diff mbox series

[scarthgap] Backport: Fix c++: tweak for Wrange-loop-construct

Message ID 20241211171420.3859335-1-sunilkumar.dora@windriver.com
State Superseded
Delegated to: Steve Sakoman
Headers show
Series [scarthgap] Backport: Fix c++: tweak for Wrange-loop-construct | expand

Commit Message

sunilkumar.dora@windriver.com Dec. 11, 2024, 5:14 p.m. UTC 
From: Sunil Dora <sunilkumar.dora@windriver.com>

This commit updates the warning to use a check for "trivially constructible" instead of
"trivially copyable." The original check was incorrect, as "trivially copyable" only applies
to types that can be copied trivially, whereas "trivially constructible" is the correct check
for types that can be trivially default-constructed.

This change ensures the warning is more accurate and aligns with the proper type traits.

LLVM accepted a similar fix:
https://github.com/llvm/llvm-project/issues/47355

PR c++/116731 [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116731]

Upstream-Status: Backport [https://gcc.gnu.org/g:179dc0f0fe01012675c1b430591b9891ce96c26e]

Signed-off-by: Marek Polacek <polacek@redhat.com>
Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
---
 meta/recipes-devtools/gcc/gcc-13.3.inc        |   1 +
 ...ix-c-tweak-for-Wrange-loop-construct.patch | 113 ++++++++++++++++++
 2 files changed, 114 insertions(+)
 create mode 100644 meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch

Comments

Martin Jansa Dec. 11, 2024, 5:20 p.m. UTC | #1 
the commit summary should start with gcc: not backport:.

And the Upstream-Status belongs to .patch it's not necessary do
duplicate that in oe-core commit message.

