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| author | Joel Sing <joel@sing.id.au> | 2020-03-02 04:24:35 +1100 |
|---|---|---|
| committer | Joel Sing <joel@sing.id.au> | 2020-03-03 12:03:48 +0000 |
| commit | d28b8524a4d5d86d7b1e2df790abff6244de2a00 (patch) | |
| tree | 3a5ae42b83c1f4c0323018e539537932f00f9892 /src/cmd/compile/internal/ssa/gen/RISCV64.rules | |
| parent | bd6f4cd886458bb4ab1f492202fa2b499dcfc6f7 (diff) | |
| download | go-d28b8524a4d5d86d7b1e2df790abff6244de2a00.tar.gz go-d28b8524a4d5d86d7b1e2df790abff6244de2a00.zip | |
cmd/compile: optimize subtraction of zero on riscv64
Change-Id: I9a994b01e9fecb13077c30df4b7677d40d179cce
Reviewed-on: https://go-review.googlesource.com/c/go/+/221681
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 | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules index 3fd482b50c..9c1169dc67 100644 --- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules +++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules @@ -467,5 +467,14 @@ (SUB x (MOVWconst [val])) && is32Bit(-val) -> (ADDI [-val] x) (SUB x (MOVDconst [val])) && is32Bit(-val) -> (ADDI [-val] x) +// Subtraction of zero. +(SUB x (MOVBconst [0])) -> x +(SUB x (MOVHconst [0])) -> x +(SUB x (MOVWconst [0])) -> x +(SUB x (MOVDconst [0])) -> x + +// Subtraction of zero with sign extension. +(SUBW x (MOVWconst [0])) -> (ADDIW [0] x) + // remove redundant *const ops (ADDI [0] x) -> x |