llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-static-analyzer-1
Author: JOSTAR (shenjunjiekoda)
<details>
<summary>Changes</summary>
The current implementation of APInt extension in the code can trigger an
assertion failure when the `zext` function is called with a target width
smaller than the current bit width. For example:
```cpp
if (InitNum.getBitWidth() != BoundNum.getBitWidth()) {
InitNum = InitNum.zext(BoundNum.getBitWidth());
BoundNum = BoundNum.zext(InitNum.getBitWidth());
}
```
This logic does not guarantee that the `zext` target width is always greater
than or equal to the current bit width, leading to potential crashes.
Expected Behavior:
- Ensure InitNum and BoundNum are extended to the maximum of their respective
widths.
- Prevent assertion failures by enforcing correct `zext` usage.
Depend on ##<!-- -->121201
---
Full diff: https://github.com/llvm/llvm-project/pull/121203.diff
1 Files Affected:
- (modified) clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp (+6-4)
``````````diff
diff --git a/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
b/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
index 96f5d7c44baf89..e3b27e22712b58 100644
--- a/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
+++ b/clang/lib/StaticAnalyzer/Core/LoopUnrolling.cpp
@@ -283,10 +283,12 @@ static bool shouldCompletelyUnroll(const Stmt *LoopStmt,
ASTContext &ASTCtx,
llvm::APInt InitNum =
Matches[0].getNodeAs<IntegerLiteral>("initNum")->getValue();
auto CondOp = Matches[0].getNodeAs<BinaryOperator>("conditionOperator");
- if (InitNum.getBitWidth() != BoundNum.getBitWidth()) {
- InitNum = InitNum.zext(BoundNum.getBitWidth());
- BoundNum = BoundNum.zext(InitNum.getBitWidth());
- }
+ unsigned MaxWidth = std::max(InitNum.getBitWidth(), BoundNum.getBitWidth());
+
+ if (InitNum.getBitWidth() != MaxWidth)
+ InitNum = InitNum.zext(MaxWidth);
+ if (BoundNum.getBitWidth() != MaxWidth)
+ BoundNum = BoundNum.zext(MaxWidth);
if (CondOp->getOpcode() == BO_GE || CondOp->getOpcode() == BO_LE)
maxStep = (BoundNum - InitNum + 1).abs().getZExtValue();
``````````
</details>
https://github.com/llvm/llvm-project/pull/121203
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