[PATCH] build: remove obsolete compiler checks

[PATCH] build: remove obsolete compiler checks

[Bruce Richardson]

DPDK now recommends compiler versions GCC 8+, and Clang 7+, so remove
checks and workarounds for versions old than these.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
---
 config/meson.build                  |  5 ----
 drivers/event/meson.build           |  5 +---
 drivers/meson.build                 |  2 +-
 drivers/net/virtio/meson.build      |  2 +-
 lib/eal/arm/include/rte_memcpy_64.h |  8 -------
 lib/eal/arm/include/rte_vect.h      | 37 ++---------------------------
 lib/eal/ppc/include/rte_altivec.h   |  1 -
 lib/meson.build                     |  2 +-
 lib/vhost/meson.build               |  4 ++--
 lib/vhost/vhost.c                   | 16 -------------
 10 files changed, 8 insertions(+), 74 deletions(-)

diff --git a/config/meson.build b/config/meson.build
index f31fef216c..c7a780dcc8 100644
--- a/config/meson.build
+++ b/config/meson.build
@@ -492,11 +492,6 @@ if get_option('b_lto')
     else
         error('compiler does not support fat LTO objects - please turn LTO off')
     endif
-    # workaround for gcc bug 81440
-    if cc.get_id() == 'gcc' and cc.version().version_compare('<8.0')
-        add_project_arguments('-Wno-lto-type-mismatch', language: 'c')
-        add_project_link_arguments('-Wno-lto-type-mismatch', language: 'c')
-    endif
 endif
 
 if get_option('b_sanitize') == 'address' or get_option('b_sanitize') == 'address,undefined'
diff --git a/drivers/event/meson.build b/drivers/event/meson.build
index d6706b57f7..b0bc3f40f1 100644
--- a/drivers/event/meson.build
+++ b/drivers/event/meson.build
@@ -14,9 +14,6 @@ drivers = [
         'opdl',
         'skeleton',
         'sw',
+        'octeontx',
 ]
-if not (toolchain == 'gcc' and cc.version().version_compare('<4.8.6') and
-        dpdk_conf.has('RTE_ARCH_ARM64'))
-    drivers += 'octeontx'
-endif
 std_deps = ['eventdev', 'kvargs']
diff --git a/drivers/meson.build b/drivers/meson.build
index b62880db02..2760f4d593 100644
--- a/drivers/meson.build
+++ b/drivers/meson.build
@@ -237,7 +237,7 @@ foreach subpath:subdirs
         enabled_drivers += name
         lib_name = '_'.join(['rte', class, name])
         cflags += '-DRTE_LOG_DEFAULT_LOGTYPE=' + '.'.join([log_prefix, name])
-        if annotate_locks and cc.get_id() == 'clang' and cc.version().version_compare('>=3.5.0')
+        if annotate_locks and cc.get_id() == 'clang'
             cflags += '-DRTE_ANNOTATE_LOCKS'
             cflags += '-Wthread-safety'
         endif
diff --git a/drivers/net/virtio/meson.build b/drivers/net/virtio/meson.build
index d3caa3a3b4..a9ff87e863 100644
--- a/drivers/net/virtio/meson.build
+++ b/drivers/net/virtio/meson.build
@@ -31,7 +31,7 @@ if arch_subdir == 'x86'
         sources_avx512 += files('virtio_rxtx_packed.c')
         if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
             cflags += '-DVIRTIO_GCC_UNROLL_PRAGMA'
-        elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
+        elif (toolchain == 'clang')
             cflags += '-DVIRTIO_CLANG_UNROLL_PRAGMA'
         endif
     endif
diff --git a/lib/eal/arm/include/rte_memcpy_64.h b/lib/eal/arm/include/rte_memcpy_64.h
index 90039039be..57fe24eb10 100644
--- a/lib/eal/arm/include/rte_memcpy_64.h
+++ b/lib/eal/arm/include/rte_memcpy_64.h
@@ -89,14 +89,6 @@ n <= (size_t)RTE_ARM64_MEMCPY_UNALIGNED_THRESHOLD)
  **************************************/
 
