https://github.com/NagyDonat created
https://github.com/llvm/llvm-project/pull/78442
This commit adds a testcase which highlights the current incorrect behavior of
the CSA diagnostic generation: it produces a note which says "Assuming 'arg' is
>= 0" in a situation where this is not a fresh assumption because 'arg' is an
unsigned integer.
I also created ticket #78440 to track this bug.
>From d76fb380052b6de7e47f4d7499717c6df8b4af93 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Don=C3=A1t=20Nagy?= <donat.n...@ericsson.com>
Date: Wed, 17 Jan 2024 13:28:20 +0100
Subject: [PATCH] [analyzer] Demonstrate superfluous unsigned >= 0 assumption
This commit adds a testcase which highlights the current incorrect
behavior of the CSA diagnostic generation: it produces a note which says
"Assuming 'arg' is >= 0" in a situation where this is not a fresh
assumption because 'arg' is an unsigned integer.
---
clang/test/Analysis/assuming-unsigned-ge-0.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
create mode 100644 clang/test/Analysis/assuming-unsigned-ge-0.c
diff --git a/clang/test/Analysis/assuming-unsigned-ge-0.c
b/clang/test/Analysis/assuming-unsigned-ge-0.c
new file mode 100644
index 000000000000000..553e68cb96c6bd3
--- /dev/null
+++ b/clang/test/Analysis/assuming-unsigned-ge-0.c
@@ -0,0 +1,19 @@
+// RUN: %clang_analyze_cc1 -analyzer-output=text \
+// RUN: -analyzer-checker=core -verify %s
+
+int assuming_unsigned_ge_0(unsigned arg) {
+ // TODO This testcase demonstrates the current incorrect behavior of Clang
+ // Static Analyzer: here 'arg' is unsigned, so "arg >= 0" is not a fresh
+ // assumption, but it still appears in the diagnostics as if it's fresh:
+ // expected-note@+2 {{Assuming 'arg' is >= 0}}
+ // expected-note@+1 {{Taking false branch}}
+ if (arg < 0)
+ return 0;
+ // expected-note@+2 {{Assuming 'arg' is <= 0}}
+ // expected-note@+1 {{Taking false branch}}
+ if (arg > 0)
+ return 0;
+ // expected-note@+2 {{Division by zero}}
+ // expected-warning@+1 {{Division by zero}}
+ return 100 / arg;
+}
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