Rewrite the hipe_mode_switch instructions

The 'cmd' variable that were shared by several hipe_mode_switch
instructions would cause clang to produce sub-optimal code,
probably because it considered the instructions as part of of
loop that needed to be optimized.

What would was that 'cmd' would be assigned to the ESI register
(lower 32 bits of the RSI register). It would use ESI for other
purposes in instructions, but at the end of every instruction
it would set ESI to 1 just in case the next instruction happened
to be hipe_trap_return. This can be seen clearly if this commit
is omitted and the define HIPE_MODE_SWITCH_CMD_RETURN in
hipe/hipe_mode_switch.h is changed from 1 to some other number
such as 42. You will see that 42 is assigned to ESI at the end
of every instruction.

Eliminate this problem by elimininating the shared 'cmd' variable.

1 files changed, 15 insertions, 17 deletions

diff --git a/erts/emulator/beam/beam_emu.c b/erts/emulator/beam/beam_emu.c
index 7dbf14de02..362c6e4826 100644
--- a/erts/emulator/beam/beam_emu.c
+++ b/erts/emulator/beam/beam_emu.c
@@ -4681,7 +4681,12 @@ do {						\
 
 #ifdef HIPE
  {
-     unsigned cmd;
+#define HIPE_MODE_SWITCH(Cmd)			\
+     SWAPOUT;					\
+     c_p->fcalls = FCALLS;			\
+     c_p->def_arg_reg[4] = -neg_o_reds;		\
+     c_p = hipe_mode_switch(c_p, Cmd, reg);     \
+     goto L_post_hipe_mode_switch
 
      OpCase(hipe_trap_call): {
 	 /*
@@ -4695,38 +4700,31 @@ do {						\
 	  */
 	 ASSERT(I[-5] == (Uint) OpCode(i_func_info_IaaI));
 	 c_p->hipe.u.ncallee = (void(*)(void)) I[-4];
-	 cmd = HIPE_MODE_SWITCH_CMD_CALL | (I[-1] << 8);
 	 ++hipe_trap_count;
-	 goto L_hipe_mode_switch;
+	 HIPE_MODE_SWITCH(HIPE_MODE_SWITCH_CMD_CALL | (I[-1] << 8));
      }
      OpCase(hipe_trap_call_closure): {
        ASSERT(I[-5] == (Uint) OpCode(i_func_info_IaaI));
        c_p->hipe.u.ncallee = (void(*)(void)) I[-4];
-       cmd = HIPE_MODE_SWITCH_CMD_CALL_CLOSURE | (I[-1] << 8);
        ++hipe_trap_count;
-       goto L_hipe_mode_switch;
+       HIPE_MODE_SWITCH(HIPE_MODE_SWITCH_CMD_CALL_CLOSURE | (I[-1] << 8));
      }
      OpCase(hipe_trap_return): {
-	 cmd = HIPE_MODE_SWITCH_CMD_RETURN;
-	 goto L_hipe_mode_switch;
+	 HIPE_MODE_SWITCH(HIPE_MODE_SWITCH_CMD_RETURN);
      }
      OpCase(hipe_trap_throw): {
-	 cmd = HIPE_MODE_SWITCH_CMD_THROW;
-	 goto L_hipe_mode_switch;
+	 HIPE_MODE_SWITCH(HIPE_MODE_SWITCH_CMD_THROW);
      }
      OpCase(hipe_trap_resume): {
-	 cmd = HIPE_MODE_SWITCH_CMD_RESUME;
-	 goto L_hipe_mode_switch;
+	 HIPE_MODE_SWITCH(HIPE_MODE_SWITCH_CMD_RESUME);
      }
- L_hipe_mode_switch:
-     /* XXX: this abuse of def_arg_reg[] is horrid! */
-     SWAPOUT;
-     c_p->fcalls = FCALLS;
-     c_p->def_arg_reg[4] = -neg_o_reds;
-     c_p = hipe_mode_switch(c_p, cmd, reg);
+#undef HIPE_MODE_SWITCH
+
+ L_post_hipe_mode_switch:
      reg = ERTS_PROC_GET_SCHDATA(c_p)->x_reg_array;
      freg = ERTS_PROC_GET_SCHDATA(c_p)->f_reg_array;
      ERL_BITS_RELOAD_STATEP(c_p);
+     /* XXX: this abuse of def_arg_reg[] is horrid! */
      neg_o_reds = -c_p->def_arg_reg[4];
      FCALLS = c_p->fcalls;
      SWAPIN;