 
-#if RTE_CC_IS_GNU && !defined RTE_ARM64_MEMCPY_SKIP_GCC_VER_CHECK
-#if (GCC_VERSION < 50400)
-#warning "The GCC version is quite old, which may result in sub-optimal \
-performance of the compiled code. It is suggested that at least GCC 5.4.0 \
-be used."
-#endif
-#endif
-
 static __rte_always_inline
 void rte_mov16(uint8_t *dst, const uint8_t *src)
 {
diff --git a/lib/eal/arm/include/rte_vect.h b/lib/eal/arm/include/rte_vect.h
index c97d299a3e..149458288e 100644
--- a/lib/eal/arm/include/rte_vect.h
+++ b/lib/eal/arm/include/rte_vect.h
@@ -67,11 +67,8 @@ vaddvq_u16(uint16x8_t a)
 
 #endif
 
-#if (defined(RTE_ARCH_ARM) && defined(RTE_ARCH_32)) || \
-(defined(RTE_ARCH_ARM64) && RTE_CC_IS_GNU && (GCC_VERSION < 70000))
-/* NEON intrinsic vcopyq_laneq_u32() is not supported in ARMv7-A(AArch32)
- * On AArch64, this intrinsic is supported since GCC version 7.
- */
+#if defined(RTE_ARCH_ARM) && defined(RTE_ARCH_32)
+/* NEON intrinsic vcopyq_laneq_u32() is not supported in ARMv7-A(AArch32) */
 static inline uint32x4_t
 vcopyq_laneq_u32(uint32x4_t a, const int lane_a,
 		 uint32x4_t b, const int lane_b)
@@ -80,36 +77,6 @@ vcopyq_laneq_u32(uint32x4_t a, const int lane_a,
 }
 #endif
 
-#if defined(RTE_ARCH_ARM64)
-#if RTE_CC_IS_GNU && (GCC_VERSION < 70000)
-
-/* NEON intrinsic vreinterpretq_u64_p128() is supported since GCC version 7 */
-static inline uint64x2_t
-vreinterpretq_u64_p128(poly128_t x)
-{
-	return (uint64x2_t)x;
-}
-
-/* NEON intrinsic vreinterpretq_p64_u64() is supported since GCC version 7 */
-static inline poly64x2_t
-vreinterpretq_p64_u64(uint64x2_t x)
-{
-	return (poly64x2_t)x;
-}
-
-/* NEON intrinsic vgetq_lane_p64() is supported since GCC version 7 */
-static inline poly64_t
-vgetq_lane_p64(poly64x2_t x, const int lane)
-{
-	RTE_ASSERT(lane >= 0 && lane <= 1);
-
-	poly64_t *p = (poly64_t *)&x;
-
-	return p[lane];
-}
-#endif
-#endif
-
 /*
  * If (0 <= index <= 15), then call the ASIMD ext instruction on the
  * 128 bit regs v0 and v1 with the appropriate index.
diff --git a/lib/eal/ppc/include/rte_altivec.h b/lib/eal/ppc/include/rte_altivec.h
index 7c088d2d16..bc8548f11e 100644
--- a/lib/eal/ppc/include/rte_altivec.h
+++ b/lib/eal/ppc/include/rte_altivec.h
@@ -6,7 +6,6 @@
 #ifndef _RTE_ALTIVEC_H_
 #define _RTE_ALTIVEC_H_
 
-/* To include altivec.h, GCC version must be >= 4.8 */
 #include <altivec.h>
 
 /*
diff --git a/lib/meson.build b/lib/meson.build
index 0d56b2083b..a67efaf718 100644
--- a/lib/meson.build
+++ b/lib/meson.build
@@ -244,7 +244,7 @@ foreach l:libraries
         cflags += '-DRTE_USE_FUNCTION_VERSIONING'
     endif
     cflags += '-DRTE_LOG_DEFAULT_LOGTYPE=lib.' + l
-    if annotate_locks and cc.get_id() == 'clang' and cc.version().version_compare('>=3.5.0')
+    if annotate_locks and cc.get_id() == 'clang'
         cflags += '-DRTE_ANNOTATE_LOCKS'
         cflags += '-Wthread-safety'
     endif
diff --git a/lib/vhost/meson.build b/lib/vhost/meson.build
index 9c6325aa0e..a74d0cff7c 100644
--- a/lib/vhost/meson.build
+++ b/lib/vhost/meson.build
@@ -8,9 +8,9 @@ endif
 if has_libnuma
     dpdk_conf.set10('RTE_LIBRTE_VHOST_NUMA', true)
 endif
-if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
+if (toolchain == 'gcc')
     cflags += '-DVHOST_GCC_UNROLL_PRAGMA'
-elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
+elif (toolchain == 'clang')
     cflags += '-DVHOST_CLANG_UNROLL_PRAGMA'
 endif
 dpdk_conf.set('RTE_LIBRTE_VHOST_POSTCOPY', cc.has_header('linux/userfaultfd.h'))
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index a2e3e2635d..416f082dca 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -128,16 +128,8 @@ __vhost_iova_to_vva(struct virtio_net *dev, struct vhost_virtqueue *vq,
 static __rte_always_inline void
 vhost_set_bit(unsigned int nr, volatile uint8_t *addr)
 {
-#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION < 70100)
-	/*
-	 * __sync_ built-ins are deprecated, but rte_atomic_ ones
-	 * are sub-optimized in older GCC versions.
-	 */
-	__sync_fetch_and_or_1(addr, (1U << nr));
-#else
 	rte_atomic_fetch_or_explicit((volatile uint8_t __rte_atomic *)addr, (1U << nr),
 		rte_memory_order_relaxed);
-#endif
 }
 
