https://gcc.gnu.org/g:587b370c8492aadaab14c57e242c66778cc78891
commit r12-10987-g587b370c8492aadaab14c57e242c66778cc78891
Author: Richard Sandiford <richard.sandif...@arm.com>
Date: Tue Mar 11 15:51:55 2025 +0000
Fix folding of BIT_NOT_EXPR for POLY_INT_CST [PR118976]
There was an embarrassing typo in the folding of BIT_NOT_EXPR for
POLY_INT_CSTs: it used - rather than ~ on the poly_int. Not sure
how that happened, but it might have been due to the way that
~x is implemented as -1 - x internally.
gcc/
PR tree-optimization/118976
* fold-const.cc (const_unop): Use ~ rather than - for BIT_NOT_EXPR.
* config/aarch64/aarch64.cc (aarch64_test_sve_folding): New
function.
(aarch64_run_selftests): Run it.
(cherry picked from commit 78380fd7f743e23dfdf013d68a2f0347e1511550)
Diff:
---
gcc/config/aarch64/aarch64.cc | 11 +++++++++++
gcc/fold-const.cc | 2 +-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index be0d958dcf6b..72d737d62228 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -27541,6 +27541,16 @@ aarch64_test_fractional_cost ()
ASSERT_EQ (cf (1, 2).as_double (), 0.5);
}
+/* Test SVE arithmetic folding. */
+
+static void
+aarch64_test_sve_folding ()
+{
+ tree res = fold_unary (BIT_NOT_EXPR, ssizetype,
+ ssize_int (poly_int64 (1, 1)));
+ ASSERT_TRUE (operand_equal_p (res, ssize_int (poly_int64 (-2, -1))));
+}
+
/* Run all target-specific selftests. */
static void
@@ -27548,6 +27558,7 @@ aarch64_run_selftests (void)
{
aarch64_test_loading_full_dump ();
aarch64_test_fractional_cost ();
+ aarch64_test_sve_folding ();
}
} // namespace selftest
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index d81a71c41a17..391f11095408 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -1802,7 +1802,7 @@ const_unop (enum tree_code code, tree type, tree arg0)
if (TREE_CODE (arg0) == INTEGER_CST)
return fold_not_const (arg0, type);
else if (POLY_INT_CST_P (arg0))
- return wide_int_to_tree (type, -poly_int_cst_value (arg0));
+ return wide_int_to_tree (type, ~poly_int_cst_value (arg0));
/* Perform BIT_NOT_EXPR on each element individually. */
else if (TREE_CODE (arg0) == VECTOR_CST)
{
