re PR c/87028 (false positive -Wstringop-truncation strncpy with global variable source string)

	PR c/87028
	* calls.c (get_attr_nonstring_decl): Avoid setting *REF to
	SSA_NAME_VAR.
	* gcc/gimple-low.c (lower_stmt): Fold builtin calls here.
	* gimplify (maybe_fold_stmt): Avoid folding builtin calls.

	PR c/87028
	* c-c++-common/Wstringop-truncation.c: Remove xfails.
	* gcc.dg/Wstringop-truncation-5.c: New test.
	* gcc.dg/strcmpopt_1.c: Adjust.
	* gcc.dg/tree-ssa/pr79697.c: Same.

From-SVN: r266833

6 files changed, 147 insertions, 12 deletions

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 77dbe74..8bed4b4 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2018-12-05  Martin Sebor  <msebor@redhat.com>
+
+	PR c/87028
+	* c-c++-common/Wstringop-truncation.c: Remove xfails.
+	* gcc.dg/Wstringop-truncation-5.c: New test.
+	* gcc.dg/strcmpopt_1.c: Adjust.
+	* gcc.dg/tree-ssa/pr79697.c: Same.
+
 2018-12-05  Richard Sandiford  <richard.sandiford@arm.com>
 
 	PR tree-optimization/88064
diff --git a/gcc/testsuite/c-c++-common/Wstringop-truncation.c b/gcc/testsuite/c-c++-common/Wstringop-truncation.c
index e78e85e..b85711d 100644
--- a/gcc/testsuite/c-c++-common/Wstringop-truncation.c
+++ b/gcc/testsuite/c-c++-common/Wstringop-truncation.c
@@ -329,9 +329,8 @@ void test_strncpy_array (Dest *pd, int i, const char* s)
      of the array to NUL is not diagnosed.  */
   {
     /* This might be better written using memcpy() but it's safe so
-       it probably shouldn't be diagnosed.  It currently triggers
-       a warning because of bug 81704.  */
-    strncpy (dst7, "0123456", sizeof dst7);   /* { dg-bogus "\\\[-Wstringop-truncation]" "bug 81704" { xfail *-*-* } } */
+       it shouldn't be diagnosed.  */
+    strncpy (dst7, "0123456", sizeof dst7);   /* { dg-bogus "\\\[-Wstringop-truncation]" } */
     dst7[sizeof dst7 - 1] = '\0';
     sink (dst7);
   }
@@ -350,7 +349,7 @@ void test_strncpy_array (Dest *pd, int i, const char* s)
   }
 
   {
-    strncpy (pd->a5, "01234", sizeof pd->a5);   /* { dg-bogus "\\\[-Wstringop-truncation]" "bug 81704" { xfail *-*-* } } */
+    strncpy (pd->a5, "01234", sizeof pd->a5);   /* { dg-bogus "\\\[-Wstringop-truncation]" } */
     pd->a5[sizeof pd->a5 - 1] = '\0';
     sink (pd);
   }
diff --git a/gcc/testsuite/gcc.dg/Wstringop-truncation-5.c b/gcc/testsuite/gcc.dg/Wstringop-truncation-5.c
new file mode 100644
index 0000000..dbb5e1f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wstringop-truncation-5.c
@@ -0,0 +1,128 @@
+/* PR tree-optimization/87028 - false positive -Wstringop-truncation
+   strncpy with global variable source string
+   { dg-do compile }
+   { dg-options "-O2 -Wstringop-truncation" } */
+
+char *strncpy (char *, const char *, __SIZE_TYPE__);
+
+#define STR   "1234567890"
+
+struct S
+{
+  char a[5], b[5];
+};
+
+const char arr[] = STR;
+const char* const ptr = STR;
+
+const char arr2[][10] = { "123", STR };
+
+void test_literal (struct S *s)
+{
+  strncpy (s->a, STR, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a[sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr (struct S *s)
+{
+  strncpy (s->a, arr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr2 (struct S *s)
+{
+  strncpy (s->a, arr2[1], sizeof s->a - 1); /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+
+  strncpy (s->b, arr2[0], sizeof s->a - 1);
+}
+
+void test_global_ptr (struct S *s)
+{
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_arr (struct S *s)
+{
+  const char arr[] = STR;
+  strncpy (s->a, arr, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_ptr (struct S *s)
+{
+  const char* const ptr = STR;
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_compound_literal (struct S *s)
+{
+  strncpy (s->a, (char[]){ STR }, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}
+/* PR tree-optimization/87028 - false positive -Wstringop-truncation
+   strncpy with global variable source string
+   { dg-do compile }
+   { dg-options "-O2 -Wstringop-truncation" } */
+
+char *strncpy (char *, const char *, __SIZE_TYPE__);
+
+#define STR   "1234567890"
+
+struct S
+{
+  char a[5], b[5];
+};
+
+const char arr[] = STR;
+const char* const ptr = STR;
+
+const char arr2[][10] = { "123", STR };
+
+void test_literal (struct S *s)
+{
+  strncpy (s->a, STR, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a[sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr (struct S *s)
+{
+  strncpy (s->a, arr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_global_arr2 (struct S *s)
+{
+  strncpy (s->a, arr2[1], sizeof s->a - 1); /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+
+  strncpy (s->b, arr2[0], sizeof s->a - 1);
+}
+
+void test_global_ptr (struct S *s)
+{
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_arr (struct S *s)
+{
+  const char arr[] = STR;
+  strncpy (s->a, arr, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_local_ptr (struct S *s)
+{
+  const char* const ptr = STR;
+  strncpy (s->a, ptr, sizeof s->a - 1);     /* { dg-bogus "\\\[-Wstringop-truncation]" } */
+  s->a [sizeof s->a - 1] = '\0';
+}
+
+void test_compound_literal (struct S *s)
+{
+  strncpy (s->a, (char[]){ STR }, sizeof s->a - 1);
+  s->a [sizeof s->a - 1] = '\0';
+}
diff --git a/gcc/testsuite/gcc.dg/fold-bcopy.c b/gcc/testsuite/gcc.dg/fold-bcopy.c
index ed6cd06..9a54484 100644
--- a/gcc/testsuite/gcc.dg/fold-bcopy.c
+++ b/gcc/testsuite/gcc.dg/fold-bcopy.c
@@ -1,6 +1,6 @@
 /* PR tree-optimization/80933 - redundant bzero/bcopy calls not eliminated
    { dg-do compile }
-   { dg-options "-O0 -Wall -fdump-tree-gimple" } */
+   { dg-options "-O1 -Wall -fdump-tree-lower" } */
 
