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-rw-r--r--llvm/include/llvm/Analysis/MemoryBuiltins.h10
-rw-r--r--llvm/lib/Analysis/MemoryBuiltins.cpp30
-rw-r--r--llvm/lib/CodeGen/CodeGenPrepare.cpp14
-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp15
-rw-r--r--llvm/lib/Transforms/InstCombine/InstructionCombining.cpp9
-rw-r--r--llvm/test/Transforms/CodeGenPrepare/builtin-condition.ll35
6 files changed, 84 insertions, 29 deletions
diff --git a/llvm/include/llvm/Analysis/MemoryBuiltins.h b/llvm/include/llvm/Analysis/MemoryBuiltins.h
index 140b731c59d..b58f07e6947 100644
--- a/llvm/include/llvm/Analysis/MemoryBuiltins.h
+++ b/llvm/include/llvm/Analysis/MemoryBuiltins.h
@@ -141,6 +141,16 @@ bool getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
const TargetLibraryInfo *TLI, bool RoundToAlign = false,
ObjSizeMode Mode = ObjSizeMode::Exact);
+/// Try to turn a call to @llvm.objectsize into an integer value of the given
+/// Type. Returns null on failure.
+/// If MustSucceed is true, this function will not return null, and may return
+/// conservative values governed by the second argument of the call to
+/// objectsize.
+ConstantInt *lowerObjectSizeCall(IntrinsicInst *ObjectSize,
+ const DataLayout &DL,
+ const TargetLibraryInfo *TLI,
+ bool MustSucceed);
+
typedef std::pair<APInt, APInt> SizeOffsetType;
/// \brief Evaluate the size and offset of an object pointed to by a Value*
diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 0f4bfb8e2fb..eaac506dec4 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -388,6 +388,36 @@ bool llvm::getObjectSize(const Value *Ptr, uint64_t &Size, const DataLayout &DL,
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 1e5d682a331..3dea9eb6b1f 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -1948,18 +1948,8 @@ bool CodeGenPrepare::optimizeCallInst(CallInst *CI, bool& ModifiedDT) {
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 4d432d56aa3..eb5c63433e7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1440,17 +1440,12 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
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 0d29c1dceea..9a52874c4c2 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2027,12 +2027,9 @@ Instruction *InstCombiner::visitAllocSite(Instruction &MI) {
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.
}
diff --git a/llvm/test/Transforms/CodeGenPrepare/builtin-condition.ll b/llvm/test/Transforms/CodeGenPrepare/builtin-condition.ll
index e18d1b0fc0e..0d41e9e1edd 100644
--- a/llvm/test/Transforms/CodeGenPrepare/builtin-condition.ll
+++ b/llvm/test/Transforms/CodeGenPrepare/builtin-condition.ll
@@ -1,5 +1,38 @@
; RUN: opt -codegenprepare -S < %s | FileCheck %s
+; Ensure we act sanely on overflow.
+; CHECK-LABEL: define i32 @bar
+define i32 @bar() {
+entry:
+ ; CHECK: ret i32 -1
+ %az = alloca [2147483649 x i32], align 16
+ %a = alloca i8*, align 8
+ %arraydecay = getelementptr inbounds [2147483649 x i32], [2147483649 x i32]* %az, i32 0, i32 0
+ %0 = bitcast i32* %arraydecay to i8*
+ store i8* %0, i8** %a, align 8
+ %1 = load i8*, i8** %a, align 8
+ %2 = call i32 @llvm.objectsize.i32.p0i8(i8* %1, i1 false)
+ ret i32 %2
+}
+
+; CHECK-LABEL: define i32 @baz
+define i32 @baz(i32 %n) {
+entry:
+ ; CHECK: ret i32 -1
+ %az = alloca [1 x i32], align 16
+ %bz = alloca [4294967297 x i32], align 16
+ %tobool = icmp ne i32 %n, 0
+ %arraydecay = getelementptr inbounds [1 x i32], [1 x i32]* %az, i64 0, i64 0
+ %arraydecay1 = getelementptr inbounds [4294967297 x i32], [4294967297 x i32]* %bz, i64 0, i64 0
+ %cond = select i1 %tobool, i32* %arraydecay, i32* %arraydecay1
+ %0 = bitcast i32* %cond to i8*
+ %1 = call i32 @llvm.objectsize.i32.p0i8(i8* %0, i1 false)
+ ret i32 %1
+}
+
+declare i32 @llvm.objectsize.i32.p0i8(i8*, i1)
+
+; The following tests were generated by:
; #include<stdlib.h>
; #define STATIC_BUF_SIZE 10
; #define LARGER_BUF_SIZE 30
@@ -87,4 +120,4 @@ entry:
ret void
}
-declare i32 @printf(i8* nocapture readonly, ...) \ No newline at end of file
+declare i32 @printf(i8* nocapture readonly, ...)
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