Commit graph

280 commits

Author SHA1 Message Date
Emilio G. Cota b1311c4acf tcg: define tcg_init_ctx and make tcg_ctx a pointer
Groundwork for supporting multiple TCG contexts.

The core of this patch is this change to tcg/tcg.h:

> -extern TCGContext tcg_ctx;
> +extern TCGContext tcg_init_ctx;
> +extern TCGContext *tcg_ctx;

Note that for now we set *tcg_ctx to whatever TCGContext is passed
to tcg_context_init -- in this case &tcg_init_ctx.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 13:53:42 -07:00
Richard Henderson dc41aa7d34 tcg: Remove GET_TCGV_* and MAKE_TCGV_*
The GET and MAKE functions weren't really specific enough.
We now have a full complement of functions that convert exactly
between temporaries, arguments, tcgv pointers, and indices.

The target/sparc change is also a bug fix, which would have affected
a host that defines TCG_TARGET_HAS_extr[lh]_i64_i32, i.e. MIPS64.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 21:49:30 +02:00
Richard Henderson 085272b35e tcg: Introduce temp_tcgv_{i32,i64,ptr}
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 21:48:59 +02:00
Richard Henderson ae8b75dc6e tcg: Introduce tcgv_{i32,i64,ptr}_{arg,temp}
Transform TCGv_* to an "argument" or a temporary.
For now, an argument is simply the temporary index.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 21:47:46 +02:00
Richard Henderson 960c50e077 tcg: Push tcg_ctx into tcg_gen_callN
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-24 21:47:29 +02:00
Richard Henderson 2272e4a791 tcg: Change temp_allocate_frame arg to TCGTemp
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:44:52 +02:00
Richard Henderson ac3b88911e tcg: Avoid loops against variable bounds
Copy s->nb_globals or s->nb_temps to a local variable for the purposes
of iteration.  This should allow the compiler to use low-overhead
looping constructs on some hosts.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:44:34 +02:00
Richard Henderson b83eabeac0 tcg: Use per-temp state data in liveness
This avoids having to allocate external memory for each temporary.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:44:34 +02:00
Richard Henderson 1807f4c400 tcg: Introduce temp_arg, export temp_idx
At the same time, drop the TCGContext argument and use tcg_ctx instead.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:44:12 +02:00
Richard Henderson fa477d2547 tcg: Add temp_global bit to TCGTemp
This avoids needing to test the index of a temp against nb_globals.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:43:50 +02:00
Richard Henderson 434391390b tcg: Introduce arg_temp
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:43:36 +02:00
Richard Henderson dd18629201 tcg: Propagate TCGOp down to allocators
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:34:47 +02:00
Richard Henderson efee3746fa tcg: Propagate args to op->args in tcg.c
Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:34:47 +02:00
Richard Henderson 75e8b9b7aa tcg: Merge opcode arguments into TCGOp
Rather than have a separate buffer of 10*max_ops entries,
give each opcode 10 entries.  The result is actually a bit
smaller and should have slightly more cache locality.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-10-24 21:34:47 +02:00
Emilio G. Cota a505785cd2 tcg: define TCG_HIGHWATER
Will come in handy very soon.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-10 09:45:00 -07:00
Emilio G. Cota 619205fd1f tcg: take .helpers out of TCGContext
Groundwork for supporting multiple TCG contexts.

The hash table becomes read-only after it is filled in,
so we can save space by keeping just a global pointer to it.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-10 07:37:10 -07:00
Emilio G. Cota e7e168f413 exec-all: extract tb->tc_* into a separate struct tc_tb
In preparation for adding tc.size to be able to keep track of
TB's using the binary search tree implementation from glib.

Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-10 07:37:10 -07:00
Richard Henderson 07ddf036fa tcg: Remove tcg_regset_{or,and,andnot,not}
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00
Richard Henderson d21369f5fb tcg: Remove tcg_regset_set
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00
Richard Henderson ccb1bb66ea tcg: Remove tcg_regset_clear
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00
Richard Henderson be0f34b584 tcg: Add tcg_op_supported
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-17 06:52:19 -07:00
Richard Henderson 57a269469d tcg: Infrastructure for managing constant pools
A new shared header tcg-pool.inc.c adds new_pool_label,
for registering a tcg_target_ulong to be emitted after
the generated code, plus relocation data to install a
pointer to the data.

