function&)>, llvm::ImportedFunctionsInliningStatistics&)
>     (build-all/bin/opt+0x14b4750)
>     #10 0x00000000014b2248
>     llvm::Inliner::inlineCalls(llvm::CallGraphSCC&)
>     (build-all/bin/opt+0x14b2248)
>     #11 0x00000000014b1fd2 llvm::Inliner::runOnSCC(llvm::CallGraphSCC&)
>     (build-all/bin/opt+0x14b1fd2)
>     #12 0x0000000000f6d823 (anonymous
>     namespace)::CGPassManager::runOnModule(llvm::Module&)
>     (build-all/bin/opt+0xf6d823)
>     #13 0x000000000141ef25
>     llvm::legacy::PassManagerImpl::run(llvm::Module&)
>     (build-all/bin/opt+0x141ef25)
>     #14 0x0000000000667025 main (build-all/bin/opt+0x667025)
>     #15 0x00007f26a7503f45 __libc_start_main
>     /build/eglibc-oGUzwX/eglibc-2.19/csu/libc-start.c:321:0
>     #16 0x0000000000656675 _start (build-all/bin/opt+0x656675)
>     Stack dump:
>     0.      Program arguments: build-all/bin/opt -S -inline
>     -functionattrs red.ll
>     1.      Running pass 'CallGraph Pass Manager' on module 'red.ll'.
>     Abort
>
>     -debug printouts:
>
>     Inliner visiting SCC: f1: 0 call sites.
>     CGSCCPASSMGR: Refreshing SCC with 1 nodes:
>     Call graph node for function: 'f1'<<0x4d327d0>>  #uses=2
>
>     CGSCCPASSMGR: SCC Refresh didn't change call graph.
>     Inliner visiting SCC: f2: 0 call sites.
>     CGSCCPASSMGR: Refreshing SCC with 1 nodes:
>     Call graph node for function: 'f2'<<0x4d32c60>>  #uses=2
>
>     CGSCCPASSMGR: SCC Refresh didn't change call graph.
>     Inliner visiting SCC: f3: 0 call sites.
>     CGSCCPASSMGR: Refreshing SCC with 1 nodes:
>     Call graph node for function: 'f3'<<0x4d32d30>>  #uses=2
>
>     CGSCCPASSMGR: SCC Refresh didn't change call graph.
>     Inliner visiting SCC: f4: 3 call sites.
>           Analyzing call of f3...
>           NumConstantArgs: 0
>           NumConstantOffsetPtrArgs: 0
>           NumAllocaArgs: 0
>           NumConstantPtrCmps: 0
>           NumConstantPtrDiffs: 0
>           NumInstructionsSimplified: 1
>           NumInstructions: 1
>           SROACostSavings: 0
>           SROACostSavingsLost: 0
>           ContainsNoDuplicateCall: 0
>           Cost: 0
>           Threshold: 337
>         Inlining: cost=0, thres=337, Call:   call void @f3()
>           Analyzing call of f1...
>           NumConstantArgs: 1
>           NumConstantOffsetPtrArgs: 0
>           NumAllocaArgs: 0
>           NumConstantPtrCmps: 0
>           NumConstantPtrDiffs: 0
>           NumInstructionsSimplified: 5
>           NumInstructions: 6
>           SROACostSavings: 0
>           SROACostSavingsLost: 0
>           ContainsNoDuplicateCall: 0
>           Cost: -5
>           Threshold: 225
>         Inlining: cost=-5, thres=225, Call:   call void @f1(i16 0, i16
>     %_tmp29)
>           Analyzing call of f2...
>           NumConstantArgs: 1
>           NumConstantOffsetPtrArgs: 0
>           NumAllocaArgs: 0
>           NumConstantPtrCmps: 0
>           NumConstantPtrDiffs: 0
>           NumInstructionsSimplified: 1
>           NumInstructions: 1
>           SROACostSavings: 0
>           SROACostSavingsLost: 0
>           ContainsNoDuplicateCall: 0
>           Cost: -5
>           Threshold: 337
>         Inlining: cost=-5, thres=337, Call:   %_tmp29 = call i16 @f2(i16 1)
>     opt: ../lib/Analysis/CallGraph.cpp:205: void
>     llvm::CallGraphNode::removeCallEdgeFor(llvm::CallSite): Assertion `I
>     != CalledFunctions.end() && "Cannot find callsite to remove!"' failed.
