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Re: PR 34998: Tracking of subreg liveness in global.c and ra-conflict.c
Kenneth Zadeck <zadeck@naturalbridge.com> writes:
> It looks like iant gave you approval subject to one of the ra
> maintainers saying ok, so check it in.
Thanks. I added the subreg_lowpart check and retested as before.
Here's what I checked in.
(Looking again, we probably handled subreg_lowparts correctly without
the check, since df-scan.c adds a full-register DF_REF_READ_WRITE use
for them. That's not an argument in favour of the original patch;
the new one is more obviously correct. I just thought it might set
minds at rest in case about the strength of the original testing.)
Richard
gcc/
PR rtl-optimization/34998
* global.c (build_insn_chain): Treat non-subreg_lowpart
SUBREGs of pseudos as clobbering all the words covered by the
SUBREG, not just all the bytes.
* ra-conflict.c (clear_reg_in_live): Likewise. Take the
original df_ref rather than an extract parameter.
(global_conflicts): Update call accordingly.
Index: gcc/global.c
===================================================================
--- gcc/global.c 2008-01-29 10:32:52.000000000 +0000
+++ gcc/global.c 2008-01-29 21:05:12.000000000 +0000
@@ -1501,6 +1501,17 @@ build_insn_chain (void)
live_subregs,
live_subregs_used,
regno, reg);
+
+ if (!DF_REF_FLAGS_IS_SET
+ (def, DF_REF_STRICT_LOWER_PART))
+ {
+ /* Expand the range to cover entire words.
+ Bytes added here are "don't care". */
+ start = start / UNITS_PER_WORD * UNITS_PER_WORD;
+ last = ((last + UNITS_PER_WORD - 1)
+ / UNITS_PER_WORD * UNITS_PER_WORD);
+ }
+
/* Ignore the paradoxical bits. */
if ((int)last > live_subregs_used[regno])
last = live_subregs_used[regno];
Index: gcc/ra-conflict.c
===================================================================
--- gcc/ra-conflict.c 2008-01-29 10:32:52.000000000 +0000
+++ gcc/ra-conflict.c 2008-01-29 21:10:39.000000000 +0000
@@ -441,16 +441,14 @@ ra_init_live_subregs (bool init_value,
/* Set REG to be not live in the sets ALLOCNOS_LIVE, LIVE_SUBREGS,
- HARD_REGS_LIVE. If EXTRACT is false, assume that the entire reg is
- set not live even if REG is a subreg. */
+ HARD_REGS_LIVE. DEF is the definition of the register. */
inline static void
clear_reg_in_live (sparseset allocnos_live,
sbitmap *live_subregs,
int *live_subregs_used,
HARD_REG_SET *hard_regs_live,
- rtx reg,
- bool extract)
+ rtx reg, struct df_ref *def)
{
unsigned int regno = (GET_CODE (reg) == SUBREG)
? REGNO (SUBREG_REG (reg)): REGNO (reg);
@@ -458,8 +456,8 @@ clear_reg_in_live (sparseset allocnos_li
if (allocnum >= 0)
{
- if ((GET_CODE (reg) == SUBREG) && !extract)
-
+ if (GET_CODE (reg) == SUBREG
+ && !DF_REF_FLAGS_IS_SET (def, DF_REF_EXTRACT))
{
unsigned int start = SUBREG_BYTE (reg);
unsigned int last = start + GET_MODE_SIZE (GET_MODE (reg));
@@ -467,6 +465,15 @@ clear_reg_in_live (sparseset allocnos_li
ra_init_live_subregs (sparseset_bit_p (allocnos_live, allocnum),
live_subregs, live_subregs_used, allocnum, reg);
+ if (!DF_REF_FLAGS_IS_SET (def, DF_REF_STRICT_LOWER_PART))
+ {
+ /* Expand the range to cover entire words.
+ Bytes added here are "don't care". */
+ start = start / UNITS_PER_WORD * UNITS_PER_WORD;
+ last = ((last + UNITS_PER_WORD - 1)
+ / UNITS_PER_WORD * UNITS_PER_WORD);
+ }
+
/* Ignore the paradoxical bits. */
if ((int)last > live_subregs_used[allocnum])
last = live_subregs_used[allocnum];
@@ -503,7 +510,8 @@ clear_reg_in_live (sparseset allocnos_li
if (! fixed_regs[regno])
{
unsigned int start = regno;
- if ((GET_CODE (reg) == SUBREG) && !extract)
+ if (GET_CODE (reg) == SUBREG
+ && !DF_REF_FLAGS_IS_SET (def, DF_REF_EXTRACT))
{
unsigned int last;
start += SUBREG_BYTE (reg);
@@ -890,8 +898,7 @@ global_conflicts (void)
rtx reg = DF_REF_REG (def);
clear_reg_in_live (allocnos_live, live_subregs, live_subregs_used,
- &hard_regs_live, reg,
- DF_REF_FLAGS_IS_SET (def, DF_REF_EXTRACT));
+ &hard_regs_live, reg, def);
if (dump_file)
dump_ref (dump_file, " clearing def", "\n",
reg, DF_REF_REGNO (def), live_subregs, live_subregs_used);