[Bug target/123116] sbb cst is not produced with direct cond_expr expansion

[ubizjak at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123116

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
Something like this:

diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 7eafdf9ec1b..d59e31ceb66 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -8902,6 +8902,31 @@ (define_peephole2
                             (match_dup 0)))
              (clobber (reg:CC FLAGS_REG))])])

+(define_insn_and_split "*add<mode>3_carry_imm"
+  [(set (match_operand:SWI 0 "nonimmediate_operand")
+       (plus:SWI
+         (plus:SWI
+           (if_then_else:SWI
+             (match_operator:SWI 4 "ix86_carry_flag_operator"
+              [(match_operand 3 "flags_reg_operand") (const_int 0)])
+             (const_int -1)
+             (const_int 0))
+           (match_operand:SWI 1 "nonimmediate_operand"))
+         (match_operand:SWI 2 "const_int_operand")))
+   (clobber (reg:CC FLAGS_REG))]
+  "ix86_binary_operator_ok (PLUS, <MODE>mode, operands, TARGET_APX_NDD)
+   && ix86_pre_reload_split ()"
+  "#"
+  "&& 1"
+   [(parallel
+      [(set (match_dup 0)
+           (minus:SWI
+             (minus:SWI (match_dup 1)
+                        (match_op_dup 4 [(match_dup 3) (const_int 0)]))
+             (match_dup 2)))
+       (clobber (reg:CC FLAGS_REG))])]
+  "operands[2] = gen_int_mode (-INTVAL (operands[2]), <MODE>mode);")
+
 (define_insn "*add<mode>3_carry_2"
   [(set (reg FLAGS_REG)
        (compare