diff options
Diffstat (limited to 'gcc/config/aarch64/aarch64.c')
| -rw-r--r-- | gcc/config/aarch64/aarch64.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c index 1d48108516d..d3d7d1e60d6 100644 --- a/gcc/config/aarch64/aarch64.c +++ b/gcc/config/aarch64/aarch64.c @@ -8316,7 +8316,8 @@ aarch64_cannot_change_mode_class (enum machine_mode from, /* Limited combinations of subregs are safe on FPREGs. Particularly, 1. Vector Mode to Scalar mode where 1 unit of the vector is accessed. 2. Scalar to Scalar for integer modes or same size float modes. - 3. Vector to Vector modes. */ + 3. Vector to Vector modes. + 4. On little-endian only, Vector-Structure to Vector modes. */ if (GET_MODE_SIZE (from) > GET_MODE_SIZE (to)) { if (aarch64_vector_mode_supported_p (from) @@ -8332,11 +8333,41 @@ aarch64_cannot_change_mode_class (enum machine_mode from, if (aarch64_vector_mode_supported_p (from) && aarch64_vector_mode_supported_p (to)) return false; + + /* Within an vector structure straddling multiple vector registers + we are in a mixed-endian representation. As such, we can't + easily change modes for BYTES_BIG_ENDIAN. Otherwise, we can + switch between vectors and vector structures cheaply. */ + if (!BYTES_BIG_ENDIAN) + if ((aarch64_vector_mode_supported_p (from) + && aarch64_vect_struct_mode_p (to)) + || (aarch64_vector_mode_supported_p (to) + && aarch64_vect_struct_mode_p (from))) + return false; } return true; } +/* Implement MODES_TIEABLE_P. */ + +bool +aarch64_modes_tieable_p (enum machine_mode mode1, enum machine_mode mode2) +{ + if (GET_MODE_CLASS (mode1) == GET_MODE_CLASS (mode2)) + return true; + + /* We specifically want to allow elements of "structure" modes to + be tieable to the structure. This more general condition allows + other rarer situations too. */ + if (TARGET_SIMD + && aarch64_vector_mode_p (mode1) + && aarch64_vector_mode_p (mode2)) + return true; + + return false; +} + #undef TARGET_ADDRESS_COST #define TARGET_ADDRESS_COST aarch64_address_cost |