Hello,
The attached patch is a standalone part of a slightly more
general change last discussed here:
https://gcc.gnu.org/ml/gcc-patches/2019-11/msg02626.html
Which I re-tested successfully on aarch64-linux (bootstrap
and regression test with --enable-languages=all + local tests
with Ada stack-checking on a gcc-9 based toolchain in-house).
The change moves the definitions of PROBE_STACK_FIRST_REG
and PROBE_STACK_SECOND_REG to a more appropriate place for such
items (here, in aarch64.md as suggested by Richard), and adjust
their value from r9/r10 to r10/r11 to free r9 for a possibly
more general purpose (e.g. as a static chain at least on targets
which have a private use of r18, such as Windows or Vxworks).
Is this ok to commit ?
Thanks in advance!
With Kind Regards,
Olivier
--
> 2019-11-07 Olivier Hainque <[email protected]>
>
> * config/aarch64/aarch64.md: Define PROBE_STACK_FIRST_REGNUM
> and PROBE_STACK_SECOND_REGNUM constants, designating r10/r11.
> Replacements for the PROBE_STACK_FIRST/SECOND_REG constants in
> aarch64.c.
> * config/aarch64/aarch64.c (PROBE_STACK_FIRST_REG): Remove.
> (PROBE_STACK_SECOND_REG): Remove.
> (aarch64_emit_probe_stack_range): Adjust to the _REG -> _REGNUM
> suffix update for PROBE_STACK register numbers.
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 1dfff33..b5a2815 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -5435,10 +5435,6 @@ aarch64_libgcc_cmp_return_mode (void)
#error Cannot use simple address calculation for stack probing
#endif
-/* The pair of scratch registers used for stack probing. */
-#define PROBE_STACK_FIRST_REG R9_REGNUM
-#define PROBE_STACK_SECOND_REG R10_REGNUM
-
/* Emit code to probe a range of stack addresses from FIRST to FIRST+POLY_SIZE,
inclusive. These are offsets from the current stack pointer. */
@@ -5452,7 +5448,7 @@ aarch64_emit_probe_stack_range (HOST_WIDE_INT first,
poly_int64 poly_size)
return;
}
- rtx reg1 = gen_rtx_REG (Pmode, PROBE_STACK_FIRST_REG);
+ rtx reg1 = gen_rtx_REG (Pmode, PROBE_STACK_FIRST_REGNUM);
/* See the same assertion on PROBE_INTERVAL above. */
gcc_assert ((first % ARITH_FACTOR) == 0);
@@ -5510,7 +5506,7 @@ aarch64_emit_probe_stack_range (HOST_WIDE_INT first,
poly_int64 poly_size)
equality test for the loop condition. */
else
{
- rtx reg2 = gen_rtx_REG (Pmode, PROBE_STACK_SECOND_REG);
+ rtx reg2 = gen_rtx_REG (Pmode, PROBE_STACK_SECOND_REGNUM);
/* Step 1: round SIZE to the previous multiple of the interval. */
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index f19e227..2775d75e 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -111,6 +111,10 @@
;; "FFR token": a fake register used for representing the scheduling
;; restrictions on FFR-related operations.
(FFRT_REGNUM 85)
+ ;; The pair of scratch registers used for stack probing with -fstack-check.
+ ;; Leave R9 alone as a possible choice for more general purposes.
+ (PROBE_STACK_FIRST_REGNUM 10)
+ (PROBE_STACK_SECOND_REGNUM 11)
;; Scratch register used by stack clash protection to calculate
;; SVE CFA offsets during probing.
(STACK_CLASH_SVE_CFA_REGNUM 11)
--
1.9.1
