According to https://godbolt.org/z/q5rME1naY and acle, we found that
there are different SVE conversion behaviours between clang and gcc. It turns
out that llvm does not handle SVE predicates width properly.
This patch 1) checks SVE predicates width rightly with svbool_t type.
2) removes warning on svbool_t VLST <-> VLAT/GNUT conversion.
3) disables VLST <-> VLAT/GNUT conversion between SVE vectors and predicates
due to different width.
Differential Revision: https://reviews.llvm.org/D106333
Previously, lax conversions were only allowed between SVE vector-length
agnostic types and vector-length specific types. This meant that code
such as the following:
#include <arm_sve.h>
#define N __ARM_FEATURE_SVE_BITS
#define FIXED_ATTR __attribute__ ((vector_size (N/8)))
typedef float fixed_float32_t FIXED_ATTR;
void foo() {
fixed_float32_t fs32;
svfloat64_t s64;
fs32 = s64;
}
was not allowed.
This patch makes a minor change to areLaxCompatibleSveTypes to allow for
lax conversions to be performed between SVE vector-length agnostic types
and GNU vectors.
Differential Revision: https://reviews.llvm.org/D91696
Lax vector conversions was behaving incorrectly for implicit casts
between scalable and fixed-length vector types. For example, this:
#include <arm_sve.h>
#define N __ARM_FEATURE_SVE_BITS
#define FIXED_ATTR __attribute__((arm_sve_vector_bits(N)))
typedef svfloat32_t fixed_float32_t FIXED_ATTR;
void allowed_depending() {
fixed_float32_t fs32;
svfloat64_t s64;
fs32 = s64;
}
... would fail because the vectors have differing lane sizes. This patch
implements the correct behaviour for
-flax-vector-conversions={none,all,integer}. Specifically:
- -flax-vector-conversions=none prevents all lax vector conversions
between scalable and fixed-sized vectors.
- -flax-vector-conversions=integer allows lax vector conversions between
scalable and fixed-size vectors whose element types are integers.
- -flax-vector-conversions=all allows all lax vector conversions between
scalable and fixed-size vectors (including those with floating point
element types).
The implicit conversions are implemented as bitcasts.
Reviewed By: fpetrogalli
Differential Revision: https://reviews.llvm.org/D91067
Jun Ma