[gcc r14-12150] LoongArch: Fix PR122097 (2).

[LuluCheng]

https://gcc.gnu.org/g:1dee644fec4defe7b16d7b5e0d512bfee7b2c79f

commit r14-12150-g1dee644fec4defe7b16d7b5e0d512bfee7b2c79f
Author: Lulu Cheng <chenglulu@loongson.cn>
Date:   Mon Nov 3 17:53:52 2025 +0800

    LoongArch: Fix PR122097 (2).
    
    r16-4703 does not completely fix PR122097.  Floating-point vectors
    were not processed in the function loongarch_const_vector_same_bytes_p.
    This patch will completely resolve this issue.
    
            PR target/122097
    
    gcc/ChangeLog:
    
            * config/loongarch/loongarch.cc
            (loongarch_const_vector_same_bytes_p): Add processing for
            floating-point vector data.
    
    (cherry picked from commit e753fa38bb612a3bebe0fc596a44a104bbd2739b)

Diff:
---
 gcc/config/loongarch/loongarch.cc | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index 6a746ffe34bd..a2ed1aef2684 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -1835,7 +1835,27 @@ loongarch_const_vector_same_bytes_p (rtx op, machine_mode mode)
 
   first = CONST_VECTOR_ELT (op, 0);
   bytes = GET_MODE_UNIT_SIZE (mode);
-  val = INTVAL (first);
+
+  if (GET_MODE_CLASS (mode) == MODE_VECTOR_FLOAT)
+    {
+      rtx val_s = CONST_VECTOR_ELT (op, 0);
+      const REAL_VALUE_TYPE *x = CONST_DOUBLE_REAL_VALUE (val_s);
+      if (GET_MODE (val_s) == DFmode)
+	{
+	  long tmp[2];
+	  REAL_VALUE_TO_TARGET_DOUBLE (*x, tmp);
+	  val = (unsigned HOST_WIDE_INT) tmp[1] << 32 | tmp[0];
+	}
+      else
+	{
+	  long tmp;
+	  REAL_VALUE_TO_TARGET_SINGLE (*x, tmp);
+	  val = (unsigned HOST_WIDE_INT) tmp;
+	}
+    }
+  else
+    val = UINTVAL (first);
+
   first_byte = val & 0xff;
   for (i = 1; i < bytes; i++)
     {