On Wed, Dec 11, 2024 at 6:14 PM SunilKumar.Dora via
lists.openembedded.org
<SunilKumar.Dora=windriver.com@lists.openembedded.org> wrote:
>
> From: Sunil Dora <sunilkumar.dora@windriver.com>
>
> This commit updates the warning to use a check for "trivially constructible" instead of
> "trivially copyable." The original check was incorrect, as "trivially copyable" only applies
> to types that can be copied trivially, whereas "trivially constructible" is the correct check
> for types that can be trivially default-constructed.
>
> This change ensures the warning is more accurate and aligns with the proper type traits.
>
> LLVM accepted a similar fix:
> https://github.com/llvm/llvm-project/issues/47355
>
> PR c++/116731 [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116731]
>
> Upstream-Status: Backport [https://gcc.gnu.org/g:179dc0f0fe01012675c1b430591b9891ce96c26e]
>
> Signed-off-by: Marek Polacek <polacek@redhat.com>
> Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
> ---
>  meta/recipes-devtools/gcc/gcc-13.3.inc        |   1 +
>  ...ix-c-tweak-for-Wrange-loop-construct.patch | 113 ++++++++++++++++++
>  2 files changed, 114 insertions(+)
>  create mode 100644 meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch
>
> diff --git a/meta/recipes-devtools/gcc/gcc-13.3.inc b/meta/recipes-devtools/gcc/gcc-13.3.inc
> index ffe90c7188..65477a29bc 100644
> --- a/meta/recipes-devtools/gcc/gcc-13.3.inc
> +++ b/meta/recipes-devtools/gcc/gcc-13.3.inc
> @@ -66,6 +66,7 @@ SRC_URI = "${BASEURI} \
>             file://0024-Avoid-hardcoded-build-paths-into-ppc-libgcc.patch \
>             file://0025-gcc-testsuite-tweaks-for-mips-OE.patch \
>             file://0027-Fix-gcc-vect-module-testcases.patch \
> +          file://0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch \
>             file://gcc.git-ab884fffe3fc82a710bea66ad651720d71c938b8.patch \
>  "
>  SRC_URI[sha256sum] = "0845e9621c9543a13f484e94584a49ffc0129970e9914624235fc1d061a0c083"
> diff --git a/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch b/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch
> new file mode 100644
> index 0000000000..406578eebf
> --- /dev/null
> +++ b/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch
> @@ -0,0 +1,113 @@
> +From 096ff216265bb114b28a5b717d0139f37d03c322 Mon Sep 17 00:00:00 2001
> +From: Sunil Dora <sunilkumar.dora@windriver.com>
> +Date: Wed, 11 Dec 2024 00:53:31 -0800
> +Subject: [PATCH] Backport: Fix c++: tweak for Wrange-loop-construct
> +
> +This commit updates the warning to use a check for "trivially constructible" instead of
> +"trivially copyable." The original check was incorrect, as "trivially copyable" only applies
> +to types that can be copied trivially, whereas "trivially constructible" is the correct check
> +for types that can be trivially default-constructed.
> +
> +This change ensures the warning is more accurate and aligns with the proper type traits.
> +
> +LLVM accepted a similar fix:
> +https://github.com/llvm/llvm-project/issues/47355
> +
> +PR c++/116731 [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116731]
> +
> +Upstream-Status: Backport [https://gcc.gnu.org/g:179dc0f0fe01012675c1b430591b9891ce96c26e]
> +
> +Signed-off-by: Marek Polacek <polacek@redhat.com>
> +Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
> +---
> + gcc/cp/parser.cc                              |  7 ++-
> + .../g++.dg/warn/Wrange-loop-construct3.C      | 57 +++++++++++++++++++
> + 2 files changed, 61 insertions(+), 3 deletions(-)
> + create mode 100644 gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
> +
> +diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> +index 4e67da6ff..5dd94357d 100644
> +--- a/gcc/cp/parser.cc
> ++++ b/gcc/cp/parser.cc
> +@@ -13854,11 +13854,12 @@ warn_for_range_copy (tree decl, tree expr)
> +   else if (!CP_TYPE_CONST_P (type))
> +     return;
> +
> +-  /* Since small trivially copyable types are cheap to copy, we suppress the
> +-     warning for them.  64B is a common size of a cache line.  */
> ++  /* Since small trivially constructible types are cheap to construct, we
> ++     suppress the warning for them.  64B is a common size of a cache line.  */
> ++  tree list = build_tree_list (NULL_TREE, TREE_TYPE (expr));
> +   if (TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
> +       || (tree_to_uhwi (TYPE_SIZE_UNIT (type)) <= 64
> +-        && trivially_copyable_p (type)))
> ++        && is_trivially_xible (INIT_EXPR, type, list)))
> +     return;
> +
> +   /* If we can initialize a reference directly, suggest that to avoid the
> +diff --git a/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C b/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
> +new file mode 100644
> +index 000000000..3d9d0c908
> +--- /dev/null
> ++++ b/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
> +@@ -0,0 +1,57 @@
> ++// PR c++/116731
> ++// { dg-do compile { target c++11 } }
> ++// { dg-options "-Wrange-loop-construct" }
> ++
> ++void
> ++f0 ()
> ++{
> ++  struct S {
> ++    char a[64];
> ++    S& operator=(const S&) { return *this; };
> ++  };
> ++
> ++  S arr[8];
> ++  for (const auto r : arr)
> ++    (void) r;
> ++}
> ++
> ++void
> ++f1 ()
> ++{
> ++  struct S {
> ++    char a[65];
> ++    S& operator=(const S&) { return *this; };
> ++  };
> ++
> ++  S arr[8];
> ++  for (const auto r : arr) // { dg-warning "creates a copy" }
> ++    (void) r;
> ++}
> ++
> ++void
> ++f2 ()
> ++{
> ++  struct S {
> ++    char a[64];
> ++    S& operator=(const S&) { return *this; };
> ++    ~S() { }
> ++  };
> ++
> ++  S arr[8];
> ++  for (const auto r : arr) // { dg-warning "creates a copy" }
> ++    (void) r;
> ++}
> ++
> ++void
> ++f3 ()
> ++{
> ++  struct S {
> ++    char a[65];
> ++    S& operator=(const S&) { return *this; };
> ++    ~S() { }
> ++  };
> ++
> ++  S arr[8];
> ++  for (const auto r : arr) // { dg-warning "creates a copy" }
> ++    (void) r;
> ++}
> +--
> +2.43.0
> +
> --
> 2.43.0
>
>
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>
diff mbox series

