The following changes since commit 3c8c36c9087da957f580a9bb5ebf7814a753d1c6:

Merge remote-tracking branch 'remotes/kraxel/tags/ui-20201104-pull-request' into staging (2020-11-04 16:52:17 +0000)

https://github.com/rth7680/qemu.git tags/pull-tcg-20201104

for you to fetch changes up to c56caea3b2a4ef5d760266f554df0d92c5a45f87:

tcg: Revert "tcg/optimize: Flush data at labels not TCG_OPF_BB_END" (2020-11-04 10:35:40 -0800)

Fix assert in set_jmp_reset_offset

Revert cross-branch optimization in tcg/optimize.c.

tcg: Remove assert from set_jmp_reset_offset

tcg: Revert "tcg/optimize: Flush data at labels not TCG_OPF_BB_END"

tcg/optimize.c | 35 +++++++++++++++++------------------

tcg/tcg.c | 9 +++++----

2 files changed, 22 insertions(+), 22 deletions(-)

Since 6e6c4efed99, there has been a more appropriate range check

done later at the end of tcg_gen_code. There, a failing range

check results in a returned error code, which causes the TB to

be restarted at half the size.

Reported-by: Sai Pavan Boddu <saipava@xilinx.com>

Tested-by: Sai Pavan Boddu <sai.pavan.boddu@xilinx.com>

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

tcg/tcg.c | 9 +++++----

1 file changed, 5 insertions(+), 4 deletions(-)

@@ -XXX,XX +XXX,XX @@ static bool tcg_resolve_relocs(TCGContext *s)

static void set_jmp_reset_offset(TCGContext *s, int which)

{

- size_t off = tcg_current_code_size(s);

- s->tb_jmp_reset_offset[which] = off;

- /* Make sure that we didn't overflow the stored offset. */

- assert(s->tb_jmp_reset_offset[which] == off);

+ /*

+ * We will check for overflow at the end of the opcode loop in

+ * tcg_gen_code, where we bound tcg_current_code_size to UINT16_MAX.

+ */

+ s->tb_jmp_reset_offset[which] = tcg_current_code_size(s);

}

#include "tcg-target.c.inc"

2.25.1

This reverts commit cd0372c515c4732d8bd3777cdd995c139c7ed7ea.

The patch is incorrect in that it retains copies between globals and

non-local temps, and non-local temps still die at the end of the BB.

Failing test case for hppa:

    .globl    _start

_start:

    cmpiclr,=    0x24,%r19,%r0

    cmpiclr,<>    0x2f,%r19,%r19

---- 00010057 0001005b

movi_i32 tmp0,$0x24

sub_i32 tmp1,tmp0,r19

mov_i32 tmp2,tmp0

mov_i32 tmp3,r19

movi_i32 tmp1,$0x0

---- 0001005b 0001005f

brcond_i32 tmp2,tmp3,eq,$L1

movi_i32 tmp0,$0x2f

sub_i32 tmp1,tmp0,r19

mov_i32 tmp2,tmp0

mov_i32 tmp3,r19

movi_i32 tmp1,$0x0

mov_i32 r19,tmp1

setcond_i32 psw_n,tmp2,tmp3,ne

set_label $L1

In this case, both copies of "mov_i32 tmp3,r19" are removed. The

second because opt thought it was redundant. The first is removed

later by liveness because tmp3 is known to be dead. This leaves

the setcond_i32 with an uninitialized input.

Revert the entire patch for 5.2, and a proper optimization across

the branch may be considered for the next development cycle.

Reported-by: qemu@igor2.repo.hu

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

tcg/optimize.c | 35 +++++++++++++++++------------------

1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/tcg/optimize.c b/tcg/optimize.c

--- a/tcg/optimize.c

+++ b/tcg/optimize.c

@@ -XXX,XX +XXX,XX @@ void tcg_optimize(TCGContext *s)

}

}

}

- /* fall through */

+ goto do_reset_output;

default:

do_default:

- /*

- * Default case: we know nothing about operation (or were unable

- * to compute the operation result) so no propagation is done.

- */

- for (i = 0; i < nb_oargs; i++) {

- reset_temp(op->args[i]);

- /*

- * Save the corresponding known-zero bits mask for the

- * first output argument (only one supported so far).

- */

- if (i == 0) {

- arg_info(op->args[i])->mask = mask;

+ /* Default case: we know nothing about operation (or were unable

+ to compute the operation result) so no propagation is done.

+ We trash everything if the operation is the end of a basic

+ block, otherwise we only trash the output args. "mask" is

+ the non-zero bits mask for the first output arg. */

+ if (def->flags & TCG_OPF_BB_END) {

+ bitmap_zero(temps_used.l, nb_temps);

+ } else {

+ do_reset_output:

+ for (i = 0; i < nb_oargs; i++) {

+ reset_temp(op->args[i]);

+ /* Save the corresponding known-zero bits mask for the

+ first output argument (only one supported so far). */

+ if (i == 0) {

+ arg_info(op->args[i])->mask = mask;

+ }

}

}

break;

- case INDEX_op_set_label:

- /* Trash everything at the start of a new extended bb. */

- bitmap_zero(temps_used.l, nb_temps);

- break;

}

/* Eliminate duplicate and redundant fence instructions. */

2.25.1