>
>     Regards,
>     Mikael
>
>
>     On 08/05/2016 12:52 AM, Hans Wennborg via llvm-commits wrote:
>
>         Thanks! I grabbed r277773 as well just to be sure :-) Merged in
>         r277781.
>
>         Since this is close to ToT, please let me know if any problems
>         come up
>         that require follow-ups.
>
>         Cheers,
>         Hans
>
>         On Thu, Aug 4, 2016 at 10:59 AM, David Majnemer
>         <david.majnemer at gmail.com <mailto:david.majnemer at gmail.com>> wrote:
>
>             Yes along with r277693.
>
>             On Thu, Aug 4, 2016 at 10:13 AM, Hans Wennborg
>             <hans at chromium.org <mailto:hans at chromium.org>> wrote:
>
>
>                 Should we merge this to 3.9?
>
>                 On Wed, Aug 3, 2016 at 9:24 PM, David Majnemer via
>                 llvm-commits
>                 <llvm-commits at lists.llvm.org
>                 <mailto:llvm-commits at lists.llvm.org>> wrote:
>
>                     Author: majnemer
>                     Date: Wed Aug  3 23:24:02 2016
>                     New Revision: 277691
>
>                     URL:
>                     http://llvm.org/viewvc/llvm-project?rev=277691&view=rev
>                     <http://llvm.org/viewvc/llvm-project?rev=277691&view=rev>
>                     Log:
>                     Reinstate "[CloneFunction] Don't remove side
>                     effecting calls"
>
>                     This reinstates r277611 + r277614 and reverts
>                     r277642.  A cast_or_null
>                     should have been a dyn_cast_or_null.
>
>                     Modified:
>                         llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>                         llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
>
>                     llvm/trunk/test/Transforms/Inline/inline_constprop.ll
>
>                     Modified:
>                     llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>                     URL:
>                     http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=277691&r1=277690&r2=277691&view=diff
>                     <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=277691&r1=277690&r2=277691&view=diff>
>
>                     ==============================================================================
>                     --- llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>                     (original)
>                     +++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp
>                     Wed Aug  3 23:24:02
>                     2016
>                     @@ -4356,7 +4356,8 @@ static bool
>                     replaceAndRecursivelySimplif
>
>                          // Gracefully handle edge cases where the
>                     instruction is not wired
>                     into any
>                          // parent block.
>                     -    if (I->getParent())
>                     +    if (I->getParent() && !I->isEHPad() &&
>                     !isa<TerminatorInst>(I) &&
>                     +        !I->mayHaveSideEffects())
>                            I->eraseFromParent();
>                        } else {
>                          Worklist.insert(I);
>                     @@ -4384,7 +4385,8 @@ static bool
>                     replaceAndRecursivelySimplif
>
>                          // Gracefully handle edge cases where the
>                     instruction is not wired
>                     into any
>                          // parent block.
>                     -    if (I->getParent())
>                     +    if (I->getParent() && !I->isEHPad() &&
>                     !isa<TerminatorInst>(I) &&
>                     +        !I->mayHaveSideEffects())
>                            I->eraseFromParent();
>                        }
>                        return Simplified;
>
>                     Modified:
>                     llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
>                     URL:
>                     http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp?rev=277691&r1=277690&r2=277691&view=diff
>                     <http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp?rev=277691&r1=277690&r2=277691&view=diff>
>
>                     ==============================================================================
>                     ---
>                     llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
>                     (original)
>                     +++
>                     llvm/trunk/lib/Transforms/Utils/CloneFunction.cpp
>                     Wed Aug  3
>                     23:24:02 2016
>                     @@ -14,6 +14,7 @@
>
>                     //===----------------------------------------------------------------------===//
>
>                      #include "llvm/Transforms/Utils/Cloning.h"
>                     +#include "llvm/ADT/SetVector.h"
>                      #include "llvm/ADT/SmallVector.h"
>                      #include "llvm/Analysis/ConstantFolding.h"
>                      #include "llvm/Analysis/InstructionSimplify.h"
>                     @@ -552,9 +553,39 @@ void
>                     llvm::CloneAndPruneIntoFromInst(Fun
>                        // two PHINodes, the iteration over the old PHIs
>                     remains valid, and
>                     the
>                        // mapping will just map us to the new node
>                     (which may not even be a
>                     PHI
>                        // node).
