[llvm] r367933 - [Attributor][Fix] Do not remove instructions during manifestation
Johannes Doerfert via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 5 14:35:02 PDT 2019
Author: jdoerfert
Date: Mon Aug 5 14:35:02 2019
New Revision: 367933
URL: http://llvm.org/viewvc/llvm-project?rev=367933&view=rev
Log:
[Attributor][Fix] Do not remove instructions during manifestation
When we remove instructions cached references could still be live. This
patch avoids removing invoke instructions that are replaced by calls and
instead keeps them around but in a dead block.
Modified:
llvm/trunk/include/llvm/Transforms/Utils/Local.h
llvm/trunk/lib/Transforms/IPO/Attributor.cpp
llvm/trunk/lib/Transforms/Utils/Local.cpp
llvm/trunk/test/Transforms/FunctionAttrs/liveness.ll
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=367933&r1=367932&r2=367933&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/Local.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/Local.h Mon Aug 5 14:35:02 2019
@@ -271,6 +271,12 @@ inline unsigned getKnownAlignment(Value
return getOrEnforceKnownAlignment(V, 0, DL, CxtI, AC, DT);
}
+/// Create a call that matches the invoke \p II in terms of arguments,
+/// attributes, debug information, etc. The call is not placed in a block and it
+/// will not have a name. The invoke instruction is not removed, nor are the
+/// uses replaced by the new call.
+CallInst *createCallMatchingInvoke(InvokeInst *II);
+
/// This function converts the specified invoek into a normall call.
void changeToCall(InvokeInst *II, DomTreeUpdater *DTU = nullptr);
Modified: llvm/trunk/lib/Transforms/IPO/Attributor.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/Attributor.cpp?rev=367933&r1=367932&r2=367933&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/Attributor.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/Attributor.cpp Mon Aug 5 14:35:02 2019
@@ -1577,6 +1577,11 @@ struct AAIsDeadFunction : AAIsDead, Bool
Instruction *SplitPos = I->getNextNode();
if (auto *II = dyn_cast<InvokeInst>(I)) {
+ // If we keep the invoke the split position is at the beginning of the
+ // normal desitination block (it invokes a noreturn function after all).
+ BasicBlock *NormalDestBB = II->getNormalDest();
+ SplitPos = &NormalDestBB->front();
+
/// Invoke is replaced with a call and unreachable is placed after it if
/// the callee is nounwind and noreturn. Otherwise, we keep the invoke
/// and only place an unreachable in the normal successor.
@@ -1587,17 +1592,26 @@ struct AAIsDeadFunction : AAIsDead, Bool
(AANoUnw && AANoUnw->isAssumedNoUnwind())) {
LLVM_DEBUG(dbgs()
<< "[AAIsDead] Replace invoke with call inst\n");
- changeToCall(II);
- changeToUnreachable(BB->getTerminator(), /* UseLLVMTrap */ false);
- continue;
+ // We do not need an invoke (II) but instead want a call followed
+ // by an unreachable. However, we do not remove II as other
+ // abstract attributes might have it cached as part of their
+ // results. Given that we modify the CFG anyway, we simply keep II
+ // around but in a new dead block. To avoid II being live through
+ // a different edge we have to ensure the block we place it in is
+ // only reached from the current block of II and then not reached
+ // at all when we insert the unreachable.
+ SplitBlockPredecessors(NormalDestBB, {BB}, ".i2c");
+ CallInst *CI = createCallMatchingInvoke(II);
+ CI->insertBefore(II);
+ CI->takeName(II);
+ II->replaceAllUsesWith(CI);
+ SplitPos = CI->getNextNode();
}
}
}
-
- BB = II->getNormalDest();
- SplitPos = &BB->front();
}
+ BB = SplitPos->getParent();
SplitBlock(BB, SplitPos);
changeToUnreachable(BB->getTerminator(), /* UseLLVMTrap */ false);
HasChanged = ChangeStatus::CHANGED;
Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=367933&r1=367932&r2=367933&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/Local.cpp Mon Aug 5 14:35:02 2019
@@ -1933,18 +1933,24 @@ unsigned llvm::changeToUnreachable(Instr
return NumInstrsRemoved;
}
-/// changeToCall - Convert the specified invoke into a normal call.
-void llvm::changeToCall(InvokeInst *II, DomTreeUpdater *DTU) {
- SmallVector<Value*, 8> Args(II->arg_begin(), II->arg_end());
+CallInst *llvm::createCallMatchingInvoke(InvokeInst *II) {
+ SmallVector<Value *, 8> Args(II->arg_begin(), II->arg_end());
SmallVector<OperandBundleDef, 1> OpBundles;
II->getOperandBundlesAsDefs(OpBundles);
- CallInst *NewCall = CallInst::Create(
- II->getFunctionType(), II->getCalledValue(), Args, OpBundles, "", II);
- NewCall->takeName(II);
+ CallInst *NewCall = CallInst::Create(II->getFunctionType(),
+ II->getCalledValue(), Args, OpBundles);
NewCall->setCallingConv(II->getCallingConv());
NewCall->setAttributes(II->getAttributes());
NewCall->setDebugLoc(II->getDebugLoc());
NewCall->copyMetadata(*II);
+ return NewCall;
+}
+
+/// changeToCall - Convert the specified invoke into a normal call.
+void llvm::changeToCall(InvokeInst *II, DomTreeUpdater *DTU) {
+ CallInst *NewCall = createCallMatchingInvoke(II);
+ NewCall->takeName(II);
+ NewCall->insertBefore(II);
II->replaceAllUsesWith(NewCall);
// Follow the call by a branch to the normal destination.
Modified: llvm/trunk/test/Transforms/FunctionAttrs/liveness.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/FunctionAttrs/liveness.ll?rev=367933&r1=367932&r2=367933&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/liveness.ll (original)
+++ llvm/trunk/test/Transforms/FunctionAttrs/liveness.ll Mon Aug 5 14:35:02 2019
@@ -184,9 +184,14 @@ cond.true:
call void @normal_call()
%call = invoke i32 @foo_noreturn_nounwind() to label %continue
unwind label %cleanup
- ; CHECK: call i32 @foo_noreturn_nounwind()
+ ; CHECK: call void @normal_call()
+ ; CHECK-NEXT: call i32 @foo_noreturn_nounwind()
; CHECK-NEXT: unreachable
+ ; We keep the invoke around as other attributes might have references to it.
+ ; CHECK: cond.true.split: ; No predecessors!
+ ; CHECK-NEXT: invoke i32 @foo_noreturn_nounwind()
+
cond.false: ; preds = %entry
call void @normal_call()
%call1 = call i32 @bar()
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