 static __rte_always_inline void
@@ -207,17 +199,9 @@ __vhost_log_cache_sync(struct virtio_net *dev, struct vhost_virtqueue *vq)
 	for (i = 0; i < vq->log_cache_nb_elem; i++) {
 		struct log_cache_entry *elem = vq->log_cache + i;
 
-#if defined(RTE_TOOLCHAIN_GCC) && (GCC_VERSION < 70100)
-		/*
-		 * '__sync' builtins are deprecated, but 'rte_atomic' ones
-		 * are sub-optimized in older GCC versions.
-		 */
-		__sync_fetch_and_or(log_base + elem->offset, elem->val);
-#else
 		rte_atomic_fetch_or_explicit(
 			(unsigned long __rte_atomic *)(log_base + elem->offset),
 			elem->val, rte_memory_order_relaxed);
-#endif
 	}
 
 	rte_atomic_thread_fence(rte_memory_order_release);
-- 
2.48.1

Re: [PATCH] build: remove obsolete compiler checks

[David Marchand]

On Fri, Jul 18, 2025 at 2:14 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> DPDK now recommends compiler versions GCC 8+, and Clang 7+, so remove
> checks and workarounds for versions old than these.
>
> Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  config/meson.build                  |  5 ----
>  drivers/event/meson.build           |  5 +---
>  drivers/meson.build                 |  2 +-
>  drivers/net/virtio/meson.build      |  2 +-
>  lib/eal/arm/include/rte_memcpy_64.h |  8 -------
>  lib/eal/arm/include/rte_vect.h      | 37 ++---------------------------
>  lib/eal/ppc/include/rte_altivec.h   |  1 -
>  lib/meson.build                     |  2 +-
>  lib/vhost/meson.build               |  4 ++--
>  lib/vhost/vhost.c                   | 16 -------------
>  10 files changed, 8 insertions(+), 74 deletions(-)

Two nits:

[snip]

> diff --git a/drivers/event/meson.build b/drivers/event/meson.build
> index d6706b57f7..b0bc3f40f1 100644
> --- a/drivers/event/meson.build
> +++ b/drivers/event/meson.build
> @@ -14,9 +14,6 @@ drivers = [
>          'opdl',
>          'skeleton',
>          'sw',
> +        'octeontx',
>  ]

Sort alphabetically?


> -if not (toolchain == 'gcc' and cc.version().version_compare('<4.8.6') and
> -        dpdk_conf.has('RTE_ARCH_ARM64'))
> -    drivers += 'octeontx'
> -endif
>  std_deps = ['eventdev', 'kvargs']

[snip]

> diff --git a/lib/eal/arm/include/rte_memcpy_64.h b/lib/eal/arm/include/rte_memcpy_64.h
> index 90039039be..57fe24eb10 100644
> --- a/lib/eal/arm/include/rte_memcpy_64.h
> +++ b/lib/eal/arm/include/rte_memcpy_64.h
> @@ -89,14 +89,6 @@ n <= (size_t)RTE_ARM64_MEMCPY_UNALIGNED_THRESHOLD)
>   **************************************/
>
>
> -#if RTE_CC_IS_GNU && !defined RTE_ARM64_MEMCPY_SKIP_GCC_VER_CHECK
> -#if (GCC_VERSION < 50400)
> -#warning "The GCC version is quite old, which may result in sub-optimal \
> -performance of the compiled code. It is suggested that at least GCC 5.4.0 \
> -be used."
> -#endif
> -#endif
> -

