[gcc r14-8414] LoongArch: Remove vec_concatz<mode> pattern.

[LuluCheng <chenglulu@gcc.gnu.org>]

https://gcc.gnu.org/g:77159546b2848b61159ac49882f7b1144e62eaaa

commit r14-8414-g77159546b2848b61159ac49882f7b1144e62eaaa
Author: Jiahao Xu <xujiahao@loongson.cn>
Date:   Wed Jan 24 17:19:13 2024 +0800

    LoongArch: Remove vec_concatz<mode> pattern.
    
    It is incorrect to use vld/vori to implement the vec_concatz<mode> because when the LSX
    instruction is used to update the value of the vector register, the upper 128 bits of
    the vector register will not be zeroed.
    
    gcc/ChangeLog:
    
            * config/loongarch/lasx.md (@vec_concatz<mode>): Remove this define_insn pattern.
            * config/loongarch/loongarch.cc (loongarch_expand_vector_group_init): Use vec_concat<mode>.

Diff:
---
 gcc/config/loongarch/lasx.md      | 15 ---------------
 gcc/config/loongarch/loongarch.cc | 17 ++++++-----------
 2 files changed, 6 insertions(+), 26 deletions(-)

diff --git a/gcc/config/loongarch/lasx.md b/gcc/config/loongarch/lasx.md
index 72f7161311c..5d478b92a2f 100644
--- a/gcc/config/loongarch/lasx.md
+++ b/gcc/config/loongarch/lasx.md
@@ -582,21 +582,6 @@
   [(set_attr "type" "simd_insert")
    (set_attr "mode" "<MODE>")])
 
-(define_insn "@vec_concatz<mode>"
-  [(set (match_operand:LASX 0 "register_operand" "=f")
-    (vec_concat:LASX
-      (match_operand:<VHMODE256_ALL> 1 "nonimmediate_operand")
-      (match_operand:<VHMODE256_ALL> 2 "const_0_operand")))]
-  "ISA_HAS_LASX"
-{
-  if (MEM_P (operands[1]))
-    return "vld\t%w0,%1";
-  else
-    return "vori.b\t%w0,%w1,0";
-}
-  [(set_attr "type" "simd_splat")
-   (set_attr "mode" "<MODE>")])
-
 (define_insn "vec_concat<mode>"
   [(set (match_operand:LASX 0 "register_operand" "=f")
 	(vec_concat:LASX
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index da22fd63e91..dba1252c8f7 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -9917,17 +9917,12 @@ loongarch_expand_vector_group_init (rtx target, rtx vals)
       gcc_unreachable ();
     }
 
-  if (high == CONST0_RTX (half_mode))
-    emit_insn (gen_vec_concatz (vmode, target, low, high));
-  else
-    {
-      if (!register_operand (low, half_mode))
-	low = force_reg (half_mode, low);
-      if (!register_operand (high, half_mode))
-	high = force_reg (half_mode, high);
-      emit_insn (gen_rtx_SET (target,
-			      gen_rtx_VEC_CONCAT (vmode, low, high)));
-    }
+  if (!register_operand (low, half_mode))
+    low = force_reg (half_mode, low);
+  if (!register_operand (high, half_mode))
+    high = force_reg (half_mode, high);
+  emit_insn (gen_rtx_SET (target,
+			  gen_rtx_VEC_CONCAT (vmode, low, high)));
 }
 
 /* Expand initialization of a vector which has all same elements.  */