[PATCH] PR target/79498: Properly store 128-bit constant in large model

[H.J. Lu]

When converting TI store with CONST_INT to V1TI store with CONST_VECTOR
in large model, an extra instruction may be needed to load CONST_VECTOR
into a register.  Insert the extra instruction to the right place.

Tested on x86-64.  I am checking in this pre-approved patch.

Thanks.

H.J.
---
gcc/

        PR target/79498
        * config/i386/i386.c (timode_scalar_chain::convert_insn): Insert
        the extra instruction to the right place to store 128-bit constant
        when needed.

gcc/testsuite/

        PR target/79498
        * gcc.target/i386/pr79498.c: New test.
---
 gcc/config/i386/i386.c                  |  5 +++++
 gcc/testsuite/gcc.target/i386/pr79498.c | 20 ++++++++++++++++++++
 2 files changed, 25 insertions(+)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr79498.c

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index d7dce4b..02287fd 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -3956,8 +3956,13 @@ timode_scalar_chain::convert_insn (rtx_insn *insn)
          /* Since there are no instructions to store 128-bit constant,
             temporary register usage is required.  */
          rtx tmp = gen_reg_rtx (V1TImode);
+         start_sequence ();
          src = gen_rtx_CONST_VECTOR (V1TImode, gen_rtvec (1, src));
          src = validize_mem (force_const_mem (V1TImode, src));
+         rtx_insn *seq = get_insns ();
+         end_sequence ();
+         if (seq)
+           emit_insn_before (seq, insn);
          emit_conversion_insns (gen_rtx_SET (dst, tmp), insn);
          dst = tmp;
        }
diff --git a/gcc/testsuite/gcc.target/i386/pr79498.c 
b/gcc/testsuite/gcc.target/i386/pr79498.c
new file mode 100644
index 0000000..8f62393
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr79498.c
@@ -0,0 +1,20 @@
+/* PR target/79498 */
+/* { dg-do compile { target lp64 } } */
+/* { dg-options "-O2 -mno-avx512f -mcmodel=large -Wno-psabi" } */
+
+typedef unsigned U __attribute__ ((vector_size (64)));
+typedef unsigned __int128 V __attribute__ ((vector_size (64)));
+
+static inline V
+bar (U u, U x, V v)
+{
+  v = (V)(U) { 0, ~0 };
+  v[x[0]] <<= u[-63];
+  return v;
+}
+
+V
+foo (U u)
+{
+  return bar (u, (U) {}, (V) {});
+}
-- 
2.9.3