A new pointer is added to the TCGContext, so that we
dump the constant pool as data, not code.

Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-09-07 11:57:35 -07:00
Richard Henderson 659ef5cbb8 tcg: Rearrange ldst label tracking
Dispense with TCGBackendData, as it has never been used for more than
holding a single pointer.  Use a define in the cpu/tcg-target.h to
signal requirement for TCGLabelQemuLdst, so that we can drop the no-op
tcg-be-null.h stubs.  Rename tcg-be-ldst.h to tcg-ldst.inc.c.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-09-07 11:57:35 -07:00
Emilio G. Cota 6e3b2bfd6a tcg: allocate TB structs before the corresponding translated code
Allocating an arbitrarily-sized array of tbs results in either
(a) a lot of memory wasted or (b) unnecessary flushes of the code
cache when we run out of TB structs in the array.

An obvious solution would be to just malloc a TB struct when needed,
and keep the TB array as an array of pointers (recall that tb_find_pc()
needs the TB array to run in O(log n)).

Perhaps a better solution, which is implemented in this patch, is to
allocate TB's right before the translated code they describe. This
results in some memory waste due to padding to have code and TBs in
separate cache lines--for instance, I measured 4.7% of padding in the
used portion of code_gen_buffer when booting aarch64 Linux on a
host with 64-byte cache lines. However, it can allow for optimizations
in some host architectures, since TCG backends could safely assume that
the TB and the corresponding translated code are very close to each
other in memory. See this message by rth for a detailed explanation:

  https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg05172.html
  Subject: Re: GSoC 2017 Proposal: TCG performance enhancements
  Message-ID: <1e67644b-4b30-887e-d329-1848e94c9484@twiddle.net>

Suggested-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1496790745-314-3-git-send-email-cota@braap.org>
[rth: Simplify the arithmetic in tcg_tb_alloc]
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-06-19 11:10:59 -07:00
Emilio G. Cota cedbcb0152 tcg: Introduce goto_ptr opcode and tcg_gen_lookup_and_goto_ptr
Instead of exporting goto_ptr directly to TCG frontends, export
tcg_gen_lookup_and_goto_ptr(), which calls goto_ptr with the pointer
returned by the lookup_tb_ptr() helper. This is the only use case
we have for goto_ptr and lookup_tb_ptr, so having this function is
very convenient. Furthermore, it trivially allows us to avoid calling
the lookup helper if goto_ptr is not implemented by the backend.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1493263764-18657-2-git-send-email-cota@braap.org>
Message-Id: <1493263764-18657-3-git-send-email-cota@braap.org>
Message-Id: <1493263764-18657-4-git-send-email-cota@braap.org>
Message-Id: <1493263764-18657-5-git-send-email-cota@braap.org>
[rth: Squashed 4 related commits.]
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-06-05 09:25:42 -07:00
Richard Henderson 17280ff4a5 tcg: Allow an operand to be matching or a constant
This allows an output operand to match an input operand
only when the input operand needs a register.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-01-10 08:06:11 -08:00
Richard Henderson 069ea736b5 tcg: Pass the opcode width to target_parse_constraint
This will let us choose how to interpret a given constraint
depending on whether the opcode is 32- or 64-bit.  Which will
let us share more constraint combinations between opcodes.

At the same time, change the interface to return the advanced
pointer instead of passing it in/out by reference.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-01-10 08:06:11 -08:00
Richard Henderson f69d277ece tcg: Transition flat op_defs array to a target callback
This will allow the target to tailor the constraints to the
auto-detected ISA extensions.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-01-10 08:06:11 -08:00
Richard Henderson 82790a8709 tcg: Add markup for output requires new register
This is the same concept as, and same markup as, the
early clobber markup in gcc.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-01-10 08:06:11 -08:00
Richard Henderson 1ee73216f4 log: Add locking to large logging blocks
Reuse the existing locking provided by stdio to keep in_asm, cpu,
op, op_opt, op_ind, and out_asm as contiguous blocks.

