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* [Bug target/95471] New: vrndvq_f32 not supported on armv8 @ 2020-06-02 1:50 evan@coeus-group.com 2020-06-02 8:43 ` [Bug target/95471] " ktkachov at gcc dot gnu.org 2020-06-02 17:50 ` evan@coeus-group.com 0 siblings, 2 replies; 3+ messages in thread From: evan@coeus-group.com @ 2020-06-02 1:50 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95471 Bug ID: 95471 Summary: vrndvq_f32 not supported on armv8 Product: gcc Version: 9.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: target Assignee: unassigned at gcc dot gnu.org Reporter: evan@coeus-group.com Target Milestone: --- With -march=armv8-a -mfpu=neon, arm_neon.h exposes vrndnq_f32, but the intrinsic used to implement it (__builtin_neon_vrintnv4sf) emits an "error: this builtin is not supported for this target". Here is a trivial test case: #include <arm_neon.h> #if defined(__ARM_NEON) float32x4_t foo(float32x4_t a) { return vrndnq_f32(a); } #endif On Compiler Explorer: https://godbolt.org/z/ThfJQe Relevant documentation from ARM: <https://developer.arm.com/architectures/instruction-sets/simd-isas/neon/intrinsics?search=vrndnq_f32>. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/95471] vrndvq_f32 not supported on armv8 2020-06-02 1:50 [Bug target/95471] New: vrndvq_f32 not supported on armv8 evan@coeus-group.com @ 2020-06-02 8:43 ` ktkachov at gcc dot gnu.org 2020-06-02 17:50 ` evan@coeus-group.com 1 sibling, 0 replies; 3+ messages in thread From: ktkachov at gcc dot gnu.org @ 2020-06-02 8:43 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95471 ktkachov at gcc dot gnu.org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |INVALID CC| |ktkachov at gcc dot gnu.org --- Comment #1 from ktkachov at gcc dot gnu.org --- -mfpu=neon doesn't support the Neon features from Armv8-A. The recommended way is to use -mfpu=auto and use an appropriate -mcpu or -march option. In this case, using -march=armv8-a+simd -mfpu=auto generates the instruction. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug target/95471] vrndvq_f32 not supported on armv8 2020-06-02 1:50 [Bug target/95471] New: vrndvq_f32 not supported on armv8 evan@coeus-group.com 2020-06-02 8:43 ` [Bug target/95471] " ktkachov at gcc dot gnu.org @ 2020-06-02 17:50 ` evan@coeus-group.com 1 sibling, 0 replies; 3+ messages in thread From: evan@coeus-group.com @ 2020-06-02 17:50 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95471 --- Comment #2 from Evan Nemerson <evan@coeus-group.com> --- In that case shouldn't the header be adjusted to not define the vrndvq_f32 function unless it is enabled? It is already guarded by a check for __ARM_ARCH >= 8 (see <https://github.com/gcc-mirror/gcc/blob/95827968e5f3e472bbef0ad8b65b0a7537c9cee3/gcc/config/arm/arm_neon.h#L1757>, but obviously that isn't sufficient. If nothing else it would help document the actual requirements, which would be great since the flags and macros on ARM are a bit of a mess. ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-06-02 17:50 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-06-02 1:50 [Bug target/95471] New: vrndvq_f32 not supported on armv8 evan@coeus-group.com 2020-06-02 8:43 ` [Bug target/95471] " ktkachov at gcc dot gnu.org 2020-06-02 17:50 ` evan@coeus-group.com
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