... and give more guidance to users.
If specifying -msve-vector-bits on a non-SVE target, clang would say:
error: '-msve-vector-bits' is not supported without SVE enabled
1. The driver lacks logic for "implied features".
This would result in this error being raised for -march=...+sve2,
even though +sve2 implies +sve.
2. Feature implication is well modelled in LLVM, so push the error down
the stack.
3. Hint to the user what flag they need to consider setting.
Now clang fails later, when the feature is used, saying:
aarch64-sve-vector-bits.c:42:41: error: 'arm_sve_vector_bits' attribute is not supported on targets missing 'sve'; specify an appropriate -march= or -mcpu=
typedef svint32_t noflag __attribute__((arm_sve_vector_bits(256)));
Move clang/test/Sema/{neon => arm}-vector-types-support.c and put tests for
this warning together in one place.
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D92487
No real action is taken for a value of scalable but it provides a
route to disable an earlier specification and is effectively its
default value when omitted.
Patch also removes an "unused variable" warning.
Differential Revision: https://reviews.llvm.org/D84021
Summary:
This patch implements parsing support for the 'arm_sve_vector_bits' type
attribute, defined by the Arm C Language Extensions (ACLE, version 00bet5,
section 3.7.3) for SVE [1].
The purpose of this attribute is to define fixed-length (VLST) versions
of existing sizeless types (VLAT). For example:
#if __ARM_FEATURE_SVE_BITS==512
typedef svint32_t fixed_svint32_t __attribute__((arm_sve_vector_bits(512)));
#endif
Creates a type 'fixed_svint32_t' that is a fixed-length version of
'svint32_t' that is normal-sized (rather than sizeless) and contains
exactly 512 bits. Unlike 'svint32_t', this type can be used in places
such as structs and arrays where sizeless types can't.
Implemented in this patch is the following:
* Defined and tested attribute taking single argument.
* Checks the argument is an integer constant expression.
* Attribute can only be attached to a single SVE vector or predicate
type, excluding tuple types such as svint32x4_t.
* Added the `-msve-vector-bits=<bits>` flag. When specified the
`__ARM_FEATURE_SVE_BITS__EXPERIMENTAL` macro is defined.
* Added a language option to store the vector size specified by the
`-msve-vector-bits=<bits>` flag. This is used to validate `N ==
__ARM_FEATURE_SVE_BITS`, where N is the number of bits passed to the
attribute and `__ARM_FEATURE_SVE_BITS` is the feature macro defined under
the same flag.
The `__ARM_FEATURE_SVE_BITS` macro will be made non-experimental in the final
patch of the series.
[1] https://developer.arm.com/documentation/100987/latest
This is patch 1/4 of a patch series.
Reviewers: sdesmalen, rsandifo-arm, efriedma, ctetreau, cameron.mcinally, rengolin, aaron.ballman
Reviewed By: sdesmalen, aaron.ballman
Differential Revision: https://reviews.llvm.org/D83550
Peter Waller