[Version 2][Patch][PR102281]do not add BUILTIN_CLEAR_PADDING for variables that are gimple registers
Qing Zhao
qing.zhao@oracle.com
Wed Oct 20 16:29:42 GMT 2021
> On Oct 18, 2021, at 2:26 PM, Qing Zhao via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
>
> Hi, Jakub,
>
> This is the 2nd version of the patch based on your comment.
>
> Bootstrapped on both x86 and aarch64. Regression testings are ongoing.
The regression testing was done. Looks good.
Okay for committing?
Thanks.
Qing
>
> Please let me know if this is ready for committing?
>
> Thanks a lot.
>
> Qing.
>
> ======================
>
> From d6f60370dee69b5deb3d7ef51873a5e986490782 Mon Sep 17 00:00:00 2001
> From: Qing Zhao <qing.zhao@oracle.com>
> Date: Mon, 18 Oct 2021 19:04:39 +0000
> Subject: [PATCH] PR 102281 (-ftrivial-auto-var-init=zero causes ice)
>
> Do not add call to __builtin_clear_padding when a variable is a gimple
> register or it might not have padding.
>
> gcc/ChangeLog:
>
> 2021-10-18 qing zhao <qing.zhao@oracle.com>
>
> * gimplify.c (gimplify_decl_expr): Do not add call to
> __builtin_clear_padding when a variable is a gimple register
> or it might not have padding.
> (gimplify_init_constructor): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> 2021-10-18 qing zhao <qing.zhao@oracle.com>
>
> * c-c++-common/pr102281.c: New test.
> * gcc.target/i386/auto-init-2.c: Adjust testing case.
> * gcc.target/i386/auto-init-4.c: Likewise.
> * gcc.target/i386/auto-init-6.c: Likewise.
> * gcc.target/aarch64/auto-init-6.c: Likewise.
> ---
> gcc/gimplify.c | 25 ++++++++++++++-----
> gcc/testsuite/c-c++-common/pr102281.c | 17 +++++++++++++
> .../gcc.target/aarch64/auto-init-6.c | 4 +--
> gcc/testsuite/gcc.target/i386/auto-init-2.c | 2 +-
> gcc/testsuite/gcc.target/i386/auto-init-4.c | 10 +++-----
> gcc/testsuite/gcc.target/i386/auto-init-6.c | 7 +++---
> 6 files changed, 47 insertions(+), 18 deletions(-)
> create mode 100644 gcc/testsuite/c-c++-common/pr102281.c
>
> diff --git a/gcc/gimplify.c b/gcc/gimplify.c
> index d8e4b139349..b27dc0ed308 100644
> --- a/gcc/gimplify.c
> +++ b/gcc/gimplify.c
> @@ -1784,8 +1784,8 @@ gimple_add_init_for_auto_var (tree decl,
> that padding is initialized to zero. So, we always initialize paddings
> to zeroes regardless INIT_TYPE.
> To do the padding initialization, we insert a call to
> - __BUILTIN_CLEAR_PADDING (&decl, 0, for_auto_init = true).
> - Note, we add an additional dummy argument for __BUILTIN_CLEAR_PADDING,
> + __builtin_clear_padding (&decl, 0, for_auto_init = true).
> + Note, we add an additional dummy argument for __builtin_clear_padding,
> 'for_auto_init' to distinguish whether this call is for automatic
> variable initialization or not.
> */
> @@ -1954,8 +1954,14 @@ gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p)
> pattern initialization.
> In order to make the paddings as zeroes for pattern init, We
> should add a call to __builtin_clear_padding to clear the
> - paddings to zero in compatiple with CLANG. */
> - if (flag_auto_var_init == AUTO_INIT_PATTERN)
> + paddings to zero in compatiple with CLANG.
