[ObjC][CodeGen] Assume a for-in loop is in bounds and cannot overflow #94885
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@llvm/pr-subscribers-clang-codegen Author: AtariDreams (AtariDreams) ChangesWhen accessing data in the buffer, we know we won't overrun the buffer, so we know it is inbounds. In addition, we know that the addition to increase the index is also NUW because the buffer's end has to be unsigned-greater-than 0, which becomes untrue if the bounds ever has an unsigned wrap. Full diff: https://github.com/llvm/llvm-project/pull/94885.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 281b2d9795f6c..80a64d8e4cdd9 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -1952,7 +1952,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
Builder.CreateLoad(StateItemsPtr, "stateitems");
// Fetch the value at the current index from the buffer.
- llvm::Value *CurrentItemPtr = Builder.CreateGEP(
+ llvm::Value *CurrentItemPtr = Builder.CreateInBoundsGEP(
ObjCIdType, EnumStateItems, index, "currentitem.ptr");
llvm::Value *CurrentItem =
Builder.CreateAlignedLoad(ObjCIdType, CurrentItemPtr, getPointerAlign());
@@ -2028,7 +2028,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
// First we check in the local buffer.
llvm::Value *indexPlusOne =
- Builder.CreateAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
+ Builder.CreateNUWAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
// If we haven't overrun the buffer yet, we can continue.
// Set the branch weights based on the simplifying assumption that this is
diff --git a/clang/test/CodeGenObjC/arc-foreach.m b/clang/test/CodeGenObjC/arc-foreach.m
index 71edc5161303c..9f7b60aef7a1b 100644
--- a/clang/test/CodeGenObjC/arc-foreach.m
+++ b/clang/test/CodeGenObjC/arc-foreach.m
@@ -53,7 +53,7 @@ void test0(NSArray *array) {
// CHECK-LP64: [[T0:%.*]] = getelementptr inbounds [[STATE_T]], ptr [[STATE]], i32 0, i32 1
// CHECK-LP64-NEXT: [[T1:%.*]] = load ptr, ptr [[T0]]
-// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr ptr, ptr [[T1]], i64
+// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr inbounds ptr, ptr [[T1]], i64
// CHECK-LP64-NEXT: [[T3:%.*]] = load ptr, ptr [[T2]]
// CHECK-LP64-NEXT: store ptr [[T3]], ptr [[X]]
@@ -100,7 +100,7 @@ void test1(NSArray *array) {
// CHECK-LP64: [[T0:%.*]] = getelementptr inbounds [[STATE_T]], ptr [[STATE]], i32 0, i32 1
// CHECK-LP64-NEXT: [[T1:%.*]] = load ptr, ptr [[T0]]
-// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr ptr, ptr [[T1]], i64
+// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr inbounds ptr, ptr [[T1]], i64
// CHECK-LP64-NEXT: [[T3:%.*]] = load ptr, ptr [[T2]]
// CHECK-LP64-NEXT: call ptr @llvm.objc.initWeak(ptr [[X]], ptr [[T3]])
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@llvm/pr-subscribers-clang Author: AtariDreams (AtariDreams) ChangesWhen accessing data in the buffer, we know we won't overrun the buffer, so we know it is inbounds. In addition, we know that the addition to increase the index is also NUW because the buffer's end has to be unsigned-greater-than 0, which becomes untrue if the bounds ever has an unsigned wrap. Full diff: https://github.com/llvm/llvm-project/pull/94885.diff 2 Files Affected:
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 281b2d9795f6c..80a64d8e4cdd9 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -1952,7 +1952,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
Builder.CreateLoad(StateItemsPtr, "stateitems");
// Fetch the value at the current index from the buffer.
- llvm::Value *CurrentItemPtr = Builder.CreateGEP(
+ llvm::Value *CurrentItemPtr = Builder.CreateInBoundsGEP(
ObjCIdType, EnumStateItems, index, "currentitem.ptr");
llvm::Value *CurrentItem =
Builder.CreateAlignedLoad(ObjCIdType, CurrentItemPtr, getPointerAlign());
@@ -2028,7 +2028,7 @@ void CodeGenFunction::EmitObjCForCollectionStmt(const ObjCForCollectionStmt &S){
// First we check in the local buffer.
llvm::Value *indexPlusOne =
- Builder.CreateAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
+ Builder.CreateNUWAdd(index, llvm::ConstantInt::get(NSUIntegerTy, 1));
// If we haven't overrun the buffer yet, we can continue.
// Set the branch weights based on the simplifying assumption that this is
diff --git a/clang/test/CodeGenObjC/arc-foreach.m b/clang/test/CodeGenObjC/arc-foreach.m
index 71edc5161303c..9f7b60aef7a1b 100644
--- a/clang/test/CodeGenObjC/arc-foreach.m
+++ b/clang/test/CodeGenObjC/arc-foreach.m
@@ -53,7 +53,7 @@ void test0(NSArray *array) {
// CHECK-LP64: [[T0:%.*]] = getelementptr inbounds [[STATE_T]], ptr [[STATE]], i32 0, i32 1
// CHECK-LP64-NEXT: [[T1:%.*]] = load ptr, ptr [[T0]]
-// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr ptr, ptr [[T1]], i64
+// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr inbounds ptr, ptr [[T1]], i64
// CHECK-LP64-NEXT: [[T3:%.*]] = load ptr, ptr [[T2]]
// CHECK-LP64-NEXT: store ptr [[T3]], ptr [[X]]
@@ -100,7 +100,7 @@ void test1(NSArray *array) {
// CHECK-LP64: [[T0:%.*]] = getelementptr inbounds [[STATE_T]], ptr [[STATE]], i32 0, i32 1
// CHECK-LP64-NEXT: [[T1:%.*]] = load ptr, ptr [[T0]]
-// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr ptr, ptr [[T1]], i64
+// CHECK-LP64-NEXT: [[T2:%.*]] = getelementptr inbounds ptr, ptr [[T1]], i64
// CHECK-LP64-NEXT: [[T3:%.*]] = load ptr, ptr [[T2]]
// CHECK-LP64-NEXT: call ptr @llvm.objc.initWeak(ptr [[X]], ptr [[T3]])
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AZero13
changed the title
rjmccall
reviewed
Jun 10, 2024
davidchisnall
approved these changes
Jun 11, 2024
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@rjmccall do you think you could merge this? (I don't have commit perms) |
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I don't usually do that for people, sorry. |
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@JOE1994 Could you please merge this, as I do not have merge permissions? |
When accessing data in the buffer, we know we won't overrun the buffer, so we know it is inbounds. In addition, we know that the addition to increase the index is also NUW because the buffer's end has to be unsigned-greater-than 0, which becomes untrue if the bounds ever has an unsigned wrap.
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/59/builds/1385 Here is the relevant piece of the build log for the reference: |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/50/builds/971 Here is the relevant piece of the build log for the reference: |
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Those CI failures look unrelated. |
aaryanshukla
pushed a commit
to aaryanshukla/llvm-project
that referenced
this pull request
Jul 14, 2024
…llvm#94885) When accessing data in the buffer, we know we won't overrun the buffer, so we know it is inbounds. In addition, we know that the addition to increase the index is also NUW because the buffer's end has to be unsigned-greater-than 0, which becomes untrue if the bounds ever has an unsigned wrap.
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When accessing data in the buffer, we know we won't overrun the buffer, so we know it is inbounds. In addition, we know that the addition to increase the index is also NUW because the buffer's end has to be unsigned-greater-than 0, which becomes untrue if the bounds ever has an unsigned wrap.