This flag can be removed from meson too.
config/arm/meson.build:        #
['RTE_ARM64_MEMCPY_SKIP_GCC_VER_CHECK', false],


>  static __rte_always_inline
>  void rte_mov16(uint8_t *dst, const uint8_t *src)
>  {


-- 
David Marchand

Re: [PATCH] build: remove obsolete compiler checks

[Bruce Richardson]

On Fri, Jul 18, 2025 at 02:21:45PM +0200, David Marchand wrote:
> On Fri, Jul 18, 2025 at 2:14 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > DPDK now recommends compiler versions GCC 8+, and Clang 7+, so remove
> > checks and workarounds for versions old than these.
> >
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > ---
> >  config/meson.build                  |  5 ----
> >  drivers/event/meson.build           |  5 +---
> >  drivers/meson.build                 |  2 +-
> >  drivers/net/virtio/meson.build      |  2 +-
> >  lib/eal/arm/include/rte_memcpy_64.h |  8 -------
> >  lib/eal/arm/include/rte_vect.h      | 37 ++---------------------------
> >  lib/eal/ppc/include/rte_altivec.h   |  1 -
> >  lib/meson.build                     |  2 +-
> >  lib/vhost/meson.build               |  4 ++--
> >  lib/vhost/vhost.c                   | 16 -------------
> >  10 files changed, 8 insertions(+), 74 deletions(-)
> 
> Two nits:
> 
> [snip]
> 
> > diff --git a/drivers/event/meson.build b/drivers/event/meson.build
> > index d6706b57f7..b0bc3f40f1 100644
> > --- a/drivers/event/meson.build
> > +++ b/drivers/event/meson.build
> > @@ -14,9 +14,6 @@ drivers = [
> >          'opdl',
> >          'skeleton',
> >          'sw',
> > +        'octeontx',
> >  ]
> 
> Sort alphabetically?
> 

Absolutely, yes.

> 
> > -if not (toolchain == 'gcc' and cc.version().version_compare('<4.8.6') and
> > -        dpdk_conf.has('RTE_ARCH_ARM64'))
> > -    drivers += 'octeontx'
> > -endif
> >  std_deps = ['eventdev', 'kvargs']
> 
> [snip]
> 
> > diff --git a/lib/eal/arm/include/rte_memcpy_64.h b/lib/eal/arm/include/rte_memcpy_64.h
> > index 90039039be..57fe24eb10 100644
> > --- a/lib/eal/arm/include/rte_memcpy_64.h
> > +++ b/lib/eal/arm/include/rte_memcpy_64.h
> > @@ -89,14 +89,6 @@ n <= (size_t)RTE_ARM64_MEMCPY_UNALIGNED_THRESHOLD)
> >   **************************************/
> >
> >
> > -#if RTE_CC_IS_GNU && !defined RTE_ARM64_MEMCPY_SKIP_GCC_VER_CHECK
> > -#if (GCC_VERSION < 50400)
> > -#warning "The GCC version is quite old, which may result in sub-optimal \
> > -performance of the compiled code. It is suggested that at least GCC 5.4.0 \
> > -be used."
> > -#endif
> > -#endif
> > -
> 
> This flag can be removed from meson too.
> config/arm/meson.build:        #
> ['RTE_ARM64_MEMCPY_SKIP_GCC_VER_CHECK', false],
> 
Yep, seems there are no more references to it in the code.

Will fix in V2, after all CI's have had their chance to have their say.

/Bruce

Re: [PATCH] build: remove obsolete compiler checks

[David Marchand]

On Fri, Jul 18, 2025 at 2:14 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
> diff --git a/drivers/net/virtio/meson.build b/drivers/net/virtio/meson.build
> index d3caa3a3b4..a9ff87e863 100644
> --- a/drivers/net/virtio/meson.build
> +++ b/drivers/net/virtio/meson.build
> @@ -31,7 +31,7 @@ if arch_subdir == 'x86'
>          sources_avx512 += files('virtio_rxtx_packed.c')
>          if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
>              cflags += '-DVIRTIO_GCC_UNROLL_PRAGMA'
> -        elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
> +        elif (toolchain == 'clang')
>              cflags += '-DVIRTIO_CLANG_UNROLL_PRAGMA'
>          endif
>      endif

One other nit, not blocking.

