On April 10, 2021 8:07:57 AM GMT+02:00, Jakub Jelinek <ja...@redhat.com> wrote:
>Hi!
>
>This is a sequel to the PR85022 changes, inline-asm can (unfortunately)
>introduce VOIDmode MEMs and in PR85022 they have been changed so that
>we don't pretend we know their size (as opposed to assuming they have
>zero size).
>
>This time we ICE in rtx_addr_can_trap_p_1 because it assumes that
>all memory but BLKmode has known size. The patch just treats VOIDmode
>MEMs like BLKmode in that regard. And, the STRICT_ALIGNMENT change
>is needed because VOIDmode has GET_MODE_SIZE of 0 and we don't want to
>check if something is a multiple of 0.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok.
We can experiment with differnt canonicalization in GCC 12.
Richard.
>2021-04-10 Jakub Jelinek <ja...@redhat.com>
>
> PR rtl-optimization/98601
> * rtlanal.c (rtx_addr_can_trap_p_1): Allow in assert unknown size
> not just for BLKmode, but also for VOIDmode. For STRICT_ALIGNMENT
> unaligned_mems handle VOIDmode like BLKmode.
>
> * gcc.dg/torture/pr98601.c: New test.
>
>--- gcc/rtlanal.c.jj 2021-03-05 21:51:48.689185518 +0100
>+++ gcc/rtlanal.c 2021-04-09 11:15:20.341906331 +0200
>@@ -464,12 +464,17 @@ rtx_addr_can_trap_p_1 (const_rtx x, poly
> machine_mode mode, bool unaligned_mems)
> {
> enum rtx_code code = GET_CODE (x);
>- gcc_checking_assert (mode == BLKmode || known_size_p (size));
>+ gcc_checking_assert (mode == BLKmode
>+ || mode == VOIDmode
>+ || known_size_p (size));
> poly_int64 const_x1;
>
>/* The offset must be a multiple of the mode size if we are considering
> unaligned memory references on strict alignment machines. */
>- if (STRICT_ALIGNMENT && unaligned_mems && mode != BLKmode)
>+ if (STRICT_ALIGNMENT
>+ && unaligned_mems
>+ && mode != BLKmode
>+ && mode != VOIDmode)
> {
> poly_int64 actual_offset = offset;
>
>--- gcc/testsuite/gcc.dg/torture/pr98601.c.jj 2021-04-09
>11:18:26.964817854 +0200
>+++ gcc/testsuite/gcc.dg/torture/pr98601.c 2021-04-09
>11:18:16.758932053 +0200
>@@ -0,0 +1,14 @@
>+/* PR rtl-optimization/98601 */
>+/* { dg-do compile } */
>+
>+void
>+foo (void *p)
>+{
>+ asm ("" : "=m" (*p)); /* { dg-warning "dereferencing
>'void \\*'
>pointer" } */
>+}
>+
>+void
>+bar (void *p)
>+{
>+ asm volatile ("" : : "m" (*p)); /* { dg-warning "dereferencing 'void
>\\*' pointer" } */
>+}
>
> Jakub
