[gcc r14-1630] i386: Fix endless recursion in ix86_expand_vector_init_general with MMX [PR110152]

[Jakub Jelinek <jakub@gcc.gnu.org>]

https://gcc.gnu.org/g:2b2bf793d3fb8980cb2b83e9e2a8c236ad2434f5

commit r14-1630-g2b2bf793d3fb8980cb2b83e9e2a8c236ad2434f5
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Jun 8 10:11:25 2023 +0200

    i386: Fix endless recursion in ix86_expand_vector_init_general with MMX [PR110152]
    
    I'm getting
    +FAIL: gcc.target/i386/3dnow-1.c (internal compiler error: Segmentation fault signal terminated program cc1)
    +FAIL: gcc.target/i386/3dnow-1.c (test for excess errors)
    +FAIL: gcc.target/i386/3dnow-2.c (internal compiler error: Segmentation fault signal terminated program cc1)
    +FAIL: gcc.target/i386/3dnow-2.c (test for excess errors)
    +FAIL: gcc.target/i386/mmx-1.c (internal compiler error: Segmentation fault signal terminated program cc1)
    +FAIL: gcc.target/i386/mmx-1.c (test for excess errors)
    +FAIL: gcc.target/i386/mmx-2.c (internal compiler error: Segmentation fault signal terminated program cc1)
    +FAIL: gcc.target/i386/mmx-2.c (test for excess errors)
    regressions on i686-linux since r14-1166.  The problem is when
    ix86_expand_vector_init_general is called with mmx_ok = true and
    mode = V4HImode, it newly recurses with mmx_ok = false and mode = V2SImode,
    but as mmx_ok is false and !TARGET_SSE, we recurse again with the same
    arguments (ok, fresh new tmp and vals) infinitely.
    The following patch fixes that by passing mmx_ok to that recursive call.
    For n_words == 4 it isn't needed, because we only care about mmx_ok for
    V2SImode or V2SFmode and no other modes.
    
    2023-06-08  Jakub Jelinek  <jakub@redhat.com>
    
            PR target/110152
            * config/i386/i386-expand.cc (ix86_expand_vector_init_general): For
            n_words == 2 recurse with mmx_ok as first argument rather than false.

Diff:
---
 gcc/config/i386/i386-expand.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 697eb475f48..def060ab562 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -16376,7 +16376,7 @@ quarter:
 	  machine_mode concat_mode = tmp_mode == DImode ? V2DImode : V2SImode;
 	  rtx tmp = gen_reg_rtx (concat_mode);
 	  vals = gen_rtx_PARALLEL (concat_mode, gen_rtvec_v (2, words));
-	  ix86_expand_vector_init_general (false, concat_mode, tmp, vals);
+	  ix86_expand_vector_init_general (mmx_ok, concat_mode, tmp, vals);
 	  emit_move_insn (target, gen_lowpart (mode, tmp));
 	}
       else if (n_words == 4)