There should be no need for special casing clang vs gcc, since clang
supports gcc syntax in general.
https://clang.llvm.org/docs/AttributeReference.html#pragma-unroll-pragma-nounroll

The code could check for RTE_TOOLCHAIN_GCC/CLANG directly, and we
don't need a separate define passed from cmdline.

(idem in lib/vhost)


-- 
David Marchand

Re: [PATCH] build: remove obsolete compiler checks

[Bruce Richardson]

On Fri, Jul 18, 2025 at 02:45:48PM +0200, David Marchand wrote:
> On Fri, Jul 18, 2025 at 2:14 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> > diff --git a/drivers/net/virtio/meson.build b/drivers/net/virtio/meson.build
> > index d3caa3a3b4..a9ff87e863 100644
> > --- a/drivers/net/virtio/meson.build
> > +++ b/drivers/net/virtio/meson.build
> > @@ -31,7 +31,7 @@ if arch_subdir == 'x86'
> >          sources_avx512 += files('virtio_rxtx_packed.c')
> >          if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
> >              cflags += '-DVIRTIO_GCC_UNROLL_PRAGMA'
> > -        elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
> > +        elif (toolchain == 'clang')
> >              cflags += '-DVIRTIO_CLANG_UNROLL_PRAGMA'
> >          endif
> >      endif
> 
> One other nit, not blocking.
> 
> There should be no need for special casing clang vs gcc, since clang
> supports gcc syntax in general.
> https://clang.llvm.org/docs/AttributeReference.html#pragma-unroll-pragma-nounroll
> 
I was actually thinking of doing a follow-up patch to remove the "if" and
instead do:

	cflags += '-DVIRTIO_' + toolchain.to_upper() + "_UNROLL_PRAGMA"

on the basis that having a define for any other unknown compilers would be
harmless. However, you are right that there seems to be little reason to do
this in meson.build, and the code can do it directly itself. I'll leave
this part as it is in the patch for now.

/Bruce

Re: [PATCH] build: remove obsolete compiler checks

[David Marchand]

On Fri, Jul 18, 2025 at 3:06 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> On Fri, Jul 18, 2025 at 02:45:48PM +0200, David Marchand wrote:
> > On Fri, Jul 18, 2025 at 2:14 PM Bruce Richardson
> > <bruce.richardson@intel.com> wrote:
> > > diff --git a/drivers/net/virtio/meson.build b/drivers/net/virtio/meson.build
> > > index d3caa3a3b4..a9ff87e863 100644
> > > --- a/drivers/net/virtio/meson.build
> > > +++ b/drivers/net/virtio/meson.build
> > > @@ -31,7 +31,7 @@ if arch_subdir == 'x86'
> > >          sources_avx512 += files('virtio_rxtx_packed.c')
> > >          if (toolchain == 'gcc' and cc.version().version_compare('>=8.3.0'))
> > >              cflags += '-DVIRTIO_GCC_UNROLL_PRAGMA'
> > > -        elif (toolchain == 'clang' and cc.version().version_compare('>=3.7.0'))
> > > +        elif (toolchain == 'clang')
> > >              cflags += '-DVIRTIO_CLANG_UNROLL_PRAGMA'
> > >          endif
> > >      endif
> >
> > One other nit, not blocking.
> >
> > There should be no need for special casing clang vs gcc, since clang
> > supports gcc syntax in general.
> > https://clang.llvm.org/docs/AttributeReference.html#pragma-unroll-pragma-nounroll
> >
> I was actually thinking of doing a follow-up patch to remove the "if" and
> instead do:
>
>         cflags += '-DVIRTIO_' + toolchain.to_upper() + "_UNROLL_PRAGMA"
>
> on the basis that having a define for any other unknown compilers would be
> harmless. However, you are right that there seems to be little reason to do
> this in meson.build, and the code can do it directly itself. I'll leave
> this part as it is in the patch for now.

Cc: Maxime (who is off atm)

I wonder if this pragma stuff really helps..
One quick test on the loop in vhost_flush_enqueue_batch_packed() shows
the same generated code with gcc 10 and gcc 15 when compiling with -O3
(thanks to godbolt.org).

Let's leave it as is for now, but I would be for dropping this strange
construct, only used with the virtio ring packed layout iirc.


-- 
David Marchand