Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
Pushed to trunk as r16-6136-gc48970fc4a4d17.
gcc/analyzer/ChangeLog:
PR analyzer/122975
* region-model-manager.cc (region_model_manager::maybe_fold_binop): Fold
X + (-X) to zero.
gcc/testsuite/ChangeLog:
PR analyzer/122975
* c-c++-common/analyzer/arith-1.c: New test.
* c-c++-common/analyzer/infinite-recursion-pr122975.c: New test.
Signed-off-by: David Malcolm <[email protected]>
---
gcc/analyzer/region-model-manager.cc | 5 +++++
gcc/testsuite/c-c++-common/analyzer/arith-1.c | 13 +++++++++++++
.../analyzer/infinite-recursion-pr122975.c | 5 +++++
3 files changed, 23 insertions(+)
create mode 100644 gcc/testsuite/c-c++-common/analyzer/arith-1.c
create mode 100644
gcc/testsuite/c-c++-common/analyzer/infinite-recursion-pr122975.c
diff --git a/gcc/analyzer/region-model-manager.cc
b/gcc/analyzer/region-model-manager.cc
index 2a6d047f4ce74..0b28b767a55e5 100644
--- a/gcc/analyzer/region-model-manager.cc
+++ b/gcc/analyzer/region-model-manager.cc
@@ -680,6 +680,11 @@ region_model_manager::maybe_fold_binop (tree type, enum
tree_code op,
/* (VAL + 0) -> VAL. */
if (cst1 && zerop (cst1))
return get_or_create_cast (type, arg0);
+ /* X + (-X) -> 0. */
+ if (const unaryop_svalue *unary_op = arg1->dyn_cast_unaryop_svalue ())
+ if (unary_op->get_op () == NEGATE_EXPR
+ && unary_op->get_arg () == arg0)
+ return get_or_create_int_cst (type, 0);
break;
case MINUS_EXPR:
/* (VAL - 0) -> VAL. */
diff --git a/gcc/testsuite/c-c++-common/analyzer/arith-1.c
b/gcc/testsuite/c-c++-common/analyzer/arith-1.c
new file mode 100644
index 0000000000000..af58466c7bc77
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/arith-1.c
@@ -0,0 +1,13 @@
+#include "analyzer-decls.h"
+
+static int __attribute__((noipa))
+negate_int (int x)
+{
+ return -x;
+}
+
+void
+test_1 (int a)
+{
+ __analyzer_eval (a + negate_int (a) == 0); /* { dg-warning "TRUE" } */
+}
diff --git a/gcc/testsuite/c-c++-common/analyzer/infinite-recursion-pr122975.c
b/gcc/testsuite/c-c++-common/analyzer/infinite-recursion-pr122975.c
new file mode 100644
index 0000000000000..c241f4169f7fb
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/infinite-recursion-pr122975.c
@@ -0,0 +1,5 @@
+void fun(int x, int y)
+{
+ if (x + y != 0)
+ fun(x, -x); /* { dg-bogus "infinite recursion" } */
+}
--
2.26.3
