https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91528
--- Comment #3 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Richard Biener from comment #1)
> (gdb) p x_rtl.drap_reg
> $1 = (rtx) 0x0
>
> so
>
> 7843 /* Only need to push parameter pointer reg if it is caller
> saved. */
> 7844 if (!call_used_regs[REGNO (crtl->drap_reg)])
> 7845 {
>
> segfaults. This must be really a latent issue. I guess
>
> /* Conversion means we may have 128bit register spills/fills
> which require aligned stack. */
> if (converted_insns)
> {
> if (crtl->stack_alignment_needed < 128)
> ...
>
> needs to do some magic for -mforce-drap (which might be handled too early,
> ignoring the late generated xmm uses?)
When changing stack_alignment_{needed,estimated}, we also need to update
dependent crtl variables, similar to what expand_stack_alignment from
cfgexpand.c does. Following (untested) patch fixes the testcase failure:
--cut here--
diff --git a/gcc/config/i386/i386-features.c b/gcc/config/i386/i386-features.c
index fb7ac1b7d102..594b572454df 100644
--- a/gcc/config/i386/i386-features.c
+++ b/gcc/config/i386/i386-features.c
@@ -1770,6 +1770,28 @@ convert_scalars_to_vector (bool timode_p)
crtl->stack_alignment_needed = 128;
if (crtl->stack_alignment_estimated < 128)
crtl->stack_alignment_estimated = 128;
+
+ crtl->stack_realign_needed
+ = INCOMING_STACK_BOUNDARY < crtl->stack_alignment_estimated;
+ crtl->stack_realign_tried = crtl->stack_realign_needed;
+
+ crtl->stack_realign_processed = true;
+
+ rtx drap_rtx = targetm.calls.get_drap_rtx ();
+
+ /* stack_realign_drap and drap_rtx must match. */
+ gcc_assert ((stack_realign_drap != 0) == (drap_rtx != NULL));
+
+ /* Do nothing if NULL is returned, which means DRAP is not needed. */
+ if (drap_rtx != NULL)
+ {
+ crtl->args.internal_arg_pointer = drap_rtx;
+
+ /* Call fixup_tail_calls to clean up REG_EQUIV note if DRAP is
+ needed. */
+ fixup_tail_calls ();
+ }
+
/* Fix up DECL_RTL/DECL_INCOMING_RTL of arguments. */
if (TARGET_64BIT)
for (tree parm = DECL_ARGUMENTS (current_function_decl);
--cut here--
HJ, can you please take the patch from here? Realignment stuff is a bit of
mistery to me.