> + We cannot insert this call if the variable is a gimple register
> + since __builtin_clear_padding will take the address of the
> + variable. As a result, if a long double/_Complex long double
> + variable will spilled into stack later, its padding is 0XFE. */
> + if (flag_auto_var_init == AUTO_INIT_PATTERN
> + && !is_gimple_reg (decl)
> + && clear_padding_type_may_have_padding_p (TREE_TYPE (decl)))
> gimple_add_padding_init_for_auto_var (decl, is_vla, seq_p);
> }
> }
> @@ -5384,12 +5390,19 @@ gimplify_init_constructor (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p,
>
> /* If the user requests to initialize automatic variables, we
> should initialize paddings inside the variable. Add a call to
> - __BUILTIN_CLEAR_PADDING (&object, 0, for_auto_init = true) to
> + __builtin_clear_pading (&object, 0, for_auto_init = true) to
> initialize paddings of object always to zero regardless of
> INIT_TYPE. Note, we will not insert this call if the aggregate
> variable has be completely cleared already or it's initialized
> - with an empty constructor. */
> + with an empty constructor. We cannot insert this call if the
> + variable is a gimple register since __builtin_clear_padding will take
> + the address of the variable. As a result, if a long double/_Complex long
> + double variable will be spilled into stack later, its padding cannot
> + be cleared with __builtin_clear_padding. We should clear its padding
> + when it is spilled into memory. */
> if (is_init_expr
> + && !is_gimple_reg (object)
> + && clear_padding_type_may_have_padding_p (type)
> && ((AGGREGATE_TYPE_P (type) && !cleared && !is_empty_ctor)
> || !AGGREGATE_TYPE_P (type))
> && is_var_need_auto_init (object))
> diff --git a/gcc/testsuite/c-c++-common/pr102281.c b/gcc/testsuite/c-c++-common/pr102281.c
> new file mode 100644
> index 00000000000..a961451b5a7
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/pr102281.c
> @@ -0,0 +1,17 @@
> +/* PR102281 */
> +/* { dg-do compile } */
> +/* { dg-options "-ftrivial-auto-var-init=zero -Wno-psabi" } */
> +long long var1;
> +float var2;
> +typedef long long V __attribute__((__vector_size__(2 * sizeof(long long))));
> +typedef float W __attribute__((__vector_size__(4 * sizeof(float))));
> +
> +V foo (void)
> +{
> + return (V) {var1};
> +}
> +
> +W bar (void)
> +{
> + return (W) {var2};
> +}
> diff --git a/gcc/testsuite/gcc.target/aarch64/auto-init-6.c b/gcc/testsuite/gcc.target/aarch64/auto-init-6.c
> index 27c16b33678..0456c66f496 100644
> --- a/gcc/testsuite/gcc.target/aarch64/auto-init-6.c
> +++ b/gcc/testsuite/gcc.target/aarch64/auto-init-6.c
> @@ -1,6 +1,6 @@
> /* Verify pattern initialization for complex type automatic variables. */
> /* { dg-do compile } */
> -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand" } */
> +/* { dg-options "-ftrivial-auto-var-init=pattern" } */
>
>
> _Complex long double result;
> @@ -15,4 +15,4 @@ _Complex long double foo()
> return result;
> }
>
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 3 "expand" } } */
> +/* { dg-final { scan-assembler-times "word\t-16843010" 14 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/auto-init-2.c b/gcc/testsuite/gcc.target/i386/auto-init-2.c
> index e22930ae89b..0c59c62dacf 100644
> --- a/gcc/testsuite/gcc.target/i386/auto-init-2.c
> +++ b/gcc/testsuite/gcc.target/i386/auto-init-2.c
> @@ -29,7 +29,7 @@ void foo()
> return;
> }
>
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe" 2 "expand" } } */
> +/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe" 1 "expand" } } */
> /* { dg-final { scan-rtl-dump-times "0xfffffffffffffefe" 1 "expand" } } */
> /* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 2 "expand" { target lp64 } } } */
> /* { dg-final { scan-rtl-dump-times "0xfefefefefefefefe" 3 "expand" { target lp64 } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/auto-init-4.c b/gcc/testsuite/gcc.target/i386/auto-init-4.c
> index 7b46c74a073..1803dd45842 100644
> --- a/gcc/testsuite/gcc.target/i386/auto-init-4.c
> +++ b/gcc/testsuite/gcc.target/i386/auto-init-4.c
> @@ -1,6 +1,6 @@
> /* Verify pattern initialization for floating point type automatic variables. */
> /* { dg-do compile } */
> -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand -march=x86-64 -mtune=generic -msse" } */
> +/* { dg-options "-ftrivial-auto-var-init=pattern -march=x86-64 -mtune=generic -msse" } */
>
> long double result;
>
> @@ -14,8 +14,6 @@ long double foo()
> return result;
> }
>
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 1 "expand" { target { ! ia32 } } } } */
> -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 1 "expand" { target { ! ia32 } } } } */
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 1 "expand" { target { ! ia32 } } } } */
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffefefefe" 2 "expand" { target ia32 } } } */
> -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 2 "expand" { target ia32 } } } */
> +
> +/* { dg-final { scan-assembler-times "long\t-16843010" 5 { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler-times "long\t-16843010" 3 { target { ia32 } } } } */
> diff --git a/gcc/testsuite/gcc.target/i386/auto-init-6.c b/gcc/testsuite/gcc.target/i386/auto-init-6.c
> index f75081edce4..339f8bc2966 100644
> --- a/gcc/testsuite/gcc.target/i386/auto-init-6.c
> +++ b/gcc/testsuite/gcc.target/i386/auto-init-6.c
> @@ -1,6 +1,6 @@
> /* Verify pattern initialization for complex type automatic variables. */
> /* { dg-do compile } */
> -/* { dg-options "-ftrivial-auto-var-init=pattern -fdump-rtl-expand -march=x86-64 -mtune=generic -msse" } */
> +/* { dg-options "-ftrivial-auto-var-init=pattern -march=x86-64 -mtune=generic -msse" } */
>
>
> _Complex long double result;
> @@ -15,5 +15,6 @@ _Complex long double foo()
> return result;
> }
>
> -/* { dg-final { scan-rtl-dump-times "\\\[0xfefefefefefefefe\\\]" 1 "expand" } } */
> -/* { dg-final { scan-rtl-dump-times "0xfffffffffffffffe\\\]\\\) repeated x16" 2 "expand" } } */
> +/* { dg-final { scan-assembler-times "long\t-16843010" 10 { target { ! ia32 } } } } */
> +/* { dg-final { scan-assembler-times "long\t-16843010" 6 { target { ia32 } } } } */
> +
> --
> 2.27.0
>
>
More information about the Gcc-patches
mailing list