 void f0 (void *dst, const void *src, unsigned n)
 {
@@ -46,9 +46,9 @@ void f6 (void *p)
 /* Verify that calls to bcmp, bcopy, and bzero have all been removed
    and one of each replaced with memcmp, memmove, and memset, respectively.
    The remaining three should be eliminated.
-  { dg-final { scan-tree-dump-not "bcmp|bcopy|bzero" "gimple" } }
-  { dg-final { scan-tree-dump-times "memcmp|memmove|memset" 3 "gimple" } }
+  { dg-final { scan-tree-dump-not "bcmp|bcopy|bzero" "lower" } }
+  { dg-final { scan-tree-dump-times "memcmp|memmove|memset" 3 "lower" } }
 
   Verify that the bcopy to memmove transformation correctly transposed
   the source and destination pointer arguments.
-  { dg-final { scan-tree-dump-times "memmove \\(dst, src" 1 "gimple" } }  */
+  { dg-final { scan-tree-dump-times "memmove \\(dst, src" 1 "lower" } }  */
diff --git a/gcc/testsuite/gcc.dg/strcmpopt_1.c b/gcc/testsuite/gcc.dg/strcmpopt_1.c
index 40596a2..b1e0bc3 100644
--- a/gcc/testsuite/gcc.dg/strcmpopt_1.c
+++ b/gcc/testsuite/gcc.dg/strcmpopt_1.c
@@ -1,5 +1,5 @@
 /* { dg-do run } */
-/* { dg-options "-fdump-tree-gimple" } */
+/* { dg-options "-fdump-tree-lower" } */
 
 #include <string.h>
 #include <stdlib.h>
@@ -25,4 +25,4 @@ int main ()
   return 0;
 }
 
-/* { dg-final { scan-tree-dump-times "strcmp \\(" 2 "gimple" } } */
+/* { dg-final { scan-tree-dump-times "strcmp \\(" 2 "lower" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr79697.c b/gcc/testsuite/gcc.dg/tree-ssa/pr79697.c
index fc3580e..973ec0d 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr79697.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr79697.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-gimple -fdump-tree-cddce-details -fdump-tree-optimized" } */
+/* { dg-options "-O2 -fdump-tree-lower -fdump-tree-cddce-details -fdump-tree-optimized" } */
 
 void f(void)
 {
@@ -18,4 +18,4 @@ void h(void)
 
 /* { dg-final { scan-tree-dump "Deleting : __builtin_strdup" "cddce1" } } */
 /* { dg-final { scan-tree-dump "Deleting : __builtin_strndup" "cddce1" } } */
-/* { dg-final { scan-tree-dump "__builtin_malloc" "gimple" } } */
+/* { dg-final { scan-tree-dump "__builtin_malloc" "lower" } } */