https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97802
Bug ID: 97802
Summary: [AArch64] Incorrect documentation for Arm64 NEON
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: spop at gcc dot gnu.org
Target Milestone: ---
The following text in doc/invoke.texi seems to be outdated. To avoid confusion
the text needs to be more specific on which NEON implementations it applies:
"If the selected floating-point hardware includes the NEON extension
(e.g.@: @option{-mfpu=neon}), note that floating-point
operations are not generated by GCC's auto-vectorization pass unless
@option{-funsafe-math-optimizations} is also specified. This is
because NEON hardware does not fully implement the IEEE 754 standard for
floating-point arithmetic (in particular denormal values are treated as
zero), so the use of NEON instructions may lead to a loss of precision."
This used to be true for older NEON implementations.
NEON implementation in Armv8 and later is IEEE 754 compliant.
