The testcase confuses the code that detects min and max len for the
memset, so max_len ends up less than min_len. That shouldn't be
possible, but the testcase requires us to handle this case.
The store-by-mult-pieces algorithm actually relies on min and max
lengths, so if we find them to be inconsistent, the best we can do is
punting.
Regstrapped on x86_64-linux-gnu. Ok to install?
for gcc/ChangeLog
PR middle-end/100843
* builtins.c (try_store_by_multiple_pieces): Fail if min_len
is greater than max_len.
for gcc/testsuite/ChangeLog
PR middle-end/100843
* gcc.dg/pr100843.c: New.
---
gcc/builtins.c | 3 ++-
gcc/testsuite/gcc.dg/pr100843.c | 8 ++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/pr100843.c
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 03829c03a5a11..304d87dafb750 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -3963,7 +3963,8 @@ try_store_by_multiple_pieces (rtx to, rtx len, unsigned
int ctz_len,
else if (max_len == min_len)
blksize = max_len;
else
- gcc_unreachable ();
+ /* Huh, max_len < min_len? Punt. See pr100843.c. */
+ return false;
if (min_len >= blksize)
{
min_len -= blksize;
diff --git a/gcc/testsuite/gcc.dg/pr100843.c b/gcc/testsuite/gcc.dg/pr100843.c
new file mode 100644
index 0000000000000..695a2ec3f6818
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr100843.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -w" } */
+
+char c;
+void *memset();
+void test_integer_conversion_memset(void *d) {
+ memset(d, '\0', c);
+}
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts. Ask me about <https://stallmansupport.org>
