[gcc/devel/omp/gcc-9] sccvn: Punt on ref->size not multiple of 8 for memset (, 123, ) in 9.x [PR93945]

[Tobias Burnus]

https://gcc.gnu.org/g:a460bf38dc3582ce1f559cc84084ca27e429b34c

commit a460bf38dc3582ce1f559cc84084ca27e429b34c
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Feb 27 11:21:52 2020 +0100

    sccvn: Punt on ref->size not multiple of 8 for memset (, 123, ) in 9.x [PR93945]
    
    And here is the corresponding 9.x change where we the patch just punts if
    ref->size is not whole bytes, like we already punt if offseti is not byte
    aligned.
    
    2020-02-27  Jakub Jelinek  <jakub@redhat.com>
    
    	PR tree-optimization/93945
    	* tree-ssa-sccvn.c (vn_reference_lookup_3): For memset with non-zero
    	second operand, require ref->size to be a multiple of BITS_PER_UNIT.
    
    	* gcc.c-torture/execute/pr93945.c: New test.

Diff:
---
 gcc/ChangeLog                                 |  6 ++++
 gcc/testsuite/ChangeLog                       |  5 +++
 gcc/testsuite/gcc.c-torture/execute/pr93945.c | 45 +++++++++++++++++++++++++++
 gcc/tree-ssa-sccvn.c                          |  3 +-
 4 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d09456d..c106e96 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/93945
+	* tree-ssa-sccvn.c (vn_reference_lookup_3): For memset with non-zero
+	second operand, require ref->size to be a multiple of BITS_PER_UNIT.
+
 2020-02-26  Carl Love  <cel@us.ibm.com>
 
 	PR target/91276
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 845976a..899b90d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-27  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/93945
+	* gcc.c-torture/execute/pr93945.c: New test.
+
 2020-02-26  Marek Polacek  <polacek@redhat.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr93945.c b/gcc/testsuite/gcc.c-torture/execute/pr93945.c
new file mode 100644
index 0000000..99e455c
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr93945.c
@@ -0,0 +1,45 @@
+/* PR tree-optimization/93945 */
+
+union U { char a[8]; struct S { unsigned int b : 8, c : 13, d : 11; } e; } u;
+
+__attribute__((noipa)) int
+foo (void)
+{
+  __builtin_memset (&u.a, 0xf4, sizeof (u.a));
+  return u.e.c;
+}
+
+__attribute__((noipa)) int
+bar (void)
+{
+  asm volatile ("" : : "g" (&u) : "memory");
+  return u.e.c;
+}
+
+__attribute__((noipa)) int
+baz (void)
+{
+  __builtin_memset (&u.a, 0xf4, sizeof (u.a));
+  return u.e.d;
+}
+
+__attribute__((noipa)) int
+qux (void)
+{
+  asm volatile ("" : : "g" (&u) : "memory");
+  return u.e.d;
+}
+
+int
+main ()
+{
+  int a = foo ();
+  int b = bar ();
+  if (a != b)
+    __builtin_abort ();
+  a = baz ();
+  b = qux ();
+  if (a != b)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index aea11bd..32f45c9 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -2113,7 +2113,8 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
 	       || (INTEGRAL_TYPE_P (vr->type) && known_eq (ref->size, 8)))
 	      && CHAR_BIT == 8 && BITS_PER_UNIT == 8
 	      && offset.is_constant (&offseti)
-	      && offseti % BITS_PER_UNIT == 0))
+	      && offseti % BITS_PER_UNIT == 0
+	      && multiple_p (ref->size, BITS_PER_UNIT)))
       && poly_int_tree_p (gimple_call_arg (def_stmt, 2))
       && (TREE_CODE (gimple_call_arg (def_stmt, 0)) == ADDR_EXPR
 	  || TREE_CODE (gimple_call_arg (def_stmt, 0)) == SSA_NAME))