[Bug target/81034] New: [x86] Broken IRA pass when printing results of intrinsic execution

[sebastian.peryt at intel dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81034

            Bug ID: 81034
           Summary: [x86] Broken IRA pass when printing results of
                    intrinsic execution
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sebastian.peryt at intel dot com
  Target Milestone: ---
            Target: x86_64-*-*, i?86-*-*

Created attachment 41516
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41516&action=edit
Reproducible

During missing intrinsic implementation I found strange bug connected to
printf. The reproducer is attached.

The intrinsics I've been implementing are _mm_mask_load_sd and
_mm_maskz_load_sd. Both of them use the same md. Unfortunately, with
_mm_maskz_load_sd, when I want to printf values that were generated for some
particular cases it breaks compilation and results in following error:

during RTL pass: ira
In file included from
/gcc/gcc/testsuite/gcc.target/i386/avx512f-vmovsd-2.c:5:0:
/gcc/gcc/testsuite/gcc.target/i386/avx512f-check.h: In function ‘do_test’:
/gcc/gcc/testsuite/gcc.target/i386/avx512f-check.h:11:1: internal compiler
error: in wide_int_to_tree, at tree.c:1487
0xe9e9f3 wide_int_to_tree(tree_node*,
generic_wide_int<wide_int_ref_storage<false> > const&)
        ../../gcc/gcc/tree.c:1487
0x895df6 make_tree(tree_node*, rtx_def*)
        ../../gcc/gcc/expmed.c:5113
0x895e8b make_tree(tree_node*, rtx_def*)
        ../../gcc/gcc/expmed.c:5139
0xee83a2 force_const_mem(machine_mode, rtx_def*)
        ../../gcc/gcc/varasm.c:3733
0xa1652b setup_reg_equiv
        ../../gcc/gcc/ira.c:3992
0xa1652b ira
        ../../gcc/gcc/ira.c:5244
0xa1652b execute
        ../../gcc/gcc/ira.c:5580

To reproduce this error two conditions has to be met:
- mask value has to be either 0 or 2
- optimization has to be O2, O3 or Ofast

It is also interesting that for Os optimization it works.

When printf of res4 in attached code is commented out it also compiles. On the
other hand, for res3 printf doesn't make a difference - it always works.

I have compared passes' dumps for version with res4 printf and without and I
found some interesting discrepancies there:
1. On 029t.einline pass, in compiling (non-printf) version function do_test ()
has been partially expanded by what looks like to be the content of
avx512f_test () function.
2. On 051i.ipa_oacc pass the order of functions in dump files has been changed
and optimized - for non-compiling one setting the order:
  a.avx512f_test ()
  b.main ()
  c.do_test ()
and for compiling one:
  a.main ()
  b.do_test ()
3. On 087t.fixup_cfg4 pass main () is totally deleted from not compiling
version leaving only do_test ().

I would appreciate any input on that issue.