This patch fixes a bug where maybe_fold_sub_svalue did not fold the access of a single char from a string to a char when the offset was zero because get_relative_concrete_offset did return false for cast_regions.
Regrtested on Linux x86_64. 2022-09-02 Tim Lange <m...@tim-lange.me> gcc/analyzer/ChangeLog: * region.cc (cast_region::get_relative_concrete_offset): New overloaded method. * region.h: Add cast_region::get_relative_concrete_offset. gcc/testsuite/ChangeLog: * gcc.dg/analyzer/fold-string-to-char.c: New test. --- gcc/analyzer/region.cc | 10 ++++++++++ gcc/analyzer/region.h | 2 ++ gcc/testsuite/gcc.dg/analyzer/fold-string-to-char.c | 8 ++++++++ 3 files changed, 20 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/analyzer/fold-string-to-char.c diff --git a/gcc/analyzer/region.cc b/gcc/analyzer/region.cc index f4aba6b9c88..9c8279b130d 100644 --- a/gcc/analyzer/region.cc +++ b/gcc/analyzer/region.cc @@ -1556,6 +1556,16 @@ cast_region::dump_to_pp (pretty_printer *pp, bool simple) const } } +/* Implementation of region::get_relative_concrete_offset vfunc + for cast_region. */ + +bool +cast_region::get_relative_concrete_offset (bit_offset_t *out) const +{ + *out = (int) 0; + return true; +} + /* class heap_allocated_region : public region. */ /* Implementation of region::dump_to_pp vfunc for heap_allocated_region. */ diff --git a/gcc/analyzer/region.h b/gcc/analyzer/region.h index d37584b7285..34ce1fa1714 100644 --- a/gcc/analyzer/region.h +++ b/gcc/analyzer/region.h @@ -1087,6 +1087,8 @@ public: void accept (visitor *v) const final override; void dump_to_pp (pretty_printer *pp, bool simple) const final override; + bool get_relative_concrete_offset (bit_offset_t *out) const final override; + const region *get_original_region () const { return m_original_region; } private: diff --git a/gcc/testsuite/gcc.dg/analyzer/fold-string-to-char.c b/gcc/testsuite/gcc.dg/analyzer/fold-string-to-char.c new file mode 100644 index 00000000000..46139216bba --- /dev/null +++ b/gcc/testsuite/gcc.dg/analyzer/fold-string-to-char.c @@ -0,0 +1,8 @@ +#include "analyzer-decls.h" + +void test_1 (void) +{ + char str[] = "Hello"; + char *ptr = str; + __analyzer_eval (ptr[0] == 'H'); /* { dg-warning "TRUE" } */ +} -- 2.37.2