Hi!
Boolean !x is often expanded as ^ 1, but store merging it actually merges
as ^ 255 (for 8-bit bool), which is incorrect.
The following patch fixes it to do that ^ 1 instead.
Bootstrapped/regtested on x86_64-linux and i686-linux and checked on the
testcase with -> powerpc64-linux cross, ok for trunk?
2018-03-20 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/84982
* gimple-ssa-store-merging.c (invert_op): Handle boolean inversion
by flipping the least significant bit rather than all bits from
bitpos to bitpos + bitsize - 1.
* c-c++-common/pr84982.c: New test.
--- gcc/gimple-ssa-store-merging.c.jj 2018-03-20 13:53:31.701938584 +0100
+++ gcc/gimple-ssa-store-merging.c 2018-03-20 14:39:50.925657339 +0100
@@ -3248,16 +3248,22 @@ invert_op (split_store *split_store, int
unsigned int i;
store_immediate_info *info;
unsigned int cnt = 0;
+ bool any_bools = false;
FOR_EACH_VEC_ELT (split_store->orig_stores, i, info)
{
bool bit_not_p = idx < 2 ? info->ops[idx].bit_not_p : info->bit_not_p;
if (bit_not_p)
- ++cnt;
+ {
+ ++cnt;
+ tree lhs = gimple_assign_lhs (info->stmt);
+ if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE && info->bitsize > 1)
+ any_bools = true;
+ }
}
mask = NULL_TREE;
if (cnt == 0)
return NOP_EXPR;
- if (cnt == split_store->orig_stores.length ())
+ if (cnt == split_store->orig_stores.length () && !any_bools)
return BIT_NOT_EXPR;
unsigned HOST_WIDE_INT try_bitpos = split_store->bytepos * BITS_PER_UNIT;
@@ -3275,13 +3281,34 @@ invert_op (split_store *split_store, int
set in the mask. */
unsigned HOST_WIDE_INT bitsize = info->bitsize;
unsigned int pos_in_buffer = 0;
+ bool is_bool = false;
+ if (any_bools && bitsize > 1)
+ {
+ tree lhs = gimple_assign_lhs (info->stmt);
+ if (TREE_CODE (TREE_TYPE (lhs)) == BOOLEAN_TYPE)
+ is_bool = true;
+ }
if (info->bitpos < try_bitpos)
{
gcc_assert (info->bitpos + bitsize > try_bitpos);
bitsize -= (try_bitpos - info->bitpos);
+ if (is_bool && !BYTES_BIG_ENDIAN)
+ continue;
}
else
pos_in_buffer = info->bitpos - try_bitpos;
+ if (is_bool && bitsize)
+ {
+ /* If this is a bool inversion, invert just the LSB
+ rather than all bits of it. */
+ if (BYTES_BIG_ENDIAN)
+ {
+ pos_in_buffer += bitsize - 1;
+ if (pos_in_buffer >= split_store->size)
+ continue;
+ }
+ bitsize = 1;
+ }
if (pos_in_buffer + bitsize > split_store->size)
bitsize = split_store->size - pos_in_buffer;
unsigned char *p = buf + (pos_in_buffer / BITS_PER_UNIT);
--- gcc/testsuite/c-c++-common/pr84982.c.jj 2018-03-20 14:49:00.259744750
+0100
+++ gcc/testsuite/c-c++-common/pr84982.c 2018-03-20 12:27:34.111363552
+0100
@@ -0,0 +1,38 @@
+/* PR tree-optimization/84982 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#ifndef __cplusplus
+#define bool _Bool
+#define true 1
+#define false 0
+#endif
+
+struct S { bool a, b, c, d; };
+
+__attribute__((noipa)) void
+bar (bool *x)
+{
+ if (x[0] || !x[1] || !x[2] || x[3])
+ __builtin_abort ();
+}
+
+__attribute__((noipa)) void
+foo (struct S *x)
+{
+ bool a[4];
+ a[0] = !x->a;
+ a[1] = !x->b;
+ a[2] = x->c;
+ a[3] = !x->d;
+ bar (a);
+}
+
+int
+main ()
+{
+ struct S s;
+ s.a = true; s.b = false; s.c = true; s.d = true;
+ foo (&s);
+ return 0;
+}
Jakub
