The following patch fixes PR55151. The patch affects a sensitive
part of LRA code. So it took some time to find a PR solution. For the
test there were to many reloads into hard registers for an insn and LRA
failed to assign hard registers to all reload pseudos. There is another
more costly alternative for the insn which accepts memory but we need to
put pseudo value into memory for that. LRA did not do it. The patch
adds this possibility. The patch also discourage putting pseudo values
into memory by increasing reject. Without this code, several GCC tests
checking assembler code quality failed. The patch changes SPEC2000 code
for a few tests but overall score is the same.
The patch was successfully bootstrapped and tested on x86/x86-64.
Committed as rev. 193170.
2012-11-05 Vladimir Makarov <vmaka...@redhat.com>
PR rtl-optimization/55151
* lra-constraints.c (process_alt_operands): Permit putting reg
value into memory. Increase reject for this case.
2012-11-05 Vladimir Makarov <vmaka...@redhat.com>
PR rtl-optimization/55151
* gcc.dg/pr55151.c: New test.
Index: lra-constraints.c
===================================================================
--- lra-constraints.c (revision 193169)
+++ lra-constraints.c (working copy)
@@ -1581,7 +1581,9 @@ process_alt_operands (int only_alternati
case TARGET_MEM_CONSTRAINT:
if (MEM_P (op) || spilled_pseudo_p (op))
win = true;
- if (CONST_POOL_OK_P (mode, op))
+ /* We can put constant or pseudo value into memory
+ to satisfy the constraint. */
+ if (CONST_POOL_OK_P (mode, op) || REG_P (op))
badop = false;
constmemok = true;
break;
@@ -1613,7 +1615,10 @@ process_alt_operands (int only_alternati
&& offsettable_nonstrict_memref_p (op))
|| spilled_pseudo_p (op))
win = true;
- if (CONST_POOL_OK_P (mode, op) || MEM_P (op))
+ /* We can put constant or pseudo value into memory
+ or make memory address offsetable to satisfy the
+ constraint. */
+ if (CONST_POOL_OK_P (mode, op) || MEM_P (op) || REG_P (op))
badop = false;
constmemok = true;
offmemok = true;
@@ -1638,6 +1643,7 @@ process_alt_operands (int only_alternati
if (CONST_INT_P (op)
|| (GET_CODE (op) == CONST_DOUBLE && mode == VOIDmode))
break;
+
case 'i':
if (general_constant_p (op))
win = true;
@@ -1702,10 +1708,12 @@ process_alt_operands (int only_alternati
win = true;
/* If we didn't already win, we can reload
- constants via force_const_mem, and other
- MEMs by reloading the address like for
+ constants via force_const_mem or put the
+ pseudo value into memory, or make other
+ memory by reloading the address like for
'o'. */
- if (CONST_POOL_OK_P (mode, op) || MEM_P (op))
+ if (CONST_POOL_OK_P (mode, op)
+ || MEM_P (op) || REG_P (op))
badop = false;
constmemok = true;
offmemok = true;
@@ -1919,6 +1927,13 @@ process_alt_operands (int only_alternati
+= ira_reg_class_max_nregs[this_alternative][mode];
}
+ /* We are trying to spill pseudo into memory. It is
+ usually more costly than moving to a hard register
+ although it might takes the same number of
+ reloads. */
+ if (no_regs_p && REG_P (op))
+ reject++;
+
/* Input reloads can be inherited more often than output
reloads can be removed, so penalize output
reloads. */
Index: testsuite/gcc.dg/pr55151.c
===================================================================
--- testsuite/gcc.dg/pr55151.c (revision 0)
+++ testsuite/gcc.dg/pr55151.c (working copy)
@@ -0,0 +1,13 @@
+/* PR rtl-optimization/55151 */
+/* { dg-do compile } */
+/* { dg-options "-fPIC" } */
+
+int a, b, c, d, e, f, g, h, i, j, k, l;
+void f4 (void)
+{
+ __asm__ volatile ("":[a] "=r,m" (a),[b] "=r,m" (b),[c] "=r,m" (c),
+ [d] "=r,m" (d),[e] "=r,m" (e),[f] "=r,m" (f),
+ [g] "=r,m" (g),[h] "=r,m" (h),[i] "=r,m" (i),
+ [j] "=r,m" (j),[k] "=r,m" (k),[l] "=r,m" (l):"[a],m" (a),
+ "[j],m" (j), "[k],m" (k), "[l],m" (l));
+}
