On Thu, Aug 8, 2024 at 6:53 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> When we emit .p2align to align BB_HEAD, we must update BB_HEAD. Otherwise
> ENDBR will be inserted as the wrong place.
>
> gcc/
>
> PR target/116174
> * config/i386/i386.cc (ix86_align_loops): Update BB_HEAD when
> aligning BB_HEAD
>
> gcc/testsuite/
>
> PR target/116174
> * gcc.target/i386/pr116174.c: New test.
>
> Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> ---
> gcc/config/i386/i386.cc | 7 +++++--
> gcc/testsuite/gcc.target/i386/pr116174.c | 12 ++++++++++++
> 2 files changed, 17 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr116174.c
>
> diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
> index 77c441893b4..ec6cc5e3548 100644
> --- a/gcc/config/i386/i386.cc
> +++ b/gcc/config/i386/i386.cc
> @@ -23528,8 +23528,11 @@ ix86_align_loops ()
>
> if (padding_p && detect_tight_loop_p)
> {
> - emit_insn_before (gen_max_skip_align (GEN_INT (ceil_log2
> (size)),
> - GEN_INT (0)), label);
> + rtx_insn *align =
> + emit_insn_before (gen_max_skip_align (GEN_INT (ceil_log2
> (size)),
> + GEN_INT (0)), label);
> + if (BB_HEAD (bb) == label)
> + BB_HEAD (bb) = align;
> /* End of function. */
> if (!tbb || tbb == EXIT_BLOCK_PTR_FOR_FN (cfun))
> break;
> diff --git a/gcc/testsuite/gcc.target/i386/pr116174.c
> b/gcc/testsuite/gcc.target/i386/pr116174.c
> new file mode 100644
> index 00000000000..8877d0b51af
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr116174.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile { target *-*-linux* } } */
> +/* { dg-options "-O2 -fcf-protection=branch" } */
> +
> +char *
> +foo (char *dest, const char *src)
> +{
> + while ((*dest++ = *src++) != '\0')
> + /* nothing */;
> + return --dest;
> +}
> +
> +/* { dg-final { scan-assembler "\t\.cfi_startproc\n\tendbr(32|64)\n" } } */
> --
> 2.45.2
>
PING.
--
H.J.
