C++: Infer 'b1 = true' and 'b2 = true' from 'b1 && b2 = true', and in…

…fer 'b1 = false' and 'b2 = false' from 'b1 || b2 = false'.
github · Jan 17, 2025 · 5c494c3 · 5c494c3
1 parent eadccf2
commit 5c494c3
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diff --git a/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll b/cpp/ql/lib/semmle/code/cpp/controlflow/IRGuards.qll
@@ -994,6 +994,18 @@ private module Cached {
     )
     or
     unary_compares_eq(test.(BuiltinExpectCallValueNumber).getCondition(), op, k, areEqual, value)
+    or
+    exists(BinaryLogicalOperation logical, Expr operand, boolean b |
+      test.getAnInstruction().getUnconvertedResultExpression() = logical and
+      op.getDef().getUnconvertedResultExpression() = operand and
+      logical.impliesValue(operand, b, value.(BooleanValue).getValue())
+    |
+      k = 1 and
+      areEqual = b
+      or
+      k = 0 and
+      areEqual = b.booleanNot()
+    )
   }
 
   /** Rearrange various simple comparisons into `left == right + k` form. */

diff --git a/cpp/ql/test/library-tests/controlflow/guards/GuardsCompare.expected b/cpp/ql/test/library-tests/controlflow/guards/GuardsCompare.expected
@@ -563,16 +563,20 @@
 | 182 | ... >= ... == 0 when ... >= ... is false |
 | 182 | ... >= ... == 1 when ... && ... is true |
 | 182 | ... >= ... == 1 when ... >= ... is true |
+| 182 | b1 != 0 when ! ... is false |
 | 182 | b1 != 0 when ... && ... is true |
 | 182 | b1 != 0 when b1 is true |
 | 182 | b1 != 1 when b1 is false |
 | 182 | b1 == 0 when b1 is false |
+| 182 | b1 == 1 when ! ... is false |
 | 182 | b1 == 1 when ... && ... is true |
 | 182 | b1 == 1 when b1 is true |
+| 182 | b2 != 0 when ! ... is false |
 | 182 | b2 != 0 when ... && ... is true |
 | 182 | b2 != 0 when b2 is true |
 | 182 | b2 != 1 when b2 is false |
 | 182 | b2 == 0 when b2 is false |
+| 182 | b2 == 1 when ! ... is false |
 | 182 | b2 == 1 when ... && ... is true |
 | 182 | b2 == 1 when b2 is true |
 | 182 | foo < 1.0+0 when ... && ... is true |
@@ -610,14 +614,18 @@
 | 193 | ... \|\| ... == 1 when ! ... is false |
 | 193 | ... \|\| ... == 1 when ... \|\| ... is true |
 | 193 | b1 != 0 when b1 is true |
+| 193 | b1 != 1 when ! ... is true |
 | 193 | b1 != 1 when ... \|\| ... is false |
 | 193 | b1 != 1 when b1 is false |
+| 193 | b1 == 0 when ! ... is true |
 | 193 | b1 == 0 when ... \|\| ... is false |
 | 193 | b1 == 0 when b1 is false |
 | 193 | b1 == 1 when b1 is true |
 | 193 | b2 != 0 when b2 is true |
+| 193 | b2 != 1 when ! ... is true |
 | 193 | b2 != 1 when ... \|\| ... is false |
 | 193 | b2 != 1 when b2 is false |
+| 193 | b2 == 0 when ! ... is true |
 | 193 | b2 == 0 when ... \|\| ... is false |
 | 193 | b2 == 0 when b2 is false |
 | 193 | b2 == 1 when b2 is true |

diff --git a/cpp/ql/test/library-tests/controlflow/guards/GuardsEnsure.expected b/cpp/ql/test/library-tests/controlflow/guards/GuardsEnsure.expected
@@ -640,10 +640,14 @@ unary
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:6:182:16 | ! ... | != | 1 | 185 | 188 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:6:182:16 | ! ... | == | 0 | 185 | 188 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:6:182:16 | ! ... | == | 1 | 182 | 184 |
+| test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:9 | b1 | != | 0 | 185 | 188 |
+| test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:9 | b1 | == | 1 | 185 | 188 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:15 | ... && ... | != | 0 | 185 | 188 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:15 | ... && ... | != | 1 | 182 | 184 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:15 | ... && ... | == | 0 | 182 | 184 |
 | test.cpp:182:6:182:16 | ! ... | test.cpp:182:8:182:15 | ... && ... | == | 1 | 185 | 188 |
+| test.cpp:182:6:182:16 | ! ... | test.cpp:182:14:182:15 | b2 | != | 0 | 185 | 188 |
+| test.cpp:182:6:182:16 | ! ... | test.cpp:182:14:182:15 | b2 | == | 1 | 185 | 188 |
 | test.cpp:182:8:182:9 | b1 | test.cpp:182:8:182:9 | b1 | != | 0 | 181 | 182 |
 | test.cpp:182:8:182:9 | b1 | test.cpp:182:8:182:9 | b1 | != | 0 | 182 | 182 |
 | test.cpp:182:8:182:9 | b1 | test.cpp:182:8:182:9 | b1 | == | 1 | 181 | 182 |
@@ -674,10 +678,14 @@ unary
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:6:193:16 | ! ... | != | 1 | 197 | 199 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:6:193:16 | ! ... | == | 0 | 197 | 199 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:6:193:16 | ! ... | == | 1 | 193 | 196 |
+| test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:9 | b1 | != | 1 | 193 | 196 |
+| test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:9 | b1 | == | 0 | 193 | 196 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:15 | ... \|\| ... | != | 0 | 197 | 199 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:15 | ... \|\| ... | != | 1 | 193 | 196 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:15 | ... \|\| ... | == | 0 | 193 | 196 |
 | test.cpp:193:6:193:16 | ! ... | test.cpp:193:8:193:15 | ... \|\| ... | == | 1 | 197 | 199 |
+| test.cpp:193:6:193:16 | ! ... | test.cpp:193:14:193:15 | b2 | != | 1 | 193 | 196 |
+| test.cpp:193:6:193:16 | ! ... | test.cpp:193:14:193:15 | b2 | == | 0 | 193 | 196 |
 | test.cpp:193:8:193:9 | b1 | test.cpp:193:8:193:9 | b1 | != | 1 | 192 | 193 |
 | test.cpp:193:8:193:9 | b1 | test.cpp:193:8:193:9 | b1 | != | 1 | 193 | 193 |
 | test.cpp:193:8:193:9 | b1 | test.cpp:193:8:193:9 | b1 | == | 0 | 192 | 193 |