diff options
| author | Giovanni Bajo <rasky@develer.com> | 2018-03-10 11:17:05 +0100 |
|---|---|---|
| committer | Giovanni Bajo <rasky@develer.com> | 2018-03-13 23:21:38 +0000 |
| commit | eb44b8635cc774d0f2b2f96637116a5b41943bc5 (patch) | |
| tree | b0291c16f80a27d456546bfb1239419b30c3fdbd /src | |
| parent | e601c079082658399445c2698f7e5cb60d23db29 (diff) | |
| download | go-eb44b8635cc774d0f2b2f96637116a5b41943bc5.tar.xz | |
cmd/compile: remove BTQconst rule
This rule is meant for code optimization, but it makes other rules
potentially more complex, as they need to cope with the fact that
a 32-bit op (BTLconst) can appear everywhere a 64-bit rule maches.
Move the optimization to opcode expansion instead. Tests will be
added in following CL.
Change-Id: Ica5ef291e7963c4af17c124d4a2869e6c8f7b0c7
Reviewed-on: https://go-review.googlesource.com/99995
Reviewed-by: Keith Randall <khr@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/compile/internal/amd64/ssa.go | 14 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/gen/AMD64.rules | 3 | ||||
| -rw-r--r-- | src/cmd/compile/internal/ssa/rewriteAMD64.go | 19 |
3 files changed, 12 insertions, 24 deletions
diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go index fedc525463..6b8fe875a4 100644 --- a/src/cmd/compile/internal/amd64/ssa.go +++ b/src/cmd/compile/internal/amd64/ssa.go @@ -562,8 +562,18 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) { p.From.Reg = v.Args[0].Reg() p.To.Type = obj.TYPE_CONST p.To.Offset = v.AuxInt - case ssa.OpAMD64TESTQconst, ssa.OpAMD64TESTLconst, ssa.OpAMD64TESTWconst, ssa.OpAMD64TESTBconst, - ssa.OpAMD64BTLconst, ssa.OpAMD64BTQconst: + case ssa.OpAMD64BTLconst, ssa.OpAMD64BTQconst: + op := v.Op + if op == ssa.OpAMD64BTQconst && v.AuxInt < 32 { + // Emit 32-bit version because it's shorter + op = ssa.OpAMD64BTLconst + } + p := s.Prog(op.Asm()) + p.From.Type = obj.TYPE_CONST + p.From.Offset = v.AuxInt + p.To.Type = obj.TYPE_REG + p.To.Reg = v.Args[0].Reg() + case ssa.OpAMD64TESTQconst, ssa.OpAMD64TESTLconst, ssa.OpAMD64TESTWconst, ssa.OpAMD64TESTBconst: p := s.Prog(v.Op.Asm()) p.From.Type = obj.TYPE_CONST p.From.Offset = v.AuxInt diff --git a/src/cmd/compile/internal/ssa/gen/AMD64.rules b/src/cmd/compile/internal/ssa/gen/AMD64.rules index ffac45bf66..cabc8f4d20 100644 --- a/src/cmd/compile/internal/ssa/gen/AMD64.rules +++ b/src/cmd/compile/internal/ssa/gen/AMD64.rules @@ -666,9 +666,6 @@ (XORLconst [1] (SETBE x)) -> (SETA x) (XORLconst [1] (SETA x)) -> (SETBE x) -// Convert BTQconst to BTLconst if possible. It has a shorter encoding. -(BTQconst [c] x) && c < 32 -> (BTLconst [c] x) - // Special case for floating point - LF/LEF not generated (NE (TESTB (SETGF cmp) (SETGF cmp)) yes no) -> (UGT cmp yes no) (NE (TESTB (SETGEF cmp) (SETGEF cmp)) yes no) -> (UGE cmp yes no) diff --git a/src/cmd/compile/internal/ssa/rewriteAMD64.go b/src/cmd/compile/internal/ssa/rewriteAMD64.go index eb2489ac77..9d1d36d14c 100644 --- a/src/cmd/compile/internal/ssa/rewriteAMD64.go +++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go @@ -53,8 +53,6 @@ func rewriteValueAMD64(v *Value) bool { return rewriteValueAMD64_OpAMD64ANDQmem_0(v) case OpAMD64BSFQ: return rewriteValueAMD64_OpAMD64BSFQ_0(v) - case OpAMD64BTQconst: - return rewriteValueAMD64_OpAMD64BTQconst_0(v) case OpAMD64CMOVLCC: return rewriteValueAMD64_OpAMD64CMOVLCC_0(v) case OpAMD64CMOVLCS: @@ -3336,23 +3334,6 @@ func rewriteValueAMD64_OpAMD64BSFQ_0(v *Value) bool { } return false } -func rewriteValueAMD64_OpAMD64BTQconst_0(v *Value) bool { - // match: (BTQconst [c] x) - // cond: c < 32 - // result: (BTLconst [c] x) - for { - c := v.AuxInt - x := v.Args[0] - if !(c < 32) { - break - } - v.reset(OpAMD64BTLconst) - v.AuxInt = c - v.AddArg(x) - return true - } - return false -} func rewriteValueAMD64_OpAMD64CMOVLCC_0(v *Value) bool { // match: (CMOVLCC x y (InvertFlags cond)) // cond: |