AArch64: Lower intrinsics shift to GIMPLE when possible.
This lowers shifts to GIMPLE when the C interpretations of the shift operations
matches that of AArch64.
In C shifting right by BITSIZE is undefined, but the behavior is defined in
AArch64. Additionally negative shifts lefts are undefined for the register
variant of the instruction (SSHL, USHL) as being right shifts.
Since we have a right shift by immediate I rewrite those cases into right shifts
So:
int64x1_t foo3 (int64x1_t a)
{
return vshl_s64 (a, vdup_n_s64(-6));
}
produces:
foo3:
sshr d0, d0, 6
ret
instead of:
foo3:
mov x0, -6
fmov d1, x0
sshl d0, d0, d1
ret
This behavior isn't specifically mentioned for a left shift by immediate, but I
believe that only the case because we do have a right shift by immediate but not
a right shift by register. As such I do the same for left shift by immediate.
gcc/ChangeLog:
* config/aarch64/aarch64-builtins.c
(aarch64_general_gimple_fold_builtin): Add ashl, sshl, ushl, ashr,
ashr_simd, lshr, lshr_simd.
* config/aarch64/aarch64-simd-builtins.def (lshr): Use USHIFTIMM.
* config/aarch64/arm_neon.h (vshr_n_u8, vshr_n_u16, vshr_n_u32,
vshrq_n_u8, vshrq_n_u16, vshrq_n_u32, vshrq_n_u64): Fix type hack.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-1.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-2.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-3.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-4.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-5.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-6.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-7.c: New test.
* gcc.target/aarch64/advsimd-intrinsics/vshl-opt-8.c: New test.
* gcc.target/aarch64/signbit-2.c: New test.
12 files changed: