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re PR rtl-optimization/41511 (combine behaves differently with/without -g)

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PR rtl-optimization/41511
	* combine.c (record_value_for_reg): Pass explicit values as argument
	to get_last_value_validate.
	(get_last_value_validate): Document INSN parameter.
	For non-readonly MEMs, assume they might have been modified if INSN
	was in another basic block.
	(get_last_value): Minor reformatting.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r152459
This commit is contained in:
Eric Botcazou 2009-10-05 17:48:09 +00:00 committed by Eric Botcazou
parent 2bd1d2c8d2
commit 9baea66c94
2 changed files with 28 additions and 21 deletions
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11
gcc/ChangeLog
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@ -1,3 +1,14 @@
2009-10-05 Eric Botcazou <ebotcazou@adacore.com>
Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/41511
* combine.c (record_value_for_reg): Pass explicit values as argument
to get_last_value_validate.
(get_last_value_validate): Document INSN parameter.
For non-readonly MEMs, assume they might have been modified if INSN
was in another basic block.
(get_last_value): Minor reformatting.
2009-10-05 Andrew Pinski <andrew_pinski@playstation.sony.com>
PR tree-opt/40992

38
gcc/combine.c
View File

@ -11758,12 +11758,10 @@ record_value_for_reg (rtx reg, rtx insn, rtx value)
case, we must replace it with (clobber (const_int 0)) to prevent
infinite loops. */
rsp = VEC_index (reg_stat_type, reg_stat, regno);
if (value && ! get_last_value_validate (&value, insn,
rsp->last_set_label, 0))
if (value && !get_last_value_validate (&value, insn, label_tick, 0))
{
value = copy_rtx (value);
if (! get_last_value_validate (&value, insn,
rsp->last_set_label, 1))
if (!get_last_value_validate (&value, insn, label_tick, 1))
value = 0;
}
@ -12055,15 +12053,14 @@ check_promoted_subreg (rtx insn, rtx x)
}
}
/* Utility routine for the following function. Verify that all the registers
mentioned in *LOC are valid when *LOC was part of a value set when
label_tick == TICK. Return 0 if some are not.
If REPLACE is nonzero, replace the invalid reference with
(clobber (const_int 0)) and return 1. This replacement is useful because
we often can get useful information about the form of a value (e.g., if
it was produced by a shift that always produces -1 or 0) even though
we don't know exactly what registers it was produced from. */
/* Verify that all the registers and memory references mentioned in *LOC are
still valid. *LOC was part of a value set in INSN when label_tick was
equal to TICK. Return 0 if some are not. If REPLACE is nonzero, replace
the invalid references with (clobber (const_int 0)) and return 1. This
replacement is useful because we often can get useful information about
the form of a value (e.g., if it was produced by a shift that always
produces -1 or 0) even though we don't know exactly what registers it
was produced from. */
static int
get_last_value_validate (rtx *loc, rtx insn, int tick, int replace)
@ -12099,11 +12096,12 @@ get_last_value_validate (rtx *loc, rtx insn, int tick, int replace)
return 1;
}
/* If this is a memory reference, make sure that there were
no stores after it that might have clobbered the value. We don't
have alias info, so we assume any store invalidates it. */
/* If this is a memory reference, make sure that there were no stores after
it that might have clobbered the value. We don't have alias info, so we
assume any store invalidates it. Moreover, we only have local UIDs, so
we also assume that there were stores in the intervening basic blocks. */
else if (MEM_P (x) && !MEM_READONLY_P (x)
&& DF_INSN_LUID (insn) <= mem_last_set)
&& (tick != label_tick || DF_INSN_LUID (insn) <= mem_last_set))
{
if (replace)
*loc = gen_rtx_CLOBBER (GET_MODE (x), const0_rtx);
@ -12213,16 +12211,14 @@ get_last_value (const_rtx x)
return 0;
/* If the value has all its registers valid, return it. */
if (get_last_value_validate (&value, rsp->last_set,
rsp->last_set_label, 0))
if (get_last_value_validate (&value, rsp->last_set, rsp->last_set_label, 0))
return value;
/* Otherwise, make a copy and replace any invalid register with
(clobber (const_int 0)). If that fails for some reason, return 0. */
value = copy_rtx (value);
if (get_last_value_validate (&value, rsp->last_set,
rsp->last_set_label, 1))
if (get_last_value_validate (&value, rsp->last_set, rsp->last_set_label, 1))
return value;
return 0;