[PATCH] D103440: [WIP][analyzer] Introduce range-based reasoning for addition operator

Manas Gupta via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Jun 3 19:30:34 PDT 2021


manas updated this revision to Diff 349749.
manas added a comment.

Added tests for residual paths and negation of certain values, and fixed expected warnings for UNKNOWN cases.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D103440/new/

https://reviews.llvm.org/D103440

Files:
  clang/test/Analysis/constant-folding.c


Index: clang/test/Analysis/constant-folding.c
===================================================================
--- clang/test/Analysis/constant-folding.c
+++ clang/test/Analysis/constant-folding.c
@@ -251,3 +251,71 @@
     clang_analyzer_eval((b % a) < x + 10); // expected-warning{{TRUE}}
   }
 }
+
+void testAdditionRules(unsigned int a, unsigned int b, int c, int d) {
+  if (a == 0) {
+    clang_analyzer_eval((a + 0) == 0); // expected-warning{{TRUE}}
+  }
+
+  // Checks for unsigned operands
+  clang_analyzer_eval((a + b) < 0); // expected-warning{{FALSE}}
+  clang_analyzer_eval((a + b) <= UINT_MAX); // expected-warning{{TRUE}}
+
+  if (a == UINT_MAX && b == UINT_MAX) {
+    clang_analyzer_eval((a + b) == UINT_MAX - 1); // expected-warning{{TRUE}}
+  }
+
+  // Checks for inclusive ranges for unsigned integers
+  if (a >= 0 && a <= 10 && b >= 0 && b <= 20) {
+    clang_analyzer_eval((a + b) >= 0); // expected-warning{{TRUE}}
+    clang_analyzer_eval((a + b) > 30); // expected-warning{{FALSE}}
+  }
+
+  // Checks for negative signed integers
+  if (c < 0 && d < 0) {
+    clang_analyzer_eval((c + d) < 0); // expected-warning{{UNKNOWN}}
+
+    if (c != INT_MIN) {
+      clang_analyzer_eval((c + d) == -1); // expected-warning{{FALSE}}
+      clang_analyzer_eval((c + d) == 0); // expected-warning{{FALSE}}
+      clang_analyzer_eval((c + d) <= -2); // expected-warning{{UNKNOWN}}
+      clang_analyzer_eval((c + d) >= 1); // expected-warning{{UNKNOWN}}
+    }
+
+    if (c == INT_MIN && d == INT_MIN) {
+      clang_analyzer_eval((c + d) == 0); // expected-warning{{TRUE}}
+    }
+
+    if (c == INT_MIN && d != INT_MIN) {
+      clang_analyzer_eval((c + d) > 0); // expected-warning{{TRUE}}
+    }
+
+    if (c >= -20 && d >= -40) {
+      clang_analyzer_eval((c + d) < -1); // expected-warning{{TRUE}}
+      clang_analyzer_eval((c + d) >= -60); // expected-warning{{TRUE}}
+    }
+  }
+
+  // Checks for integers with different sign bits
+  if (c < 0 && d > 0) {
+    if (c >= -20 && d <= 10) {
+      clang_analyzer_eval((c + d) > -20); // expected-warning{{TRUE}}
+      clang_analyzer_eval((c + d) < 10); // expected-warning{{TRUE}}
+    }
+  }
+
+  // Checks for overlapping signed integers ranges
+  if (c >= -20 && c <= 20 && d >= -10 && d <= 10) {
+    clang_analyzer_eval((c + d) >= -30); // expected-warning{{TRUE}}
+    clang_analyzer_eval((c + d) <= 30); // expected-warning{{TRUE}}
+  }
+
+  // Checks for positive signed integers
+  if (c > 0 && d > 0) {
+    clang_analyzer_eval((c + d) == 1); // expected-warning{{FALSE}}
+    clang_analyzer_eval((c + d) == 0); // expected-warning{{FALSE}}
+    clang_analyzer_eval((c + d) == -1); // expected-warning{{FALSE}}
+    clang_analyzer_eval((c + d) > 1); // expected-warning{{UNKNOWN}}
+    clang_analyzer_eval((c + d) < -1); // expected-warning{{UNKNOWN}}
+  }
+}


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