middle-end/94206 fix memset folding to avoid types with padding

This makes sure that the store a memset is folded to uses a type
covering all bits.

2020-03-18   Richard Biener  <rguenther@suse.de>

	PR middle-end/94206
	* gimple-fold.c (gimple_fold_builtin_memset): Avoid using
	partial int modes or not mode-precision integer types for
	the store.

	* gcc.dg/torture/pr94206.c: New testcase.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 092e853a187ea6bbb4fcc3d918beebca4b043260..167c1055ec90184e7847e503af3309bc32686dae 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2020-04-02  Richard Biener  <rguenther@suse.de>
+
+       Backport from mainline
+       2020-03-18  Richard Biener  <rguenther@suse.de>
+
+       PR middle-end/94206
+       * gimple-fold.c (gimple_fold_builtin_memset): Avoid using
+       partial int modes or not mode-precision integer types for
+       the store.
+
 2020-04-02  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/94435

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index d00f1e2b035e749145795296cd4613df9bc126a1..408b93b22001201c04ed8c58de4088545bf8ee1f 100644 (file)
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -1242,12 +1242,18 @@ gimple_fold_builtin_memset (gimple_stmt_iterator *gsi, tree c, tree len)
 
   length = tree_to_uhwi (len);
   if (GET_MODE_SIZE (SCALAR_INT_TYPE_MODE (etype)) != length
+      || (GET_MODE_PRECISION (SCALAR_INT_TYPE_MODE (etype))
+         != GET_MODE_BITSIZE (SCALAR_INT_TYPE_MODE (etype)))
       || get_pointer_alignment (dest) / BITS_PER_UNIT < length)
     return NULL_TREE;
 
   if (length > HOST_BITS_PER_WIDE_INT / BITS_PER_UNIT)
     return NULL_TREE;
 
+  if (!type_has_mode_precision_p (etype))
+    etype = lang_hooks.types.type_for_mode (SCALAR_INT_TYPE_MODE (etype),
+                                           TYPE_UNSIGNED (etype));
+
   if (integer_zerop (c))
     cval = 0;
   else

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index bcf4ff335e9b4c621ace451fb1ca0c94ad3e979d..2b67e242ca5b7542fddbc4505204cf28b35b8bbc 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2020-04-02  Richard Biener  <rguenther@suse.de>
+
+       Backport from mainline
+       2020-03-18  Richard Biener  <rguenther@suse.de>
+
+       PR middle-end/94206
+       * gcc.dg/torture/pr94206.c: New testcase.
+
 2020-04-02  Jakub Jelinek  <jakub@redhat.com>
 
        PR target/94435

diff --git a/gcc/testsuite/gcc.dg/torture/pr94206.c b/gcc/testsuite/gcc.dg/torture/pr94206.c
new file mode 100644 (file)
index 0000000..9e54bba
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr94206.c
@@ -0,0 +1,17 @@
+/* { dg-do run { target lp64 } } */
+
+struct {
+    unsigned long x:33;
+} s;
+typedef __typeof__(s.x + 0) uint33;
+
+int main()
+{
+  uint33 x;
+  __builtin_memset(&x, -1, sizeof x);
+  unsigned long u;
+  __builtin_memcpy(&u, &x, sizeof u);
+  if (u != -1ul)
+    __builtin_abort ();
+  return 0;
+}