[PATCH] LoongArch: extract the base address to promote the combine of RTX.

[zhaozhou]

When use 256 bits vec for move src to dest, extract the base address
what plus operation to promote the combine of RTX.

gcc/ChangeLog:

        * config/loongarch/loongarch.cc: Extract plus operation.

gcc/testsuite/ChangeLog:

        * gcc.target/loongarch/vector/lasx/lasx-struct-move.c: New test.
---
 gcc/config/loongarch/loongarch.cc               | 10 ++++++++++
 .../loongarch/vector/lasx/lasx-struct-move.c    | 17 +++++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 
gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-struct-move.c

diff --git a/gcc/config/loongarch/loongarch.cc 
b/gcc/config/loongarch/loongarch.cc
index fcca0ec8252..848ed868473 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -5922,6 +5922,16 @@ loongarch_block_move_straight (rtx dest, rtx src, 
HOST_WIDE_INT length,
   /* Allocate a buffer for the temporary registers.  */
   regs = XALLOCAVEC (rtx, num_reg);
 
+  /* Extract the base address what plus operation to promote the combine of
+     RTX.  */
+  if (GET_CODE (XEXP (dest, 0)) == PLUS)
+    {
+      unsigned int dest_align = MEM_ALIGN (dest);
+      rtx dest_reg = copy_addr_to_reg (XEXP (dest, 0));
+      dest = change_address (dest, BLKmode, dest_reg);
+      set_mem_align (dest, dest_align);
+    }
+
   for (delta_cur = delta, i = 0, offs = 0; offs < length; delta_cur /= 2)
     {
       mode = loongarch_mode_for_move_size (delta_cur);
diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-struct-move.c 
b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-struct-move.c
new file mode 100644
index 00000000000..ca10e9f47a6
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-struct-move.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -lasx" } */
+
+struct vec
+{
+  int vec_a[32];
+  double vec_b[5];
+  char vec_c[32];
+};
+
+void
+foo (struct vec *dest, struct vec *src, int index)
+{
+  dest[index] = *src;
+}
+
+/* { dg-final { scan-assembler-times "alsl\.d" 3} } */
-- 
2.20.1