While it isn't possible to interleave e.g. in_asm or op_opt logs
because of the TB lock protecting all code generation, it is
possible to interleave cpu logs, or to interleave a cpu dump with
an out_asm dump.

For mingw32, we appear to have no viable solution for this.  The locking
functions are not properly exported from the system runtime library.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-11-01 10:29:03 -06:00
Paolo Bonzini 0fe4fca4e1 tcg: try sti when moving a constant into a dead memory temp
This comes from free from unifying tcg_reg_alloc_mov and
tcg_reg_alloc_movi's handling of TEMP_VAL_CONST.  It triggers
often on moves to cc_dst, such as the following translation
of "sub $0x3c,%esp":

  before:                          after:
  subl   $0x3c,%ebp                subl   $0x3c,%ebp
  movl   %ebp,0x10(%r14)           movl   %ebp,0x10(%r14)
  movl   $0x3c,%ebx                movl   $0x3c,0x2c(%r14)
  movl   %ebx,0x2c(%r14)

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <1473945360-13663-1-git-send-email-pbonzini@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-10-24 15:27:19 +02:00
Thomas Huth 347519eb9d tcg: Remove duplicate header includes
host-utils.h and timer.h are included twice in tcg.c.
One time should be enough.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2016-09-15 15:32:22 +03:00
Richard Henderson 5a18407f55 tcg: Lower indirect registers in a separate pass
Rather than rely on recursion during the middle of register allocation,
lower indirect registers to loads and stores off the indirect base into
plain temps.

For an x86_64 host, with sufficient registers, this results in identical
code, modulo the actual register assignments.

For an i686 host, with insufficient registers, this means that temps can
be (temporarily) spilled to the stack in order to satisfy an allocation.
This as opposed to the possibility of not being able to spill, to allocate
a register for the indirect base, in order to perform a spill.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:40 +05:30
Richard Henderson c0ef05b5e6 tcg: Require liveness analysis
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:40 +05:30
Richard Henderson bdfb460ef7 tcg: Include liveness info in the dumps
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:40 +05:30
Richard Henderson c70fbf0a99 tcg: Compress dead_temps and mem_temps into a single array
We only need two bits per temporary.  Fold the two bytes into one,
and reduce the memory and cachelines required during compilation.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:40 +05:30
Richard Henderson bee158cb4d tcg: Fold life data into TCGOp
Reduce the size of other bitfields to make room.
This reduces the cache footprint of compilation.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:40 +05:30
Richard Henderson dcb8e75870 tcg: Reorg TCGOp chaining
Instead of using -1 as end of chain, use 0, and link through the 0
entry as a fully circular double-linked list.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:18 +05:30
Richard Henderson a1b3c48d2b tcg: Compress liveness data to 16 bits
This reduces both memory usage and per-insn cacheline usage
during code generation.

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-08-05 21:44:17 +05:30
Sergey Sorokin 1f00b27f17 tcg: Improve the alignment check infrastructure
Some architectures (e.g. ARMv8) need the address which is aligned
to a size more than the size of the memory access.
To support such check it's enough the current costless alignment
check implementation in QEMU, but we need to support
an alignment size specifying.

Signed-off-by: Sergey Sorokin <afarallax@yandex.ru>
Message-Id: <1466705806-679898-1-git-send-email-afarallax@yandex.ru>
Signed-off-by: Richard Henderson <rth@twiddle.net>
[rth: Assert in tcg_canonicalize_memop.  Leave get_alignment_bits
available for, though unused by, user-mode.  Retain logging difference
based on ALIGNED_ONLY.]
2016-07-05 20:50:13 -07:00
Richard Henderson 59d7c14eef tcg: Optimize spills of constants
While we can store constants via constrants on INDEX_op_st_i32 et al,
we weren't able to spill constants to backing store.

