[llvm] 4dcc029 - [ObjC][ARC] Keep track of phis that have been discovered to avoid an
Akira Hatanaka via llvm-commits
llvm-commits at lists.llvm.org
Fri Feb 7 20:33:44 PST 2020
Author: Akira Hatanaka
Date: 2020-02-07T20:33:11-08:00
New Revision: 4dcc029edbe4bd5e30d4f0cdcf123ea4ed2b6418
URL: https://github.com/llvm/llvm-project/commit/4dcc029edbe4bd5e30d4f0cdcf123ea4ed2b6418
DIFF: https://github.com/llvm/llvm-project/commit/4dcc029edbe4bd5e30d4f0cdcf123ea4ed2b6418.diff
LOG: [ObjC][ARC] Keep track of phis that have been discovered to avoid an
infinite loop
This fixes a bug introduced in 6770fbb31450db15d8d4a2ac7f0ce70eaf2acc5f.
rdar://problem/59137105
Added:
Modified:
llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
llvm/test/Transforms/ObjCARC/inert-global.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index 7dbb95faaf85..adab7491d27a 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -879,7 +879,7 @@ void ObjCARCOpt::OptimizeIndividualCalls(Function &F) {
/// This function returns true if the value is inert. An ObjC ARC runtime call
/// taking an inert operand can be safely deleted.
-static bool isInertARCValue(Value *V) {
+static bool isInertARCValue(Value *V, SmallPtrSet<Value *, 1> &VisitedPhis) {
V = V->stripPointerCasts();
if (IsNullOrUndef(V))
@@ -891,9 +891,12 @@ static bool isInertARCValue(Value *V) {
return true;
if (auto PN = dyn_cast<PHINode>(V)) {
+ // Ignore this phi if it has already been discovered.
+ if (!VisitedPhis.insert(PN).second)
+ return true;
// Look through phis's operands.
for (Value *Opnd : PN->incoming_values())
- if (!isInertARCValue(Opnd))
+ if (!isInertARCValue(Opnd, VisitedPhis))
return false;
return true;
}
@@ -907,8 +910,10 @@ void ObjCARCOpt::OptimizeIndividualCallImpl(
LLVM_DEBUG(dbgs() << "Visiting: Class: " << Class << "; " << *Inst << "\n");
// We can delete this call if it takes an inert value.
+ SmallPtrSet<Value *, 1> VisitedPhis;
+
if (IsNoopOnGlobal(Class))
- if (isInertARCValue(Inst->getOperand(0))) {
+ if (isInertARCValue(Inst->getOperand(0), VisitedPhis)) {
if (!Inst->getType()->isVoidTy())
Inst->replaceAllUsesWith(Inst->getOperand(0));
Inst->eraseFromParent();
diff --git a/llvm/test/Transforms/ObjCARC/inert-global.ll b/llvm/test/Transforms/ObjCARC/inert-global.ll
index c23d2f98b949..464d78b715e5 100644
--- a/llvm/test/Transforms/ObjCARC/inert-global.ll
+++ b/llvm/test/Transforms/ObjCARC/inert-global.ll
@@ -8,6 +8,7 @@
@.str = private unnamed_addr constant [4 x i8] c"abc\00", section "__TEXT,__cstring,cstring_literals", align 1
@.str1 = private unnamed_addr constant [4 x i8] c"def\00", section "__TEXT,__cstring,cstring_literals", align 1
@_unnamed_cfstring_ = private global %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i32 0, i32 0), i64 3 }, section "__DATA,__cfstring", align 8 #0
+ at _unnamed_cfstring_.1 = private global %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i32 0, i32 0), i64 3 }, section "__DATA,__cfstring", align 8 #0
@_unnamed_cfstring_wo_attr = private global %struct.__NSConstantString_tag { i32* getelementptr inbounds ([0 x i32], [0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str1, i32 0, i32 0), i64 3 }, section "__DATA,__cfstring", align 8
@_NSConcreteGlobalBlock = external global i8*
@.str.1 = private unnamed_addr constant [6 x i8] c"v8@?0\00", align 1
@@ -87,6 +88,40 @@ return:
ret %0* %phi2
}
+; CHECK-LABEL: define void @test_conditional1(
+; CHECK-NOT: @llvm.objc
+; CHECK: ret void
+
+define void @test_conditional1(i32 %i) {
+entry:
+ %v0 = add nsw i32 %i, -1
+ %c1 = icmp eq i32 %v0, 0
+ br i1 %c1, label %while.end, label %while.body
+
+while.body:
+ %v1 = phi i32 [ %v5, %if.end ], [ %v0, %entry ]
+ %v2 = phi i8* [ %v4, %if.end ], [ bitcast (%struct.__NSConstantString_tag* @_unnamed_cfstring_.1 to i8*), %entry ]
+ %v3 = tail call i8* @llvm.objc.retain(i8* %v2)
+ %cmp = icmp eq i32 %v1, 2
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+ call void @llvm.objc.release(i8* %v2)
+ br label %if.end
+
+if.end:
+ %v4 = phi i8* [ bitcast (%struct.__NSConstantString_tag* @_unnamed_cfstring_ to i8*), %if.then ], [ %v2, %while.body ]
+ call void @llvm.objc.release(i8* %v2)
+ %v5 = add nsw i32 %v1, -1
+ %tobool = icmp eq i32 %v5, 0
+ br i1 %tobool, label %while.end, label %while.body
+
+while.end:
+ %v6 = phi i8* [ null, %entry ], [ %v4, %if.end ]
+ call void @llvm.objc.release(i8* %v6)
+ ret void
+}
+
declare void @foo()
declare i8* @llvm.objc.retain(i8*) local_unnamed_addr
More information about the llvm-commits
mailing list