re PR fortran/54107 ([F03] Memory hog with abstract interface)

[gcc.git] / gcc / lra-lives.c

diff --git a/gcc/lra-lives.c b/gcc/lra-lives.c
index f2dc359c18bc3a32bca601dd32ca4e9014b48fda..09db1a4122be102106e315130a90b396ab12f189 100644 (file)
--- a/gcc/lra-lives.c
+++ b/gcc/lra-lives.c
@@ -1,6 +1,5 @@
 /* Build live ranges for pseudos.
-   Copyright (C) 2010, 2011, 2012
-   Free Software Foundation, Inc.
+   Copyright (C) 2010-2013 Free Software Foundation, Inc.
    Contributed by Vladimir Makarov <vmakarov@redhat.com>.
 
 This file is part of GCC.
@@ -915,6 +914,7 @@ lra_create_live_ranges (bool all_p)
   basic_block bb;
   int i, hard_regno, max_regno = max_reg_num ();
   int curr_point;
+  bool have_referenced_pseudos = false;
 
   timevar_push (TV_LRA_CREATE_LIVE_RANGES);
 
@@ -935,6 +935,10 @@ lra_create_live_ranges (bool all_p)
 #ifdef STACK_REGS
       lra_reg_info[i].no_stack_p = false;
 #endif
+      /* The biggest mode is already set but its value might be to
+        conservative because of recent transformation.  Here in this
+        file we recalculate it again as it costs practically
+        nothing.  */
       if (regno_reg_rtx[i] != NULL_RTX)
        lra_reg_info[i].biggest_mode = GET_MODE (regno_reg_rtx[i]);
       else
@@ -943,10 +947,24 @@ lra_create_live_ranges (bool all_p)
       lra_reg_info[i].call_p = false;
 #endif
       if (i >= FIRST_PSEUDO_REGISTER
-         && lra_reg_info[i].nrefs != 0 && (hard_regno = reg_renumber[i]) >= 0)
-       lra_hard_reg_usage[hard_regno] += lra_reg_info[i].freq;
+         && lra_reg_info[i].nrefs != 0)
+       {
+         if ((hard_regno = reg_renumber[i]) >= 0)
+           lra_hard_reg_usage[hard_regno] += lra_reg_info[i].freq;
+         have_referenced_pseudos = true;
+       }
     }
   lra_free_copies ();
+ 
+  /* Under some circumstances, we can have functions without pseudo
+     registers.  For such functions, lra_live_max_point will be 0,
+     see e.g. PR55604, and there's nothing more to do for us here.  */
+  if (! have_referenced_pseudos)
+    {
+      timevar_pop (TV_LRA_CREATE_LIVE_RANGES);
+      return;
+    }
+
   pseudos_live = sparseset_alloc (max_regno);
   pseudos_live_through_calls = sparseset_alloc (max_regno);
   pseudos_live_through_setjumps = sparseset_alloc (max_regno);
@@ -969,6 +987,7 @@ lra_create_live_ranges (bool all_p)
     }
   free (post_order_rev_cfg);
   lra_live_max_point = curr_point;
+  gcc_checking_assert (lra_live_max_point > 0);
   if (lra_dump_file != NULL)
     print_live_ranges (lra_dump_file);
   /* Clean up. */