Add a new backend interface, tcg_out_sti, which may store the constant
(and is allowed to fail).  Rearrange the temp_* helpers so that we only
attempt to directly store a constant when the temp is becoming dead/free.

Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-07-05 20:50:13 -07:00
Richard Henderson 120c1084ed tcg: Fix name for high-half register
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-07-05 20:50:12 -07:00
Paolo Bonzini 63c915526d cpu: move exec-all.h inclusion out of cpu.h
exec-all.h contains TCG-specific definitions.  It is not needed outside
TCG-specific files such as translate.c, exec.c or *helper.c.

One generic function had snuck into include/exec/exec-all.h; move it to
include/qom/cpu.h.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-05-19 16:42:29 +02:00
Aurelien Jarno 8d8fdbae01 tcg: check for CONFIG_DEBUG_TCG instead of NDEBUG
Check for CONFIG_DEBUG_TCG instead of NDEBUG, drop now useless code.

Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1461228530-14852-2-git-send-email-aurelien@aurel32.net
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-04-21 15:43:20 +01:00
Aurelien Jarno eabb7b91b3 tcg: use tcg_debug_assert instead of assert (fix performance regression)
The TCG code is quite performance sensitive, but at the same time can
also be quite tricky. That is why asserts that can be enabled with the
--enable-debug-tcg configure option.

This used to work the following way:

| #include "config.h"
|
| ...
|
| #if !defined(CONFIG_DEBUG_TCG) && !defined(NDEBUG)
| /* define it to suppress various consistency checks (faster) */
| #define NDEBUG
| #endif
|
| ...
|
| #include <assert.h>

Since commit 757e725b (tcg: Clean up includes) "config.h" as been
replaced by "qemu/osdep.h" which itself includes <assert.h>. As a
consequence the assertions are always enabled, even when using
--disable-debug-tcg, causing a performance regression, especially on
targets with many registers. For instance on qemu-system-ppc the
speed difference is about 15%.

tcg_debug_assert is controlled directly by CONFIG_DEBUG_TCG and already
uses in some places. This patch replaces all the calls to assert into
calss to tcg_debug_assert.

Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Message-id: 1461228530-14852-1-git-send-email-aurelien@aurel32.net
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2016-04-21 15:41:47 +01:00
Alex Bennée d977e1c2db qemu-log: dfilter-ise exec, out_asm, op and opt_op
This ensures the code generation debug code will honour -dfilter if set.
For the "exec" tracing I've added a new inline macro for efficiency's
sake.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Aurelien Jarno <aurelien@aureL32.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1458052224-9316-8-git-send-email-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:18 +01:00
Alex Bennée 5bd2ec3d7b tcg: pass down TranslationBlock to tcg_code_gen
My later debugging patches need access to the origin PC which is held in
the TranslationBlock structure. Pass down the whole structure as it also
holds the information about the code start point.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson  <rth@twiddle.net>
Message-Id: <1458052224-9316-3-git-send-email-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:17 +01:00
Veronia Bahaa f348b6d1a5 util: move declarations out of qemu-common.h
Move declarations out of qemu-common.h for functions declared in
utils/ files: e.g. include/qemu/path.h for utils/path.c.
Move inline functions out of qemu-common.h and into new files (e.g.
include/qemu/bcd.h)

Signed-off-by: Veronia Bahaa <veroniabahaa@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2016-03-22 22:20:17 +01:00
Peter Maydell ce15110981 tcg: Rename tcg-target.c to tcg-target.inc.c
Rename the per-architecture tcg-target.c files to tcg-target.inc.c.
This makes it clearer that they are not intended to be standalone
C files, but are instead #included into another source file.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <1456238983-10160-2-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-02-23 08:30:38 -08:00
Richard Henderson 91478cefaa tcg: Allocate indirect_base temporaries in a different order
Since we've not got liveness analysis for indirect bases,
placing them at the end of the call-saved registers makes
it more likely that it'll stay live.

Tested-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>
2016-02-23 08:07:14 -08:00