[Analysis] Centralize objectsize lowering logic.
We're currently doing nearly the same thing for @llvm.objectsize in
three different places: two of them are missing checks for overflow,
and one of them could subtly break if InstCombine gets much smarter
about removing alloc sites. Seems like a good idea to not do that.
llvm-svn: 290214
diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 0f4bfb8..eaac506 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -388,6 +388,36 @@
return true;
}
+ConstantInt *llvm::lowerObjectSizeCall(IntrinsicInst *ObjectSize,
+ const DataLayout &DL,
+ const TargetLibraryInfo *TLI,
+ bool MustSucceed) {
+ assert(ObjectSize->getIntrinsicID() == Intrinsic::objectsize &&
+ "ObjectSize must be a call to llvm.objectsize!");
+
+ bool MaxVal = cast<ConstantInt>(ObjectSize->getArgOperand(1))->isZero();
+ ObjSizeMode Mode;
+ // Unless we have to fold this to something, try to be as accurate as
+ // possible.
+ if (MustSucceed)
+ Mode = MaxVal ? ObjSizeMode::Max : ObjSizeMode::Min;
+ else
+ Mode = ObjSizeMode::Exact;
+
+ // FIXME: Does it make sense to just return a failure value if the size won't
+ // fit in the output and `!MustSucceed`?
+ uint64_t Size;
+ auto *ResultType = cast<IntegerType>(ObjectSize->getType());
+ if (getObjectSize(ObjectSize->getArgOperand(0), Size, DL, TLI, false, Mode) &&
+ isUIntN(ResultType->getBitWidth(), Size))
+ return ConstantInt::get(ResultType, Size);
+
+ if (!MustSucceed)
+ return nullptr;
+
+ return ConstantInt::get(ResultType, MaxVal ? -1ULL : 0);
+}
+
STATISTIC(ObjectVisitorArgument,
"Number of arguments with unsolved size and offset");
STATISTIC(ObjectVisitorLoad,
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 1e5d682..3dea9eb 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1948,18 +1948,8 @@
default: break;
case Intrinsic::objectsize: {
// Lower all uses of llvm.objectsize.*
- uint64_t Size;
- Type *ReturnTy = CI->getType();
- Constant *RetVal = nullptr;
- ConstantInt *Op1 = cast<ConstantInt>(II->getArgOperand(1));
- ObjSizeMode Mode = Op1->isZero() ? ObjSizeMode::Max : ObjSizeMode::Min;
- if (getObjectSize(II->getArgOperand(0),
- Size, *DL, TLInfo, false, Mode)) {
- RetVal = ConstantInt::get(ReturnTy, Size);
- } else {
- RetVal = ConstantInt::get(ReturnTy,
- Mode == ObjSizeMode::Min ? 0 : -1ULL);
- }
+ ConstantInt *RetVal =
+ lowerObjectSizeCall(II, *DL, TLInfo, /*MustSucceed=*/true);
// Substituting this can cause recursive simplifications, which can
// invalidate our iterator. Use a WeakVH to hold onto it in case this
// happens.
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 4d432d5..eb5c634 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1440,17 +1440,12 @@
switch (II->getIntrinsicID()) {
default: break;
- case Intrinsic::objectsize: {
- uint64_t Size;
- if (getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
- APInt APSize(II->getType()->getIntegerBitWidth(), Size);
- // Equality check to be sure that `Size` can fit in a value of type
- // `II->getType()`
- if (APSize == Size)
- return replaceInstUsesWith(CI, ConstantInt::get(II->getType(), APSize));
- }
+ case Intrinsic::objectsize:
+ if (ConstantInt *N =
+ lowerObjectSizeCall(II, DL, &TLI, /*MustSucceed=*/false))
+ return replaceInstUsesWith(CI, N);
return nullptr;
- }
+
case Intrinsic::bswap: {
Value *IIOperand = II->getArgOperand(0);
Value *X = nullptr;
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 0d29c1d..9a52874c 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2027,12 +2027,9 @@
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
if (II->getIntrinsicID() == Intrinsic::objectsize) {
- uint64_t Size;
- if (!getObjectSize(II->getArgOperand(0), Size, DL, &TLI)) {
- ConstantInt *CI = cast<ConstantInt>(II->getArgOperand(1));
- Size = CI->isZero() ? -1ULL : 0;
- }
- replaceInstUsesWith(*I, ConstantInt::get(I->getType(), Size));
+ ConstantInt *Result = lowerObjectSizeCall(II, DL, &TLI,
+ /*MustSucceed=*/true);
+ replaceInstUsesWith(*I, Result);
eraseInstFromFunction(*I);
Users[i] = nullptr; // Skip examining in the next loop.
}