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Commit 73dd3123 by Eric Botcazou Committed by Eric Botcazou
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re PR rtl-optimization/56178 (Miscompilation of Ada front-end with profiled bootstrap) 

	PR rtl-optimization/56178
	* cse.c (cse_insn): Do not create a REG_EQUAL note if the source is a
	SUBREG of a register.  Tidy up related block of code.
	* fwprop.c (forward_propagate_and_simplify): Do not create a REG_EQUAL
	note if the source is a register or a SUBREG of a register.

From-SVN: r195841
parent e3936f47
Showing with 38 additions and 24 deletions
gcc/ChangeLog
2013-02-07 Eric Botcazou <ebotcazou@adacore.com>
PR rtl-optimization/56178
* cse.c (cse_insn): Do not create a REG_EQUAL note if the source is a
SUBREG of a register. Tidy up related block of code.
* fwprop.c (forward_propagate_and_simplify): Do not create a REG_EQUAL
note if the source is a register or a SUBREG of a register.
2013-02-07 Jakub Jelinek <jakub@redhat.com>
PR target/56228
......
gcc/cse.c
......@@ -5311,33 +5311,33 @@ cse_insn (rtx insn)
}
/* If this is a single SET, we are setting a register, and we have an
equivalent constant, we want to add a REG_NOTE. We don't want
to write a REG_EQUAL note for a constant pseudo since verifying that
that pseudo hasn't been eliminated is a pain. Such a note also
won't help anything.
equivalent constant, we want to add a REG_EQUAL note if the constant
is different from the source. We don't want to do it for a constant
pseudo since verifying that this pseudo hasn't been eliminated is a
pain; moreover such a note won't help anything.
Avoid a REG_EQUAL note for (CONST (MINUS (LABEL_REF) (LABEL_REF)))
which can be created for a reference to a compile time computable
entry in a jump table. */
if (n_sets == 1 && src_const && REG_P (dest)
if (n_sets == 1
&& REG_P (dest)
&& src_const
&& !REG_P (src_const)
&& ! (GET_CODE (src_const) == CONST
&& GET_CODE (XEXP (src_const, 0)) == MINUS
&& GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF
&& GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF))
&& !(GET_CODE (src_const) == SUBREG
&& REG_P (SUBREG_REG (src_const)))
&& !(GET_CODE (src_const) == CONST
&& GET_CODE (XEXP (src_const, 0)) == MINUS
&& GET_CODE (XEXP (XEXP (src_const, 0), 0)) == LABEL_REF
&& GET_CODE (XEXP (XEXP (src_const, 0), 1)) == LABEL_REF)
&& !rtx_equal_p (src, src_const))
{
/* We only want a REG_EQUAL note if src_const != src. */
if (! rtx_equal_p (src, src_const))
{
/* Make sure that the rtx is not shared. */
src_const = copy_rtx (src_const);
/* Make sure that the rtx is not shared. */
src_const = copy_rtx (src_const);
/* Record the actual constant value in a REG_EQUAL note,
making a new one if one does not already exist. */
set_unique_reg_note (insn, REG_EQUAL, src_const);
df_notes_rescan (insn);
}
/* Record the actual constant value in a REG_EQUAL note,
making a new one if one does not already exist. */
set_unique_reg_note (insn, REG_EQUAL, src_const);
df_notes_rescan (insn);
}
/* Now deal with the destination. */
......
gcc/fwprop.c
......@@ -1316,10 +1316,16 @@ forward_propagate_and_simplify (df_ref use, rtx def_insn, rtx def_set)
separately try plugging the definition in the note and simplifying.
And only install a REQ_EQUAL note when the destination is a REG
that isn't mentioned in USE_SET, as the note would be invalid
otherwise. */
set_reg_equal = (note == NULL_RTX && REG_P (SET_DEST (use_set))
&& ! reg_mentioned_p (SET_DEST (use_set),
SET_SRC (use_set)));
otherwise. We also don't want to install a note if we are merely
propagating a pseudo since verifying that this pseudo isn't dead
is a pain; moreover such a note won't help anything. */
set_reg_equal = (note == NULL_RTX
&& REG_P (SET_DEST (use_set))
&& !REG_P (src)
&& !(GET_CODE (src) == SUBREG
&& REG_P (SUBREG_REG (src)))
&& !reg_mentioned_p (SET_DEST (use_set),
SET_SRC (use_set)));
}
if (GET_MODE (*loc) == VOIDmode)
......
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