From: Alexandre Oliva <aoliva@redhat.com>
To: Alan Lawrence <alan.lawrence@arm.com>
Cc: "gcc-patches\@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
Marcus Shawcroft <Marcus.Shawcroft@arm.com>,
James Greenhalgh <james.greenhalgh@arm.com>
Subject: Re: [PR64164] drop copyrename, integrate into expand
Date: Tue, 10 Nov 2015 22:59:00 -0000 [thread overview]
Message-ID: <or4mgtmpgs.fsf@livre.home> (raw)
In-Reply-To: <56420DC4.3070407@arm.com> (Alan Lawrence's message of "Tue, 10 Nov 2015 15:31:16 +0000")
On Nov 10, 2015, Alan Lawrence <alan.lawrence@arm.com> wrote:
> FAIL: gcc.target/aarch64/aapcs64/func-ret-4.c execution, -O2
Ugh, sorry. I even checked that testcase by hand before submitting the
patch, because I knew it took the paths I was changing, but I didn't
realize the stack store and load would amount to shifts when the stack
slot was bypassed.
With the following patch, we get a lsr and a ubfx, without the sp
adjustments. Please let me know if it causes any further problems. So
far, I've tested it on x86_64-linux-gnu, i686-linux-gnu, and
ppc64le-linux-gnu; the ppc64-linux-gnu test run is running slower and
probably won't be done before I call it a day, but I wanted to give you
something before taking off for the day.
Is this ok to install if ppc64-linux-gnu also regstraps successfully?
[PR67753] adjust for padding when bypassing memory in assign_parm_setup_block
From: Alexandre Oliva <aoliva@redhat.com>
Storing a register in memory as a full word and then accessing the
same memory address under a smaller-than-word mode amounts to
right-shifting of the register word on big endian machines. So, if
BLOCK_REG_PADDING chooses upward padding for BYTES_BIG_ENDIAN, and
we're copying from the entry_parm REG directly to a pseudo, bypassing
any stack slot, perform the shifting explicitly.
This fixes the miscompile of function_return_val_10 in
gcc.target/aarch64/aapcs64/func-ret-4.c for target aarch64_be-elf
introduced in the first patch for 67753.
for gcc/ChangeLog
PR rtl-optimization/67753
PR rtl-optimization/64164
* function.c (assign_parm_setup_block): Right-shift
upward-padded big-endian args when bypassing the stack slot.
---
gcc/function.c | 44 +++++++++++++++++++++++++++++++++++++++++---
1 file changed, 41 insertions(+), 3 deletions(-)
diff --git a/gcc/function.c b/gcc/function.c
index a637cb3..1ee092c 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -3002,6 +3002,38 @@ assign_parm_setup_block (struct assign_parm_data_all *all,
emit_move_insn (change_address (mem, mode, 0), reg);
}
+#ifdef BLOCK_REG_PADDING
+ /* Storing the register in memory as a full word, as
+ move_block_from_reg below would do, and then using the
+ MEM in a smaller mode, has the effect of shifting right
+ if BYTES_BIG_ENDIAN. If we're bypassing memory, the
+ shifting must be explicit. */
+ else if (!MEM_P (mem))
+ {
+ rtx x;
+
+ /* If the assert below fails, we should have taken the
+ mode != BLKmode path above, unless we have downward
+ padding of smaller-than-word arguments on a machine
+ with little-endian bytes, which would likely require
+ additional changes to work correctly. */
+ gcc_checking_assert (BYTES_BIG_ENDIAN