Patch

diff --git a/meta/recipes-devtools/gcc/gcc-13.3.inc b/meta/recipes-devtools/gcc/gcc-13.3.inc
index ffe90c7188..65477a29bc 100644
--- a/meta/recipes-devtools/gcc/gcc-13.3.inc
+++ b/meta/recipes-devtools/gcc/gcc-13.3.inc
@@ -66,6 +66,7 @@  SRC_URI = "${BASEURI} \
            file://0024-Avoid-hardcoded-build-paths-into-ppc-libgcc.patch \
            file://0025-gcc-testsuite-tweaks-for-mips-OE.patch \
            file://0027-Fix-gcc-vect-module-testcases.patch \
+	   file://0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch \
            file://gcc.git-ab884fffe3fc82a710bea66ad651720d71c938b8.patch \
 "
 SRC_URI[sha256sum] = "0845e9621c9543a13f484e94584a49ffc0129970e9914624235fc1d061a0c083"
diff --git a/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch b/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch
new file mode 100644
index 0000000000..406578eebf
--- /dev/null
+++ b/meta/recipes-devtools/gcc/gcc/0028-Backport-Fix-c-tweak-for-Wrange-loop-construct.patch
@@ -0,0 +1,113 @@ 
+From 096ff216265bb114b28a5b717d0139f37d03c322 Mon Sep 17 00:00:00 2001
+From: Sunil Dora <sunilkumar.dora@windriver.com>
+Date: Wed, 11 Dec 2024 00:53:31 -0800
+Subject: [PATCH] Backport: Fix c++: tweak for Wrange-loop-construct
+
+This commit updates the warning to use a check for "trivially constructible" instead of
+"trivially copyable." The original check was incorrect, as "trivially copyable" only applies
+to types that can be copied trivially, whereas "trivially constructible" is the correct check
+for types that can be trivially default-constructed.
+
+This change ensures the warning is more accurate and aligns with the proper type traits.
+
+LLVM accepted a similar fix:
+https://github.com/llvm/llvm-project/issues/47355
+
+PR c++/116731 [https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116731]
+
+Upstream-Status: Backport [https://gcc.gnu.org/g:179dc0f0fe01012675c1b430591b9891ce96c26e]
+
+Signed-off-by: Marek Polacek <polacek@redhat.com>
+Signed-off-by: Sunil Dora <sunilkumar.dora@windriver.com>
+---
+ gcc/cp/parser.cc                              |  7 ++-
+ .../g++.dg/warn/Wrange-loop-construct3.C      | 57 +++++++++++++++++++
+ 2 files changed, 61 insertions(+), 3 deletions(-)
+ create mode 100644 gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
+
+diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
+index 4e67da6ff..5dd94357d 100644
+--- a/gcc/cp/parser.cc
++++ b/gcc/cp/parser.cc
+@@ -13854,11 +13854,12 @@ warn_for_range_copy (tree decl, tree expr)
+   else if (!CP_TYPE_CONST_P (type))
+     return;
+ 
+-  /* Since small trivially copyable types are cheap to copy, we suppress the
+-     warning for them.  64B is a common size of a cache line.  */
++  /* Since small trivially constructible types are cheap to construct, we
++     suppress the warning for them.  64B is a common size of a cache line.  */
++  tree list = build_tree_list (NULL_TREE, TREE_TYPE (expr));
+   if (TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST
+       || (tree_to_uhwi (TYPE_SIZE_UNIT (type)) <= 64
+-	  && trivially_copyable_p (type)))
++	  && is_trivially_xible (INIT_EXPR, type, list)))
+     return;
+ 
+   /* If we can initialize a reference directly, suggest that to avoid the
+diff --git a/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C b/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
+new file mode 100644
+index 000000000..3d9d0c908
+--- /dev/null
++++ b/gcc/testsuite/g++.dg/warn/Wrange-loop-construct3.C
+@@ -0,0 +1,57 @@
++// PR c++/116731
++// { dg-do compile { target c++11 } }
++// { dg-options "-Wrange-loop-construct" }
++
++void
++f0 ()
++{
++  struct S {
++    char a[64];
++    S& operator=(const S&) { return *this; };
++  };
++
++  S arr[8];
++  for (const auto r : arr)
++    (void) r;
++}
++
++void
++f1 ()
++{
++  struct S {
++    char a[65];
++    S& operator=(const S&) { return *this; };
++  };
++
++  S arr[8];
++  for (const auto r : arr) // { dg-warning "creates a copy" }
++    (void) r;
++}
++
++void
++f2 ()
++{
++  struct S {
++    char a[64];
++    S& operator=(const S&) { return *this; };
++    ~S() { }
++  };
++
++  S arr[8];
++  for (const auto r : arr) // { dg-warning "creates a copy" }
++    (void) r;
++}
++
++void
++f3 ()
++{
++  struct S {
++    char a[65];
++    S& operator=(const S&) { return *this; };
++    ~S() { }
++  };
++
++  S arr[8];
++  for (const auto r : arr) // { dg-warning "creates a copy" }
++    (void) r;
++}
+-- 
+2.43.0
+