Adjust ira_init_register_move_cost comment

2018-02-05  Richard Sandiford  <richard.sandiford@linaro.org>

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

From-SVN: r257385

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 91969bdfc3f4f42de78e71ea342bc8362fcd29f8..363c61774ff5abfecc2b4aa501d11c5cdf443340 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,7 @@
+2018-02-05  Richard Sandiford  <richard.sandiford@linaro.org>
+
+       * ira.c (ira_init_register_move_cost): Adjust comment.
+
 2018-02-05  Martin Liska  <mliska@suse.cz>
 
        PR gcov-profile/84137

diff --git a/gcc/ira.c b/gcc/ira.c
index 0eafa0ab702bb47fdd1a3fbaa8deb58c588fe145..b7bcc15a15d00feb5b8bb24c2d83b3e116ef523d 100644 (file)
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -1578,8 +1578,10 @@ ira_init_register_move_cost (machine_mode mode)
   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++)
       {