diff --git a/llvm/include/llvm/Analysis/ValueTracking.h b/llvm/include/llvm/Analysis/ValueTracking.h
--- a/llvm/include/llvm/Analysis/ValueTracking.h
+++ b/llvm/include/llvm/Analysis/ValueTracking.h
@@ -413,10 +413,12 @@
bool getUnderlyingObjectsForCodeGen(const Value *V,
SmallVectorImpl<Value *> &Objects);
- /// Finds alloca where the value comes from.
- AllocaInst *findAllocaForValue(Value *V);
- inline const AllocaInst *findAllocaForValue(const Value *V) {
- return findAllocaForValue(const_cast<Value *>(V));
+ /// Returns unique alloca where the value comes from, or nullptr.
+ /// If OffsetZero is true check that V points to the begining of the alloca.
+ AllocaInst *findAllocaForValue(Value *V, bool OffsetZero = false);
+ inline const AllocaInst *findAllocaForValue(const Value *V,
+ bool OffsetZero = false) {
+ return findAllocaForValue(const_cast<Value *>(V), OffsetZero);
}
/// Return true if the only users of this pointer are lifetime markers.
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4331,7 +4331,8 @@
}
static AllocaInst *
-findAllocaForValue(Value *V, DenseMap<Value *, AllocaInst *> &AllocaForValue) {
+findAllocaForValue(Value *V, DenseMap<Value *, AllocaInst *> &AllocaForValue,
+ bool OffsetZero) {
if (AllocaInst *AI = dyn_cast<AllocaInst>(V))
return AI;
// See if we've already calculated (or started to calculate) alloca for a
@@ -4344,36 +4345,46 @@
AllocaForValue[V] = nullptr;
AllocaInst *Res = nullptr;
if (CastInst *CI = dyn_cast<CastInst>(V))
- Res = findAllocaForValue(CI->getOperand(0), AllocaForValue);
- else if (auto *SI = dyn_cast<SelectInst>(V)) {
- Res = findAllocaForValue(SI->getTrueValue(), AllocaForValue);
- if (!Res)
- return nullptr;
- AllocaInst *F = findAllocaForValue(SI->getFalseValue(), AllocaForValue);
- if (F != Res)
- return nullptr;
- } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ Res = findAllocaForValue(CI->getOperand(0), AllocaForValue, OffsetZero);
+ else if (PHINode *PN = dyn_cast<PHINode>(V)) {
for (Value *IncValue : PN->incoming_values()) {
// Allow self-referencing phi-nodes.
if (IncValue == PN)
continue;
- AllocaInst *IncValueAI = findAllocaForValue(IncValue, AllocaForValue);
+ AllocaInst *IncValueAI =
+ findAllocaForValue(IncValue, AllocaForValue, OffsetZero);
// AI for incoming values should exist and should all be equal.
if (IncValueAI == nullptr || (Res != nullptr && IncValueAI != Res))
return nullptr;
Res = IncValueAI;
}
- } else if (GetElementPtrInst *EP = dyn_cast<GetElementPtrInst>(V)) {
- Res = findAllocaForValue(EP->getPointerOperand(), AllocaForValue);
+ } else if (auto *SI = dyn_cast<SelectInst>(V)) {
+ Res = findAllocaForValue(SI->getTrueValue(), AllocaForValue, OffsetZero);
+ if (!Res)
+ return nullptr;
+ AllocaInst *F =
+ findAllocaForValue(SI->getFalseValue(), AllocaForValue, OffsetZero);
+ if (F != Res)
+ return nullptr;
+ } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) {
+ if (OffsetZero) {
+ for (unsigned i = 1; i < GEP->getNumOperands(); ++i) {
+ ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i));
+ if (!OpC || !OpC->isZero())
+ return nullptr;
+ }
+ }
+ Res = findAllocaForValue(GEP->getPointerOperand(), AllocaForValue,
+ OffsetZero);
}
if (Res)
AllocaForValue[V] = Res;
return Res;
}
-AllocaInst *llvm::findAllocaForValue(Value *V) {
+AllocaInst *llvm::findAllocaForValue(Value *V, bool OffsetZero) {
DenseMap<Value *, AllocaInst *> AllocaForValue;
- return ::findAllocaForValue(V, AllocaForValue);
+ return ::findAllocaForValue(V, AllocaForValue, OffsetZero);
}
static bool onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
--- a/llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -1433,28 +1433,38 @@
class FindAllocaForValueTest
: public ValueTrackingTest,
- public ::testing::WithParamInterface<std::pair<const char *, bool>> {
+ public ::testing::WithParamInterface<
+ std::pair<const char *, std::pair<bool, bool>>> {
protected:
};
-const std::pair<const char *, bool> FindAllocaForValueTests[] = {
- {R"(
+const std::pair<const char *, std::pair<bool, bool>> FindAllocaForValueTests[] =
+ {
+ {R"(
define void @test() {
%a = alloca i64
%r = bitcast i64* %a to i32*
ret void
})",
- true},
+ {true, true}},
- {R"(
+ {R"(
define void @test() {
%a = alloca i32
%r = getelementptr i32, i32* %a, i32 1
ret void
})",
- true},
+ {true, false}},
+
+ {R"(
+ define void @test() {
+ %a = alloca i32
+ %r = getelementptr i32, i32* %a, i32 0
+ ret void
+ })",
+ {true, true}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
entry:
%a = alloca i32
@@ -1467,26 +1477,26 @@
exit:
ret void
})",
- true},
+ {true, true}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
%a = alloca i32
%r = select i1 %cond, i32* %a, i32* %a
ret void
})",
- true},
+ {true, true}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
%a = alloca i32
%b = alloca i32
%r = select i1 %cond, i32* %a, i32* %b
ret void
})",
- false},
+ {false, false}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
entry:
%a = alloca i64
@@ -1501,9 +1511,9 @@
exit:
ret void
})",
- true},
+ {true, false}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
entry:
%a = alloca i64
@@ -1518,17 +1528,17 @@
exit:
ret void
})",
- false},
+ {false, false}},
- {R"(
+ {R"(
define void @test(i1 %cond, i64* %a) {
entry:
%r = bitcast i64* %a to i32*
ret void
})",
- false},
+ {false, false}},
- {R"(
+ {R"(
define void @test(i1 %cond) {
entry:
%a = alloca i32
@@ -1542,7 +1552,7 @@
exit:
ret void
})",
- false},
+ {false, false}},
};
TEST_P(FindAllocaForValueTest, findAllocaForValue) {
@@ -1550,7 +1560,15 @@
Function *F = M->getFunction("test");
Instruction *I = &findInstructionByName(F, "r");
const AllocaInst *AI = findAllocaForValue(I);
- EXPECT_EQ(!!AI, GetParam().second);
+ EXPECT_EQ(!!AI, GetParam().second.first);
+}
+
+TEST_P(FindAllocaForValueTest, findAllocaForValueZeroOffset) {
+ auto M = parseModule(GetParam().first);
+ Function *F = M->getFunction("test");
+ Instruction *I = &findInstructionByName(F, "r");
+ const AllocaInst *AI = findAllocaForValue(I, true);
+ EXPECT_EQ(!!AI, GetParam().second.second);
}
INSTANTIATE_TEST_CASE_P(FindAllocaForValueTest, FindAllocaForValueTest,