On 14/12/2018 23:28, Thomas Preudhomme wrote:
> Hi,
>
> Commit r242693 forced fp to be saved/restored when needed due to an
> instance of GCC using fp as a scratch register to save sp while it's
> being clobbered by an inline asm. The normal path in
> thumb1_compute_save_reg_mask saving callee-saved registers which are
> live in the function does not work in that case because fp is chosen to
> hold sp after that function is called.
>
> Since clobbering sp is now errored out by the compiler and this was the
> only case reported where fp was live but not marked as such when
> thumb1_compute_save_reg_mask is called, I believe the whole commit
> r242693 should be reverted.
>
> ChangeLog entries are as follows:
>
> *** gcc/ChangeLog ***
>
> 2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> Revert:
> 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> PR target/77904
> * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
> in save register mask if it is needed.
>
> *** gcc/testsuite/ChangeLog ***
>
> 2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> Revert:
> 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> PR target/77904
> * gcc.target/arm/pr77904.c: New test.
>
> Testing: Built an arm-none-eabi GCC cross-compiler targeting Armv6S-M
> and regression testsuite does not show any regression.
>
> Ok for stage3?
OK.
R.
>
> Best regards,
>
> Thomas
>
>
> fix_pr77904_test_failure.patch
>
> From 63c52e7bf932947be7122cdc63f6cdc913479259 Mon Sep 17 00:00:00 2001
> From: Thomas Preud'homme <thomas.preudho...@linaro.org>
> Date: Fri, 14 Dec 2018 16:02:59 +0000
> Subject: [PATCH] [PATCH, ARM] Fix PR77904 testcase failure
>
> Hi,
>
> Commit r242693 forced fp to be saved/restored when needed due to an
> instance of GCC using fp as a scratch register to save sp while it's
> being clobbered by an inline asm. The normal path in
> thumb1_compute_save_reg_mask saving callee-saved registers which are
> live in the function does not work in that case because fp is chosen to
> hold sp after that function is called.
>
> Since clobbering sp is now errored out by the compiler and this was the
> only case reported where fp was live but not marked as such when
> thumb1_compute_save_reg_mask is called, I believe the whole commit
> r242693 should be reverted.
>
> ChangeLog entries are as follows:
>
> *** gcc/ChangeLog ***
>
> 2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> Revert:
> 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> PR target/77904
> * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
> in save register mask if it is needed.
>
> *** gcc/testsuite/ChangeLog ***
>
> 2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> Revert:
> 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
>
> PR target/77904
> * gcc.target/arm/pr77904.c: New test.
>
> Testing: Built an arm-none-eabi GCC cross-compiler targeting Armv6S-M
> and regression testsuite does not show any regression.
>
> Ok for stage3?
>
> Best regards,
>
> Thomas
> ---
> gcc/ChangeLog | 9 ++++++
> gcc/config/arm/arm.c | 4 ---
> gcc/testsuite/ChangeLog | 8 +++++
> gcc/testsuite/gcc.target/arm/pr77904.c | 45 --------------------------
> 4 files changed, 17 insertions(+), 49 deletions(-)
> delete mode 100644 gcc/testsuite/gcc.target/arm/pr77904.c
>
> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
> index d8e374fb15f..9caeb1d5e18 100644
> --- a/gcc/ChangeLog
> +++ b/gcc/ChangeLog
> @@ -1,3 +1,12 @@
> +2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + Revert:
> + 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + PR target/77904
> + * config/arm/arm.c (thumb1_compute_save_reg_mask): Mark frame pointer
> + in save register mask if it is needed.
> +
> 2018-11-27 Alan Modra <amo...@gmail.com>
>
> * config/rs6000/aix71.h (ASM_SPEC): Don't select default -maix64
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 40f0574e32e..2ab5d8abc33 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -19553,10 +19553,6 @@ thumb1_compute_save_core_reg_mask (void)
> if (df_regs_ever_live_p (reg) && callee_saved_reg_p (reg))
> mask |= 1 << reg;
>
> - /* Handle the frame pointer as a special case. */
> - if (frame_pointer_needed)
> - mask |= 1 << HARD_FRAME_POINTER_REGNUM;
> -
> if (flag_pic
> && !TARGET_SINGLE_PIC_BASE
> && arm_pic_register != INVALID_REGNUM
> diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
> index 9e1f6d05a45..4e58c8940da 100644
> --- a/gcc/testsuite/ChangeLog
> +++ b/gcc/testsuite/ChangeLog
> @@ -1,3 +1,11 @@
> +2018-12-14 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + Revert:
> + 2016-11-22 Thomas Preud'homme <thomas.preudho...@arm.com>
> +
> + PR target/77904
> + * gcc.target/arm/pr77904.c: New test.
> +
> 2018-11-27 Jozef Lawrynowicz <joze...@mittosystems.com>
>
> * lib/target-supports.exp
> diff --git a/gcc/testsuite/gcc.target/arm/pr77904.c
> b/gcc/testsuite/gcc.target/arm/pr77904.c
> deleted file mode 100644
> index 76728c07e73..00000000000
> --- a/gcc/testsuite/gcc.target/arm/pr77904.c
> +++ /dev/null
> @@ -1,45 +0,0 @@
> -/* { dg-do run } */
> -/* { dg-options "-O2" } */
> -
> -__attribute__ ((noinline, noclone)) void
> -clobber_sp (void)
> -{
> - __asm volatile ("" : : : "sp");
> -}
> -
> -int
> -main (void)
> -{
> - int ret;
> -
> - __asm volatile ("mov\tr4, #0xf4\n\t"
> - "mov\tr5, #0xf5\n\t"
> - "mov\tr6, #0xf6\n\t"
> - "mov\tr7, #0xf7\n\t"
> - "mov\tr0, #0xf8\n\t"
> - "mov\tr8, r0\n\t"
> - "mov\tr0, #0xfa\n\t"
> - "mov\tr10, r0"
> - : : : "r0", "r4", "r5", "r6", "r7", "r8", "r10");
> - clobber_sp ();
> -
> - __asm volatile ("cmp\tr4, #0xf4\n\t"
> - "bne\tfail\n\t"
> - "cmp\tr5, #0xf5\n\t"
> - "bne\tfail\n\t"
> - "cmp\tr6, #0xf6\n\t"
> - "bne\tfail\n\t"
> - "cmp\tr7, #0xf7\n\t"
> - "bne\tfail\n\t"
> - "mov\tr0, r8\n\t"
> - "cmp\tr0, #0xf8\n\t"
> - "bne\tfail\n\t"
> - "mov\tr0, r10\n\t"
> - "cmp\tr0, #0xfa\n\t"
> - "bne\tfail\n\t"
> - "mov\t%0, #1\n"
> - "fail:\n\t"
> - "sub\tr0, #1"
> - : "=r" (ret) : :);
> - return ret;
> -}
>
