This is an out-of-bounds access in count_spilled_pseudo: we can enter the
function for a pseudo without hard reg but we immediately use the hard reg
number as an index:
static void
count_spilled_pseudo (int spilled, int spilled_nregs, int reg)
{
int freq = REG_FREQ (reg);
int r = reg_renumber[reg];
int nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (reg)];
The negative R case is only checked a few lines below:
/* Ignore spilled pseudo-registers which can be here only if IRA is
used. */
if ((ira_conflicts_p && r < 0)
|| REGNO_REG_SET_P (&spilled_pseudos, reg)
|| spilled + spilled_nregs <= r || r + nregs <= spilled)
return;
It turns out that count_pseudo contains very similar (and correct) code so the
patch just mimics that code.
Bootstrapped/regtested on x86_64-suse-linux, applied on mainline. Should it be
applied to the release branches as well?
2012-03-26 Eric Botcazou
PR rtl-optimization/52629
* reload1.c (count_pseudo): Short-circuit common case.
(count_spilled_pseudo): Return early for pseudos without hard regs.
Assert that the pseudo has got a hard reg before manipulating it.
--
Eric Botcazou
Index: reload1.c
===
--- reload1.c (revision 185570)
+++ reload1.c (working copy)
@@ -1746,11 +1746,12 @@ count_pseudo (int reg)
int r = reg_renumber[reg];
int nregs;
+ /* Ignore spilled pseudo-registers which can be here only if IRA is used. */
+ if (ira_conflicts_p && r < 0)
+return;
+
if (REGNO_REG_SET_P (&pseudos_counted, reg)
- || REGNO_REG_SET_P (&spilled_pseudos, reg)
- /* Ignore spilled pseudo-registers which can be here only if IRA
- is used. */
- || (ira_conflicts_p && r < 0))
+ || REGNO_REG_SET_P (&spilled_pseudos, reg))
return;
SET_REGNO_REG_SET (&pseudos_counted, reg);
@@ -1827,12 +1828,17 @@ count_spilled_pseudo (int spilled, int s
{
int freq = REG_FREQ (reg);
int r = reg_renumber[reg];
- int nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (reg)];
+ int nregs;
+
+ /* Ignore spilled pseudo-registers which can be here only if IRA is used. */
+ if (ira_conflicts_p && r < 0)
+return;
+
+ gcc_assert (r >= 0);
+
+ nregs = hard_regno_nregs[r][PSEUDO_REGNO_MODE (reg)];
- /* Ignore spilled pseudo-registers which can be here only if IRA is
- used. */
- if ((ira_conflicts_p && r < 0)
- || REGNO_REG_SET_P (&spilled_pseudos, reg)
+ if (REGNO_REG_SET_P (&spilled_pseudos, reg)
|| spilled + spilled_nregs <= r || r + nregs <= spilled)
return;