>                     +  const DataLayout &DL =
>                     NewFunc->getParent()->getDataLayout();
>                     +  SmallSetVector<const Value *, 8> Worklist;
>                        for (unsigned Idx = 0, Size =
>                     PHIToResolve.size(); Idx != Size;
>                     ++Idx)
>                     -    if (PHINode *PN =
>                     dyn_cast<PHINode>(VMap[PHIToResolve[Idx]]))
>                     -      recursivelySimplifyInstruction(PN);
>                     +    if (isa<PHINode>(VMap[PHIToResolve[Idx]]))
>                     +      Worklist.insert(PHIToResolve[Idx]);
>                     +
>                     +  // Note that we must test the size on each
>                     iteration, the worklist
>                     can grow.
>                     +  for (unsigned Idx = 0; Idx != Worklist.size();
>                     ++Idx) {
>                     +    const Value *OrigV = Worklist[Idx];
>                     +    auto *I =
>                     cast_or_null<Instruction>(VMap.lookup(OrigV));
>                     +    if (!I)
>                     +      continue;
>                     +
>                     +    // See if this instruction simplifies.
>                     +    Value *SimpleV = SimplifyInstruction(I, DL);
>                     +    if (!SimpleV)
>                     +      continue;
>                     +
>                     +    // Stash away all the uses of the old
>                     instruction so we can check
>                     them for
>                     +    // recursive simplifications after a RAUW. This
>                     is cheaper than
>                     checking all
>                     +    // uses of To on the recursive step in most cases.
>                     +    for (const User *U : OrigV->users())
>                     +      Worklist.insert(cast<Instruction>(U));
>                     +
>                     +    // Replace the instruction with its simplified
>                     value.
>                     +    I->replaceAllUsesWith(SimpleV);
>                     +
>                     +    // If the original instruction had no side
>                     effects, remove it.
>                     +    if (isInstructionTriviallyDead(I))
>                     +      I->eraseFromParent();
>                     +    else
>                     +      VMap[OrigV] = I;
>                     +  }
>
>                        // Now that the inlined function body has been
>                     fully constructed, go
>                     through
>                        // and zap unconditional fall-through branches.
>                     This happens all the
>                     time when
>
>                     Modified:
>                     llvm/trunk/test/Transforms/Inline/inline_constprop.ll
>                     URL:
>                     http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/inline_constprop.ll?rev=277691&r1=277690&r2=277691&view=diff
>                     <http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/inline_constprop.ll?rev=277691&r1=277690&r2=277691&view=diff>
>
>                     ==============================================================================
>                     ---
>                     llvm/trunk/test/Transforms/Inline/inline_constprop.ll (original)
>                     +++
>                     llvm/trunk/test/Transforms/Inline/inline_constprop.ll Wed
>                     Aug  3
>                     23:24:02 2016
>                     @@ -279,3 +279,25 @@ return:
>                        %retval.0 = phi i32* [ %b, %if.end3 ], [ %a,
>                     %if.then ]
>                        ret i32* %retval.0
>                      }
>                     +
>                     +declare i32 @PR28802.external(i32 returned %p1)
>                     +
>                     +define internal i32 @PR28802.callee() {
>                     +entry:
>                     +  br label %cont
>                     +
>                     +cont:
>                     +  %0 = phi i32 [ 0, %entry ]
>                     +  %call = call i32 @PR28802.external(i32 %0)
>                     +  ret i32 %call
>                     +}
>                     +
>                     +define i32 @PR28802() {
>                     +entry:
>                     +  %call = call i32 @PR28802.callee()
>                     +  ret i32 %call
>                     +}
>                     +
>                     +; CHECK-LABEL: define i32 @PR28802(
>                     +; CHECK: call i32 @PR28802.external(i32 0)
>                     +; CHECK: ret i32 0
>
>
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