Hey both,

Sorry about that, don't know how I missed those. Just running a test on that now and will commit when it's done. I assume the comment and 0 -> byte change can be seen as obvious, especially since it was supposed to be in my original patch...

On 27/02/2023 15:46, Richard Sandiford wrote:
Uros Bizjak <ubiz...@gmail.com> writes:
On Fri, Feb 17, 2023 at 8:38 AM Richard Biener <rguent...@suse.de> wrote:

On Thu, 16 Feb 2023, Uros Bizjak wrote:

simplify_subreg can return VOIDmode const_int operand and will
cause ICE in simplify_gen_subreg when this operand is passed to it.

The patch prevents VOIDmode temporary from entering simplify_gen_subreg.
We can't process const_int operand any further, since outermode
is not an integer mode here.

But if it's a CONST_INT then we know it's of int_outermode, no? That is,
doesn't simplify_subreg (mode, ...) always return something in 'mode'
and thus we can always pass just 'mode' as third argument to the
following simplify_gen_subreg call?

You are right. I am testing the attached patch that works too.

Thanks for this, it's the correct fix.  But as noted in
https://gcc.gnu.org/pipermail/gcc-patches/2023-January/610920.html,
the final 0 is also wrong for big-endian.  Andre?

Richard


Uros.

diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 0a1dd88b0a8..3955929bb70 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -7665,7 +7665,7 @@ simplify_context::simplify_subreg (machine_mode 
outermode, rtx op,
      {
        rtx tem = simplify_subreg (int_outermode, op, innermode, byte);
        if (tem)
-       return simplify_gen_subreg (outermode, tem, GET_MODE (tem), 0);
+       return simplify_gen_subreg (outermode, tem, int_outermode, 0);
      }
/* If OP is a vector comparison and the subreg is not changing the

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