analyzer: fix ICE on strlen ((char *)&VECTOR_CST) [PR111361]

gcc/analyzer/ChangeLog:
	PR analyzer/111361
	* region-model.cc (svalue_byte_range_has_null_terminator_1): The
	initial byte of an all-zeroes SVAL is a zero byte.  Remove
	gcc_unreachable from SK_CONSTANT for constants that aren't
	STRING_CST or INTEGER_CST.

gcc/testsuite/ChangeLog:
	PR analyzer/111361
	* c-c++-common/analyzer/strlen-pr111361.c: New test.
	* c-c++-common/analyzer/strncpy-1.c (test_zero_fill): Remove fixed
	xfail.
	* c-c++-common/analyzer/strncpy-pr111361.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

4 files changed, 35 insertions, 3 deletions

diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index f01010c..dbb2149 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -3605,6 +3605,14 @@ svalue_byte_range_has_null_terminator_1 (const svalue *sval,
 					 byte_offset_t *out_bytes_read,
 					 logger *logger)
 {
+  if (bytes.m_start_byte_offset == 0
+      && sval->all_zeroes_p ())
+    {
+      /* The initial byte of an all-zeroes SVAL is a zero byte.  */
+      *out_bytes_read = 1;
+      return tristate (true);
+    }
+
   switch (sval->get_kind ())
     {
     case SK_CONSTANT:
@@ -3631,7 +3639,6 @@ svalue_byte_range_has_null_terminator_1 (const svalue *sval,
 	    return tristate::TS_UNKNOWN;
 
 	  default:
-	    gcc_unreachable ();
 	    break;
 	  }
       }
diff --git a/gcc/testsuite/c-c++-common/analyzer/strlen-pr111361.c b/gcc/testsuite/c-c++-common/analyzer/strlen-pr111361.c
new file mode 100644
index 0000000..b3b875c
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/strlen-pr111361.c
@@ -0,0 +1,18 @@
+#include "analyzer-decls.h"
+
+typedef int __attribute__((__vector_size__ (32))) V;
+
+typedef __SIZE_TYPE__ size_t;
+
+static size_t __attribute__((noinline))
+call_strlen (const char *p)
+{
+  return __builtin_strlen (p);
+}
+
+void
+foo (void *out)
+{
+  V v = (V) { };
+  __analyzer_eval (call_strlen ((const char *)&v) == 0); /* { dg-warning "TRUE" } */
+}
diff --git a/gcc/testsuite/c-c++-common/analyzer/strncpy-1.c b/gcc/testsuite/c-c++-common/analyzer/strncpy-1.c
index 3ca1d81..8edaf26 100644
--- a/gcc/testsuite/c-c++-common/analyzer/strncpy-1.c
+++ b/gcc/testsuite/c-c++-common/analyzer/strncpy-1.c
@@ -44,8 +44,7 @@ test_zero_fill (char *dst)
   __analyzer_eval (dst[4] == '\0'); /* { dg-warning "TRUE" "correct" { xfail *-*-* } } */
   /* { dg-bogus "UNKNOWN" "status quo" { xfail *-*-* } .-1 } */
   __analyzer_eval (__analyzer_get_strlen (dst) == 0); /* { dg-warning "TRUE" } */
-  __analyzer_eval (__analyzer_get_strlen (dst + 1) == 0); /* { dg-warning "TRUE" "correct" { xfail *-*-* } } */
-  /* { dg-bogus "UNKNOWN" "status quo" { xfail *-*-* } .-1 } */
+  __analyzer_eval (__analyzer_get_strlen (dst + 1) == 0); /* { dg-warning "TRUE" } */
 }
 
 char *test_unterminated_concrete_a (char *dst)
diff --git a/gcc/testsuite/c-c++-common/analyzer/strncpy-pr111361.c b/gcc/testsuite/c-c++-common/analyzer/strncpy-pr111361.c
new file mode 100644
index 0000000..da3eaeb
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/analyzer/strncpy-pr111361.c
@@ -0,0 +1,8 @@
+typedef int __attribute__((__vector_size__ (32))) V;
+
+void
+foo (char *out)
+{
+  V v = (V) { };
+  __builtin_strncpy (out, (char *)&v, 5);
+}