+ && (BLOCK_REG_PADDING (mode,
+ data->passed_type, 1)
+ == upward));
+
+ int by = (UNITS_PER_WORD - size) * BITS_PER_UNIT;
+
+ x = gen_rtx_REG (word_mode, REGNO (entry_parm));
+ x = expand_shift (RSHIFT_EXPR, word_mode, x, by,
+ NULL_RTX, 1);
+ x = force_reg (word_mode, x);
+ x = gen_lowpart_SUBREG (GET_MODE (mem), x);
+
+ emit_move_insn (mem, x);
+ }
+#endif
+
/* Blocks smaller than a word on a BYTES_BIG_ENDIAN
machine must be aligned to the left before storing
to memory. Note that the previous test doesn't
@@ -3023,14 +3055,20 @@ assign_parm_setup_block (struct assign_parm_data_all *all,
tem = change_address (mem, word_mode, 0);
emit_move_insn (tem, x);
}
- else if (!MEM_P (mem))
- emit_move_insn (mem, entry_parm);
else
move_block_from_reg (REGNO (entry_parm), mem,
size_stored / UNITS_PER_WORD);
}
else if (!MEM_P (mem))
- emit_move_insn (mem, entry_parm);
+ {
+ gcc_checking_assert (size > UNITS_PER_WORD);
+#ifdef BLOCK_REG_PADDING
+ gcc_checking_assert (BLOCK_REG_PADDING (GET_MODE (mem),
+ data->passed_type, 0)
+ == upward);
+#endif
+ emit_move_insn (mem, entry_parm);
+ }
else
move_block_from_reg (REGNO (entry_parm), mem,
size_stored / UNITS_PER_WORD);
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
next prev parent reply other threads:[~2015-11-10 22:59 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-27 18:04 Alexandre Oliva
2015-03-27 18:11 ` Alexandre Oliva
2015-03-28 19:22 ` Alexandre Oliva
2015-03-31 5:11 ` Jeff Law
2015-04-03 13:17 ` Alexandre Oliva
2015-04-06 16:08 ` Jeff Law
2015-04-24 1:56 ` Alexandre Oliva
2015-04-27 11:39 ` Richard Biener
2015-06-06 5:12 ` Alexandre Oliva
2015-06-08 8:16 ` Richard Biener
2015-06-09 8:58 ` Christophe Lyon
2015-06-10 0:28 ` Alexandre Oliva
2015-06-10 13:36 ` Richard Biener
2015-07-16 7:58 ` Alexandre Oliva
2015-07-16 8:50 ` Richard Biener
2015-07-16 21:33 ` Alexandre Oliva
2015-07-18 8:26 ` Alexandre Oliva
2015-07-21 13:25 ` Richard Biener
2015-07-22 17:13 ` Alexandre Oliva
2015-07-22 17:43 ` Alexandre Oliva
2015-07-23 11:04 ` Richard Biener
2015-07-23 15:42 ` Alexandre Oliva
2015-07-23 20:35 ` Segher Boessenkool
2015-07-23 21:24 ` H.J. Lu
2015-07-23 22:11 ` H.J. Lu
2015-07-24 1:31 ` David Edelsohn
2015-07-24 5:08 ` H.J. Lu
2015-07-24 9:26 ` Richard Biener
2015-07-24 12:50 ` H.J. Lu
2015-07-24 20:20 ` Alexandre Oliva
2015-07-25 2:37 ` David Edelsohn
2015-07-27 22:16 ` Alexandre Oliva
2015-07-27 22:31 ` H.J. Lu
2015-07-24 18:51 ` Alexandre Oliva
2015-07-24 19:12 ` H.J. Lu
2015-07-24 19:31 ` David Edelsohn
2015-07-24 20:43 ` Alexandre Oliva
2015-07-24 20:47 ` Alexandre Oliva
2015-07-24 21:53 ` H.J. Lu
2015-07-25 7:17 ` Richard Biener
2015-07-29 20:52 ` Alexandre Oliva
2015-07-29 21:06 ` H.J. Lu
2015-07-30 17:47 ` H.J. Lu
2015-08-03 23:46 ` Alexandre Oliva
2015-08-04 9:48 ` Richard Biener
2015-08-05 0:39 ` Alexandre Oliva
2015-08-05 9:14 ` Richard Biener
2015-08-05 23:03 ` Alexandre Oliva
2015-08-10 8:24 ` James Greenhalgh
2015-08-10 15:14 ` Jeff Law
2015-08-11 4:53 ` Patrick Marlier
2015-08-14 19:03 ` Alexandre Oliva
2015-08-15 8:57 ` Andreas Schwab
2015-08-16 13:00 ` Alexandre Oliva
[not found] ` <m2k2sv8s21.fsf@linux-m68k.org>
