Hi Tim and other reviewers,
Those are 2 patches for LLVM and Clang to fix UQSHL/SQSHL by constant can not be selected. The simply intrinsic call:
vqshld_s64(a, 36) // a is a int64_t
will cause build failure.
The root cause is that 2 different pattern match types are used for the following 2 intrinsics:
int64_t vqshld_n_s64(int64_t a, const int n) SQSHL Dd,Dn,#n int64_t vqshld_s64(int64_t a, int64_t b) SQSHL Dd,Dn,Dm
vqshld_n_s64 uses int64x1_t for arguments and return value. vqshld_s64 uses int64_t. If the second argument of vqshld_s64 is a constant, it will also try to generate a SQSHL by contant instrution, i.e the first kind of instruction "SQSHL Dd,Dn,#n", not "SQSHL Dd,Dn,Dm". As there is only a pattern for v1i64, not i64, there is a cannot select failure.
To fix this, we can simply add a pattern about i64 to match SQSHL by constant (The LLVM patch). But except that, I also think it is not reasonable to use int64x1_t for "int64_t vqshld_n_s64(int64_t a, const int n)", as it is originally int64_t, why we transfer int64_t to int64xt_t to match. So I also modify the Clang to use int64_t/uint64_t instead of transfering to int64x1_t/uint64x1_t (The Clang patch).
I only add two test cases about vqshld_s64 and vqshld_u64 with constant shift amount, as there are already other test cases for other situations.