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| author | Joel Sing <joel@sing.id.au> | 2020-02-26 04:01:29 +1100 |
|---|---|---|
| committer | Joel Sing <joel@sing.id.au> | 2020-02-26 18:00:53 +0000 |
| commit | 025a4faf5fd70b8be4a77d19762eb2b4da8754b0 (patch) | |
| tree | 1d9216724ceee9b848a44cceffb7dead05d028bd /src/cmd/compile/internal/ssa/gen/RISCV64.rules | |
| parent | c27dd0c9e581edb71c834e161db6a920ca239997 (diff) | |
| download | go-025a4faf5fd70b8be4a77d19762eb2b4da8754b0.tar.gz go-025a4faf5fd70b8be4a77d19762eb2b4da8754b0.zip | |
cmd/compile: simplify Slicemask on riscv64
Slicemask can be performed with three immediate instructions, rather than the
six currently in use.
Change-Id: I3f8ca2d5affd1403db8fa79b356f248e6e9332c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/220923
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Diffstat (limited to 'src/cmd/compile/internal/ssa/gen/RISCV64.rules')
| -rw-r--r-- | src/cmd/compile/internal/ssa/gen/RISCV64.rules | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules index 1ffb9575e0..316e5f3726 100644 --- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules +++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules @@ -141,8 +141,7 @@ // For positive x, bit 63 of x-1 is always 0, so the result is -1. // For zero x, bit 63 of x-1 is 1, so the result is 0. // -// TODO(prattmic): Use XORconst etc instead of XOR (MOVDconst). -(Slicemask <t> x) -> (XOR (MOVDconst [-1]) (SRA <t> (SUB <t> x (MOVDconst [1])) (MOVDconst [63]))) +(Slicemask <t> x) -> (XORI [-1] (SRAI <t> [63] (ADDI <t> [-1] x))) // Truncations // We ignore the unused high parts of registers, so truncates are just copies. |