tree-object-size.c (pass_through_call): Use gimple_call_return_flags ERF_RETURN*ARG* for builtins other than...

	* tree-object-size.c (pass_through_call): Use gimple_call_return_flags
	ERF_RETURN*ARG* for builtins other than BUILT_IN_ASSUME_ALIGNED,
	check for the latter with gimple_call_builtin_p.  Do not handle
	BUILT_IN_STPNCPY_CHK which is not a pass through call.

	* gcc.dg/builtin-object-size-18.c: New test.

From-SVN: r255133

4 files changed, 36 insertions, 27 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1cbc290..787e545 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-11-24  Jakub Jelinek  <jakub@redhat.com>
+
+	* tree-object-size.c (pass_through_call): Use gimple_call_return_flags
+	ERF_RETURN*ARG* for builtins other than BUILT_IN_ASSUME_ALIGNED,
+	check for the latter with gimple_call_builtin_p.  Do not handle
+	BUILT_IN_STPNCPY_CHK which is not a pass through call.
+
 2017-11-24  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	* config/arm/arm_neon.h: Fix pragma GCC push_options before
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 943f5fe..480a5c6 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2017-11-24  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/builtin-object-size-18.c: New test.
+
 2017-11-23  Julia Koval  <julia.koval@intel.com>
 
 	gcc.target/i386/avx512f-vpexpandb-1.c: New test.
diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-18.c b/gcc/testsuite/gcc.dg/builtin-object-size-18.c
new file mode 100644
index 0000000..e065393
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-18.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* __stpncpy_chk could return buf up to buf + 64, so
+   the minimum object size might be far smaller than 64.  */
+/* { dg-final { scan-tree-dump-not "return 64;" "optimized" } } */
+
+typedef __SIZE_TYPE__ size_t;
+
+size_t
+foo (const char *p, size_t s, size_t t)
+{
+  char buf[64];
+  char *q = __builtin___stpncpy_chk (buf, p, s, t);
+  return __builtin_object_size (q, 2);
+}
diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index d45f50d..14cb435 100644
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -464,34 +464,17 @@ alloc_object_size (const gcall *call, int object_size_type)
 static tree
 pass_through_call (const gcall *call)
 {
-  tree callee = gimple_call_fndecl (call);
+  unsigned rf = gimple_call_return_flags (call);
+  if (rf & ERF_RETURNS_ARG)
+    {
+      unsigned argnum = rf & ERF_RETURN_ARG_MASK;
+      if (argnum < gimple_call_num_args (call))
+	return gimple_call_arg (call, argnum);
+    }
 
-  if (callee
-      && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
-    switch (DECL_FUNCTION_CODE (callee))
-      {
-      case BUILT_IN_MEMCPY:
-      case BUILT_IN_MEMMOVE:
-      case BUILT_IN_MEMSET:
-      case BUILT_IN_STRCPY:
-      case BUILT_IN_STRNCPY:
-      case BUILT_IN_STRCAT:
-      case BUILT_IN_STRNCAT:
-      case BUILT_IN_MEMCPY_CHK:
-      case BUILT_IN_MEMMOVE_CHK:
-      case BUILT_IN_MEMSET_CHK:
-      case BUILT_IN_STRCPY_CHK:
-      case BUILT_IN_STRNCPY_CHK:
-      case BUILT_IN_STPNCPY_CHK:
-      case BUILT_IN_STRCAT_CHK:
-      case BUILT_IN_STRNCAT_CHK:
-      case BUILT_IN_ASSUME_ALIGNED:
-	if (gimple_call_num_args (call) >= 1)
-	  return gimple_call_arg (call, 0);
-	break;
-      default:
-	break;
-      }
+  /* __builtin_assume_aligned is intentionally not marked RET1.  */
+  if (gimple_call_builtin_p (call, BUILT_IN_ASSUME_ALIGNED))
+    return gimple_call_arg (call, 0);
 
   return NULL_TREE;
 }