[llvm] r304275 - [CFLAA] Add missing break; note things are broken.
George Burgess IV via llvm-commits
llvm-commits at lists.llvm.org
Tue May 30 19:35:26 PDT 2017
Author: gbiv
Date: Tue May 30 21:35:26 2017
New Revision: 304275
URL: http://llvm.org/viewvc/llvm-project?rev=304275&view=rev
Log:
[CFLAA] Add missing break; note things are broken.
Thanks to Galina Kistanova for finding the missing break!
When trying to make a test for this, I realized our logic for handling
extractvalue/insertvalue/... is somewhat broken. This makes constructing
a test-case for this missing break nontrivial.
Added:
llvm/trunk/test/Analysis/CFLAliasAnalysis/Andersen/struct.ll
Modified:
llvm/trunk/lib/Analysis/CFLGraph.h
Modified: llvm/trunk/lib/Analysis/CFLGraph.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/CFLGraph.h?rev=304275&r1=304274&r2=304275&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/CFLGraph.h (original)
+++ llvm/trunk/lib/Analysis/CFLGraph.h Tue May 30 21:35:26 2017
@@ -210,6 +210,11 @@ template <typename CFLAA> class CFLGraph
void addDerefEdge(Value *From, Value *To, bool IsRead) {
assert(From != nullptr && To != nullptr);
+ // FIXME: This is subtly broken, due to how we model some instructions
+ // (e.g. extractvalue, extractelement) as loads. Since those take
+ // non-pointer operands, we'll entirely skip adding edges for those.
+ //
+ // addAssignEdge seems to have a similar issue with insertvalue, etc.
if (!From->getType()->isPointerTy() || !To->getType()->isPointerTy())
return;
addNode(From);
@@ -540,6 +545,7 @@ template <typename CFLAA> class CFLGraph
case Instruction::ExtractValue: {
auto *Ptr = CE->getOperand(0);
addLoadEdge(Ptr, CE);
+ break;
}
case Instruction::ShuffleVector: {
auto *From1 = CE->getOperand(0);
Added: llvm/trunk/test/Analysis/CFLAliasAnalysis/Andersen/struct.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/CFLAliasAnalysis/Andersen/struct.ll?rev=304275&view=auto
==============================================================================
--- llvm/trunk/test/Analysis/CFLAliasAnalysis/Andersen/struct.ll (added)
+++ llvm/trunk/test/Analysis/CFLAliasAnalysis/Andersen/struct.ll Tue May 30 21:35:26 2017
@@ -0,0 +1,18 @@
+; Ensures that our struct ops are sane.
+
+; RUN: opt < %s -disable-basicaa -cfl-anders-aa -aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -aa-pipeline=cfl-anders-aa -passes=aa-eval -print-all-alias-modref-info -disable-output 2>&1 | FileCheck %s
+
+; Since we ignore non-pointer values, we effectively ignore extractvalue
+; instructions. This means that %c "doesn't exist" in test_structure's graph,
+; so we currently get MayAlias.
+; XFAIL: *
+
+; CHECK-LABEL: Function: test_structure
+; CHECK: NoAlias: i64** %c, { i64**, i64** }* %a
+define void @test_structure() {
+ %a = alloca {i64**, i64**}, align 8
+ %b = load {i64**, i64**}, {i64**, i64**}* %a
+ %c = extractvalue {i64**, i64**} %b, 0
+ ret void
+}
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