[PATCH] Eliminate redundant vpextrq/vpinsrq when move TI to V4SI.

[liuhongt]

r14-1902-g96c3539f2a3813 split TImode move with 2 DImode move, it's
supposed to optimize TImode in parameter/return since accoring to
psABI it's stored into 2 general registers.

But when TImode is not in parameter/return, it could create redundancy
in the PR.

The patch add a splitter to handle that.

.i.e.
(insn 10 9 14 2 (set (subreg:V2DI (reg:V4SI 98 [ <retval> ]) 0)
                     (vec_concat:V2DI (subreg:DI (reg:TI 101) 0)
                         (subreg:DI (reg:TI 101) 8)))
                         8442 {vec_concatv2di}
                        (expr_list:REG_DEAD (reg:TI 101)

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ok for trunk and backport?

gcc/ChangeLog:

        PR target/121274
        * config/i386/sse.md (*vec_concatv2di_0): Add a splitter
        before it.

gcc/testsuite/ChangeLog:

        * gcc.target/i386/pr121274.c: New test.
---
 gcc/config/i386/sse.md                   | 13 +++++++++++++
 gcc/testsuite/gcc.target/i386/pr121274.c | 24 ++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr121274.c

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index d88c3d60bff..ec74f93731d 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -21729,6 +21729,19 @@ (define_insn "vec_concatv2di"
           (const_string "orig")))
    (set_attr "mode" "TI,TI,TI,TI,TI,TI,V4SF,V2SF,V2SF")])
 
+;; Eliminate redundancy caused by
+;; /* Special case TImode to 128-bit vector conversions via V2DI.  */
+;; in ix86_expand_vector_move
+
+(define_split
+  [(set (match_operand:V2DI 0 "register_operand")
+       (vec_concat:V2DI
+         (subreg:DI (match_operand:TI 1 "register_operand") 0)
+         (subreg:DI (match_dup 1) 8)))]
+  "TARGET_SSE2 && ix86_pre_reload_split ()"
+  [(set (match_dup 0)
+       (subreg:V2DI (match_dup 1) 0))])
+
 (define_insn "*vec_concatv2di_0"
   [(set (match_operand:V2DI 0 "register_operand"     "=v,v ,x")
        (vec_concat:V2DI
diff --git a/gcc/testsuite/gcc.target/i386/pr121274.c 
b/gcc/testsuite/gcc.target/i386/pr121274.c
new file mode 100644
index 00000000000..16760cfcbac
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr121274.c
@@ -0,0 +1,24 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-march=x86-64-v4 -O2" } */
+/* { dg-final { scan-assembler-not "vpextrq" } } */
+/* { dg-final { scan-assembler-not "vpinsrq" } } */
+
+typedef int v16si __attribute__((vector_size(64)));
+typedef int v4si __attribute__((vector_size(16)));
+
+v4si f(v16si x)
+{
+  return __builtin_shufflevector(x, x, 0, 1, 2, 3);
+}
+
+v4si g(v16si x)
+{
+return __builtin_shufflevector(x, x, 4, 5, 6, 7);
+}
+
+v4si f1(__int128 *x)
+{
+  __int128 t = *x;
+  asm("":"+x"(t));
+  return (v4si)t;
+}
-- 
2.34.1