[gcc r12-8954] Fix unrecognizable insn due to illegal immediate_operand (const_int 255) of QImode.

[hongtao Liu <liuhongt@gcc.gnu.org>]

https://gcc.gnu.org/g:b7306f02da33695bec90f153f6725a51d7c0ac71

commit r12-8954-gb7306f02da33695bec90f153f6725a51d7c0ac71
Author: liuhongt <hongtao.liu@intel.com>
Date:   Mon Nov 28 09:59:47 2022 +0800

    Fix unrecognizable insn due to illegal immediate_operand (const_int 255) of QImode.
    
    For __builtin_ia32_vec_set_v16qi (a, -1, 2) with
    !flag_signed_char. it's transformed to
    __builtin_ia32_vec_set_v16qi (_4, 255, 2) in the gimple,
    and expanded to (const_int 255) in the rtl. But for immediate_operand,
    it expects (const_int 255) to be signed extended to
    (const_int -1). The mismatch caused an unrecognizable insn error.
    
    The patch converts (const_int 255) to (const_int -1) in the backend
    expander.
    
    gcc/ChangeLog:
    
            PR target/107863
            * config/i386/i386-expand.cc (ix86_expand_vec_set_builtin):
            Convert op1 to target mode whenever mode mismatch.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/i386/pr107863.c: New test.

Diff:
---
 gcc/config/i386/i386-expand.cc           | 2 +-
 gcc/testsuite/gcc.target/i386/pr107863.c | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 31780b6daf7..faa63a48bcd 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -12234,7 +12234,7 @@ ix86_expand_vec_set_builtin (tree exp)
   op1 = expand_expr (arg1, NULL_RTX, mode1, EXPAND_NORMAL);
   elt = get_element_number (TREE_TYPE (arg0), arg2);
 
-  if (GET_MODE (op1) != mode1 && GET_MODE (op1) != VOIDmode)
+  if (GET_MODE (op1) != mode1)
     op1 = convert_modes (mode1, GET_MODE (op1), op1, true);
 
   op0 = force_reg (tmode, op0);
diff --git a/gcc/testsuite/gcc.target/i386/pr107863.c b/gcc/testsuite/gcc.target/i386/pr107863.c
new file mode 100644
index 00000000000..99fd85d9765
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr107863.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-mavx2 -O" } */
+
+typedef char v16qi __attribute__((vector_size(16)));
+
+v16qi foo(v16qi a){
+  return __builtin_ia32_vec_set_v16qi (a, -1, 2);
+}