patch to add one more criterium for choosing alternatives in LRA

Submitted by Vladimir Makarov on May 2, 2013, 6:56 p.m.

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Message ID 5182B6E9.30802@redhat.com
State New
Headers show

Commit Message

Vladimir Makarov May 2, 2013, 6:56 p.m.
The following patch fixes two GCC testsuite failures on i686 after 
submitting patch to fix PR57091.

The first alternative is always preferable then subsequent ones when all 
costs are the same.  That is how reload works. This checks needs when we 
have commutative operator in an insn.

Committed as rev. 198558.

2013-05-02  Vladimir Makarov  <vmakarov@redhat.com>

         * lra-constraints.c (process_alt_operands): Add checking alt
         number to choose the best alternative.

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Index: lra-constraints.c
===================================================================
--- lra-constraints.c   (revision 198503)
+++ lra-constraints.c   (working copy)
@@ -2197,7 +2197,9 @@  process_alt_operands (int only_alternati
                          number of reload regs.  */
                       && (reload_nregs < best_reload_nregs
                           || (reload_nregs == best_reload_nregs
-                             && best_reload_sum < reload_sum))))))
+                             && (best_reload_sum < reload_sum
+                                 || (best_reload_sum == reload_sum
+                                     && nalt < goal_alt_number))))))))
         {
           for (nop = 0; nop < n_operands; nop++)
             {