2015-08-17 5:05 ` Alexandre Oliva
2015-08-17 9:29 ` Kyrill Tkachov
2015-08-17 16:23 ` Andrew Pinski
2015-08-18 16:18 ` Kyrill Tkachov
2015-08-16 16:42 ` Andreas Schwab
2015-08-17 2:57 ` Alexandre Oliva
2015-08-17 8:23 ` Andreas Schwab
2015-08-17 9:21 ` Andreas Schwab
2015-08-17 11:58 ` Alexandre Oliva
2015-08-17 7:48 ` Christophe Lyon
2015-08-17 12:43 ` Alexandre Oliva
2015-08-17 13:39 ` Christophe Lyon
2015-08-18 6:53 ` Alexandre Oliva
2015-08-19 6:50 ` Alexandre Oliva
2015-08-19 10:17 ` Richard Biener
2015-08-19 13:35 ` Andreas Schwab
2015-08-19 13:45 ` Andreas Schwab
2015-08-19 17:48 ` Alexandre Oliva
2015-08-20 1:44 ` Alexandre Oliva
2015-08-20 17:03 ` Jeff Law
2015-08-21 7:57 ` Alexandre Oliva
2015-08-21 8:38 ` Richard Biener
2015-08-21 12:17 ` Andreas Schwab
2015-08-21 8:11 ` Alexandre Oliva
2015-08-21 8:37 ` Richard Biener
2015-09-02 17:09 ` Alan Lawrence
2015-09-02 22:34 ` Alexandre Oliva
2015-09-03 10:58 ` Alan Lawrence
2015-09-18 15:49 ` Alan Lawrence
2015-09-23 20:44 ` Alexandre Oliva
2015-09-25 11:39 ` Richard Biener
2015-10-09 5:26 ` [PR67828] don't unswitch loops on undefined SSA values (was: Re: [PR64164] drop copyrename, integrate into expand) Alexandre Oliva
2015-10-09 9:35 ` Richard Biener
2015-10-09 5:36 ` [PR67766] reorder return value copying from PARALLELs and CONCATs " Alexandre Oliva
2015-10-09 7:33 ` [PR67891] drop is_gimple_reg test from set_parm_rtl (was: [PR67766] reorder return value copying from PARALLELs and CONCATs) Alexandre Oliva
2015-10-09 9:40 ` Richard Biener
2015-10-10 13:20 ` [PR67891] drop is_gimple_reg test from set_parm_rtl Alexandre Oliva
2015-10-12 10:22 ` Richard Biener
2015-10-14 3:25 ` Alexandre Oliva
2015-10-14 9:28 ` Richard Biener
2015-11-03 1:11 ` Alexandre Oliva
2015-11-03 3:14 ` Jeff Law
2015-11-03 4:29 ` Alexandre Oliva
2022-10-17 12:08 ` Tag 'gcc/gimple-expr.cc:mark_addressable_2' as 'static' (was: [PR67891] drop is_gimple_reg test from set_parm_rtl) Thomas Schwinge
2015-10-09 9:36 ` [PR67766] reorder return value copying from PARALLELs and CONCATs (was: Re: [PR64164] drop copyrename, integrate into expand) Richard Biener
2015-09-29 11:31 ` [PR64164] drop copyrename, integrate into expand Szabolcs Nagy
2015-10-07 22:37 ` Alexandre Oliva
2015-10-08 10:00 ` Richard Biener
2015-10-09 21:10 ` Jeff Law
2015-11-05 5:09 ` Alexandre Oliva
2015-11-05 13:44 ` Richard Biener
2015-11-10 15:31 ` Alan Lawrence
2015-11-10 22:59 ` Alexandre Oliva [this message]
2015-11-10 23:43 ` Jeff Law
2015-11-11 18:10 ` Alexandre Oliva
2015-11-13 6:33 ` Jeff Law
2015-11-17 0:07 ` Alexandre Oliva
2015-11-24 5:41 ` Jeff Law
2015-07-24 18:21 ` Alexandre Oliva
2015-07-29 20:32 ` Alexandre Oliva
2015-04-29 3:51 ` Jeff Law
2015-03-31 6:55 ` Steven Bosscher
2015-03-31 13:30 ` Richard Biener
2015-03-31 14:06 ` Richard Biener
2015-04-03 13:30 ` Alexandre Oliva
2015-04-06 15:57 ` Jeff Law
2015-12-04 12:45 ` Dominik Vogt
2015-06-09 16:19 David Edelsohn
2015-06-09 18:36 ` Alexandre Oliva
2015-06-09 20:24 ` Alexandre Oliva
2015-06-09 20:59 ` Jakub Jelinek
2015-06-09 21:36 ` Eric Botcazou
2015-06-09 21:38 ` David Edelsohn
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