This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH][IRA] Analysis of register usage of functions for usage by IRA.
- From: Tom de Vries <Tom_deVries at mentor dot com>
- To: Richard Earnshaw <rearnsha at arm dot com>
- Cc: Vladimir Makarov <vmakarov at redhat dot com>, Richard Sandiford <rdsandiford at googlemail dot com>, Paolo Bonzini <bonzini at gnu dot org>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 13 Jan 2014 17:16:30 +0100
- Subject: Re: [PATCH][IRA] Analysis of register usage of functions for usage by IRA.
- Authentication-results: sourceware.org; auth=none
- References: <510282FE dot 1060809 at mentor dot com> <5102A694 dot 5010000 at redhat dot com> <5113FC6B dot 7090702 at mentor dot com> <511C1538 dot 308 at redhat dot com> <514199BC dot 9070608 at mentor dot com> <5141E8A1 dot 5010203 at redhat dot com> <51558EF4 dot 1030106 at mentor dot com> <51570E59 dot 2020603 at mentor dot com> <52CEB533 dot 50308 at arm dot com> <52CF099B dot 4070006 at mentor dot com> <52CFDBDF dot 7060105 at arm dot com>
On 10-01-14 12:39, Richard Earnshaw wrote:
>>Consequently, you'll need to add a patch for AArch64 which has two
>>registers clobbered by PLT-based calls.
>>
>
>Thanks for pointing that out. That's r16 and r17, right? I can propose the hook
>for AArch64, once we all agree on how the hook should look.
>
Yes; and thanks!
Hi Richard,
I'm posting this patch that implements the TARGET_FN_OTHER_HARD_REG_USAGE hook
for aarch64. It uses the conservative hook format for now.
I've build gcc and cc1 with the patch, and observed the impact on this code snippet:
...
static int
bar (int x)
{
return x + 3;
}
int
foo (int y)
{
return y + bar (y);
}
...
AFAICT, that looks as expected:
...
$ gcc fuse-caller-save.c -mno-lra -fno-use-caller-save -O2 -S -o- > 1
$ gcc fuse-caller-save.c -mno-lra -fuse-caller-save -O2 -S -o- > 2
$ diff -u 1 2
--- 1 2014-01-13 16:51:24.000000000 +0100
+++ 2 2014-01-13 16:51:19.000000000 +0100
@@ -11,14 +11,12 @@
.global foo
.type foo, %function
foo:
- stp x29, x30, [sp, -32]!
+ stp x29, x30, [sp, -16]!
+ mov w1, w0
add x29, sp, 0
- str x19, [sp,16]
- mov w19, w0
bl bar
- add w0, w0, w19
- ldr x19, [sp,16]
- ldp x29, x30, [sp], 32
+ ldp x29, x30, [sp], 16
+ add w0, w0, w1
ret
.size foo, .-foo
.section .text.startup,"ax",%progbits
...
Btw, the results are the same for -mno-lra and -mlra. I'm just using the
-mno-lra version here because the -mlra version of -fuse-caller-save is still in
review ( http://gcc.gnu.org/ml/gcc-patches/2013-12/msg00586.html ).
Thanks,
- Tom
2014-01-11 Tom de Vries <tom@codesourcery.com>
* config/aarch64/aarch64.c (TARGET_FN_OTHER_HARD_REG_USAGE): Redefine as
aarch64_fn_other_hard_reg_usage.
(aarch64_fn_other_hard_reg_usage): New function.
---
gcc/config/aarch64/aarch64.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 3b1f6b5..295fd5d 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -3287,6 +3287,16 @@ aarch64_fixed_condition_code_regs (unsigned int *p1, unsigned int *p2)
return true;
}
+/* Implement TARGET_FN_OTHER_HARD_REG_USAGE. */
+
+static bool
+aarch64_fn_other_hard_reg_usage (struct hard_reg_set_container *regs)
+{
+ SET_HARD_REG_BIT (regs->set, R16_REGNUM);
+ SET_HARD_REG_BIT (regs->set, R17_REGNUM);
+ return true;
+}
+
enum machine_mode
aarch64_select_cc_mode (RTX_CODE code, rtx x, rtx y)
{
@@ -8472,6 +8482,11 @@ aarch64_vectorize_vec_perm_const_ok (enum machine_mode vmode,
#undef TARGET_FIXED_CONDITION_CODE_REGS
#define TARGET_FIXED_CONDITION_CODE_REGS aarch64_fixed_condition_code_regs
+#undef TARGET_FN_OTHER_HARD_REG_USAGE
+#define TARGET_FN_OTHER_HARD_REG_USAGE \
+ aarch64_fn_other_hard_reg_usage
+
+
struct gcc_target targetm = TARGET_INITIALIZER;
#include "gt-aarch64.h"
--
1.8.3.2