The following patch fixes
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57091
The problem was in choosing alternative with AREG class in an insn and
AREG lives through the insn (until call insn). Reload chooses
alternative with GENERAL_REGS. The problem was solved by tweaking
alternative costs in process_alt_operands. Generally speaking, in such
case LRA could split AREG but because only one insn needs AREG it
decides that is not profitable.
Successfully bootstrapped and tested on x86/x86-64.
Committed as rev. 198503.
2013-05-01 Vladimir Makarov <[email protected]>
PR target/57091
* lra-constraints.c (best_small_class_operands_num): Remove.
(process_alt_operands): Remove small_class_operands_num. Take
small classes operands into losers and only if the operand is not
matched. Modify debugging output.
(curr_insn_transform): Remove best_small_class_operands_num.
Print insn name.
2013-05-01 Vladimir Makarov <[email protected]>
PR target/57091
* gcc.target/i386/pr57091.c: New test.
Index: lra-constraints.c
===================================================================
--- lra-constraints.c (revision 198432)
+++ lra-constraints.c (working copy)
@@ -1048,9 +1048,6 @@ static int goal_alt_number;
/* Number of necessary reloads and overall cost reflecting the
previous value and other unpleasantness of the best alternative. */
static int best_losers, best_overall;
-/* Number of small register classes used for operands of the best
- alternative. */
-static int best_small_class_operands_num;
/* Overall number hard registers used for reloads. For example, on
some targets we need 2 general registers to reload DFmode and only
one floating point register. */
@@ -1326,7 +1323,7 @@ static bool
process_alt_operands (int only_alternative)
{
bool ok_p = false;
- int nop, small_class_operands_num, overall, nalt;
+ int nop, overall, nalt;
int n_alternatives = curr_static_id->n_alternatives;
int n_operands = curr_static_id->n_operands;
/* LOSERS counts the operands that don't fit this alternative and
@@ -1405,6 +1402,7 @@ process_alt_operands (int only_alternati
if (only_alternative >= 0 && nalt != only_alternative)
continue;
+
overall = losers = reject = reload_nregs = reload_sum = 0;
for (nop = 0; nop < n_operands; nop++)
reject += (curr_static_id
@@ -2006,6 +2004,9 @@ process_alt_operands (int only_alternati
if (! no_regs_p)
reload_nregs
+= ira_reg_class_max_nregs[this_alternative][mode];
+
+ if (SMALL_REGISTER_CLASS_P (this_alternative))
+ reject += LRA_LOSER_COST_FACTOR / 2;
}
/* We are trying to spill pseudo into memory. It is
@@ -2033,6 +2034,7 @@ process_alt_operands (int only_alternati
reloads. */
if (!REG_P (op) || curr_static_id->operand[nop].type != OP_IN)
reject++;
+
}
if (early_clobber_p)
@@ -2178,15 +2180,9 @@ process_alt_operands (int only_alternati
overall += LRA_LOSER_COST_FACTOR - 1;
}
}
- small_class_operands_num = 0;
- for (nop = 0; nop < n_operands; nop++)
- small_class_operands_num
- += SMALL_REGISTER_CLASS_P (curr_alt[nop]) ? 1 : 0;
-
if (lra_dump_file != NULL)
- fprintf (lra_dump_file, " alt=%d,overall=%d,losers=%d,"
- "small_class_ops=%d,rld_nregs=%d\n",
- nalt, overall, losers, small_class_operands_num, reload_nregs);
+ fprintf (lra_dump_file, "
alt=%d,overall=%d,losers=%d,rld_nregs=%d\n",
+ nalt, overall, losers, reload_nregs);
/* If this alternative can be made to work by reloading, and it
needs less reloading than the others checked so far, record
@@ -2198,17 +2194,10 @@ process_alt_operands (int only_alternati
|| (best_overall == overall
/* If the cost of the reloads is the same,
prefer alternative which requires minimal
- number of small register classes for the
- operands. This improves chances of reloads
- for insn requiring small register
- classes. */
- && (small_class_operands_num
- < best_small_class_operands_num
- || (small_class_operands_num
- == best_small_class_operands_num
- && (reload_nregs < best_reload_nregs
- || (reload_nregs == best_reload_nregs
- && best_reload_sum < reload_sum))))))))
+ number of reload regs. */
+ && (reload_nregs < best_reload_nregs
+ || (reload_nregs == best_reload_nregs
+ && best_reload_sum < reload_sum))))))
{
for (nop = 0; nop < n_operands; nop++)
{
@@ -2224,7 +2213,6 @@ process_alt_operands (int only_alternati
goal_alt_swapped = curr_swapped;
best_overall = overall;
best_losers = losers;
- best_small_class_operands_num = small_class_operands_num;
best_reload_nregs = reload_nregs;
best_reload_sum = reload_sum;
goal_alt_number = nalt;
@@ -2826,7 +2814,7 @@ curr_insn_transform (void)
operands together against the register constraints. */
best_losers = best_overall = INT_MAX;
- best_small_class_operands_num = best_reload_sum = 0;
+ best_reload_sum = 0;
curr_swapped = false;
goal_alt_swapped = false;
@@ -3033,7 +3021,10 @@ curr_insn_transform (void)
for (; *p != '\0' && *p != ',' && *p != '#'; p++)
fputc (*p, lra_dump_file);
}
- fprintf (lra_dump_file, "\n");
+ if (INSN_CODE (curr_insn) >= 0
+ && (p = get_insn_name (INSN_CODE (curr_insn))) != NULL)
+ fprintf (lra_dump_file, " {%s}", p);
+ fprintf (lra_dump_file, "\n");
}
/* Right now, for any pair of operands I and J that are required to
Index: testsuite/gcc.target/i386/pr57091.c
===================================================================
--- testsuite/gcc.target/i386/pr57091.c (revision 0)
+++ testsuite/gcc.target/i386/pr57091.c (working copy)
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O -mcmodel=large" { target lp64 } } */
+void (*bar)();
+
+void foo (void)
+{
+ bar ();
+}
