https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101284
Bug ID: 101284
Summary: conflicting arch/fpu result in unexpected preprocessor
defines
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: clyon at gcc dot gnu.org
Target Milestone: ---
Compiling with -march=armv8.1-m.main+mve.fp -mfpu=neon-fp16 -mfloat-abi=softfp
produces no warning and generates the following defines:
#define __ARM_NEON__ 1
#define __ARM_NEON 1
#define __ARM_NEON_FP 6
#define __ARM_FEATURE_MVE 3
which I didn't expect.
This also means that TARGET_HAVE_MVE is defined in the compiler as well as
TARGET_NEON. So vectorization code that has to do different things for Neon and
MVE can quite easily ICE if you provide all these flags on the command-line.
(I wanted to compare vectorization with MVE and Neon on one testcase and hoped
to override the MVE FPU by just adding -mfpu=neon-fp16 and the end of the
command-line).
