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Re: patch for PR82444




On 02/01/2018 12:10 PM, Richard Sandiford wrote:
Vladimir Makarov <vmakarov@redhat.com> writes:
Not sure about the E_<mode>/genmodes reference here.  Isn't it simply
"because it might be the mode a pseudo register"?

Is it OK to expand the explanation a bit, as below?

Yes, it is OK.  It is a better explanation.  Thank you, Richard.
2018-02-01  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/
	* ira.c (ira_init_register_move_cost): Adjust comment.

Index: gcc/ira.c
===================================================================
--- gcc/ira.c	2018-02-01 17:09:45.998165072 +0000
+++ gcc/ira.c	2018-02-01 17:09:46.150158481 +0000
@@ -1578,8 +1578,10 @@ ira_init_register_move_cost (machine_mod
    ira_assert (ira_register_move_cost[mode] == NULL
  	      && ira_may_move_in_cost[mode] == NULL
  	      && ira_may_move_out_cost[mode] == NULL);
-  /* have_regs_of_mode[mode] might be false because it might be
-     E_<mode> (see genmodes) of pseudo with <mode>.  */
+  /* Note that we might be asked about the move costs of modes that
+     cannot be stored in any hard register, for example if an inline
+     asm tries to create a register operand with an impossible mode.
+     We therefore can't assert have_regs_of_mode[mode] here.  */
    for (cl1 = 0; cl1 < N_REG_CLASSES; cl1++)
      for (cl2 = 0; cl2 < N_REG_CLASSES; cl2++)
        {


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