[gcc r16-811] aarch64: Carry over zeroness in aarch64_evpc_reencode

[Pengxuan Zheng via Gcc-cvs]

https://gcc.gnu.org/g:84c6988c026114727693cd7cd74b8cd5cdcdeb74

commit r16-811-g84c6988c026114727693cd7cd74b8cd5cdcdeb74
Author: Pengxuan Zheng <quic_pzh...@quicinc.com>
Date:   Tue May 20 17:58:23 2025 -0700

    aarch64: Carry over zeroness in aarch64_evpc_reencode
    
    There was a bug in aarch64_evpc_reencode which could leave zero_op0_p and
    zero_op1_p of the struct "newd" uninitialized.  r16-701-gd77c3bc1c35e303 
fixed
    the issue by zero initializing "newd."  This patch provides an alternative 
fix
    as suggested by Richard Sandiford based on the fact that the zeroness is
    preserved by aarch64_evpc_reencode.
    
    gcc/ChangeLog:
    
            * config/aarch64/aarch64.cc (aarch64_evpc_reencode): Copy 
zero_op0_p and
            zero_op1_p from d to newd.
    
    Signed-off-by: Pengxuan Zheng <quic_pzh...@quicinc.com>

Diff:
---
 gcc/config/aarch64/aarch64.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/gcc/config/aarch64/aarch64.cc b/gcc/config/aarch64/aarch64.cc
index 1da615c8955a..2b837ec8e673 100644
--- a/gcc/config/aarch64/aarch64.cc
+++ b/gcc/config/aarch64/aarch64.cc
@@ -26327,7 +26327,7 @@ aarch64_evpc_trn (struct expand_vec_perm_d *d)
 static bool
 aarch64_evpc_reencode (struct expand_vec_perm_d *d)
 {
-  expand_vec_perm_d newd = {};
+  expand_vec_perm_d newd;
 
   /* The subregs that we'd create are not supported for big-endian SVE;
      see aarch64_modes_compatible_p for details.  */
@@ -26353,6 +26353,8 @@ aarch64_evpc_reencode (struct expand_vec_perm_d *d)
   newd.op1 = d->op1 ? gen_lowpart (new_mode, d->op1) : NULL;
   newd.testing_p = d->testing_p;
   newd.one_vector_p = d->one_vector_p;
+  newd.zero_op0_p = d->zero_op0_p;
+  newd.zero_op1_p = d->zero_op1_p;
 
   newd.perm.new_vector (newpermindices.encoding (), newd.one_vector_p ? 1 : 2,
                        newpermindices.nelts_per_input ());