[PATCH v1] LoongArch: Fix vec_initv32qiv16qi template to avoid ICE.

[Chenghui Pan]

Following test code triggers unrecognized insn ICE on LoongArch target
with "-O3 -mlasx":

void
foo (unsigned char *dst, unsigned char *src)
{
  for (int y = 0; y < 16; y++)
    {
      for (int x = 0; x < 16; x++)
        dst[x] = src[x] + 1;
      dst += 32;
      src += 32;
    }
}

ICE info:
./test.c: In function ‘foo’:
./test.c:8:1: error: unrecognizable insn:
    8 | }
      | ^
(insn 15 14 16 4 (set (reg:V32QI 185 [ vect__24.7 ])
        (vec_concat:V32QI (reg:V16QI 186)
            (const_vector:V16QI [
                    (const_int 0 [0]) repeated x16
                ]))) "./test.c":4:19 -1
     (nil))
during RTL pass: vregs
./test.c:8:1: internal compiler error: in extract_insn, at recog.cc:2791
0x12028023b _fatal_insn(char const*, rtx_def const*, char const*, int, char 
const*)
        /home/panchenghui/upstream/gcc/gcc/rtl-error.cc:108
0x12028026f _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        /home/panchenghui/upstream/gcc/gcc/rtl-error.cc:116
0x120a03c5b extract_insn(rtx_insn*)
        /home/panchenghui/upstream/gcc/gcc/recog.cc:2791
0x12067ff73 instantiate_virtual_regs_in_insn
        /home/panchenghui/upstream/gcc/gcc/function.cc:1610
0x12067ff73 instantiate_virtual_regs
        /home/panchenghui/upstream/gcc/gcc/function.cc:1983
0x12067ff73 execute
        /home/panchenghui/upstream/gcc/gcc/function.cc:2030

This RTL is generated inside loongarch_expand_vector_group_init function 
(related
to vec_initv32qiv16qi template). Original impl doesn't ensure all vec_concat 
arguments
are register type. This patch adds force_reg() to the vec_concat argument 
generation.

gcc/ChangeLog:

        * config/loongarch/loongarch.cc (loongarch_expand_vector_group_init):
          fix impl related to vec_initv32qiv16qi template to avoid ICE.

gcc/testsuite/ChangeLog:

        * gcc.target/loongarch/vector/lasx/lasx-vec-init-1.c: New test.
---
 gcc/config/loongarch/loongarch.cc                  |  3 ++-
 .../loongarch/vector/lasx/lasx-vec-init-1.c        | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 
gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-vec-init-1.c

diff --git a/gcc/config/loongarch/loongarch.cc 
b/gcc/config/loongarch/loongarch.cc
index 3420e002efc..14dd0db1674 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -10206,7 +10206,8 @@ loongarch_gen_const_int_vector_shuffle (machine_mode 
mode, int val)
 void
 loongarch_expand_vector_group_init (rtx target, rtx vals)
 {
-  rtx ops[2] = { XVECEXP (vals, 0, 0), XVECEXP (vals, 0, 1) };
+  rtx ops[2] = { force_reg (E_V16QImode, XVECEXP (vals, 0, 0)),
+      force_reg (E_V16QImode, XVECEXP (vals, 0, 1)) };
   emit_insn (gen_rtx_SET (target, gen_rtx_VEC_CONCAT (E_V32QImode, ops[0],
                                                      ops[1])));
 }
diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-vec-init-1.c 
b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-vec-init-1.c
new file mode 100644
index 00000000000..28be329822e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/vector/lasx/lasx-vec-init-1.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+void
+foo (unsigned char *dst, unsigned char *src)
+{
+  for (int y = 0; y < 16; y++)
+    {
+      for (int x = 0; x < 16; x++)
+        dst[x] = src[x] + 1;
+      dst += 32;
+      src += 32;
+    }
+}
-- 
2.36.0