cmd/compile: add generic simplifications on riscv64

file      before    after     Δ       %
addr2line 3636263   3636215   -48     -0.001%
asm       6318110   6317966   -144    -0.002%
buildid   3463352   3463224   -128    -0.004%
cgo       5672502   5672214   -288    -0.005%
compile   26904997  26905719  +722    +0.003%
cover     6405603   6405467   -136    -0.002%
dist      4092630   4092494   -136    -0.003%
doc       9728281   9723977   -4304   -0.044%
fix       4014891   4014835   -56     -0.001%
link      8327674   8327426   -248    -0.003%
nm        3628718   3628494   -224    -0.006%
objdump   5951778   5951626   -152    -0.003%
pack      2896080   2896040   -40     -0.001%
pprof     17596796  17591908  -4888   -0.028%
test2json 3346622   3346566   -56     -0.002%
trace     16179738  16175706  -4032   -0.025%
vet       9603472   9603264   -208    -0.002%
total     156070021 156055655 -14366  -0.009%

Change-Id: Ie4a79a3c410eb79155ce2418ae64fa670d1ccd53
Reviewed-on: https://go-review.googlesource.com/c/go/+/673477
Reviewed-by: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>

diff --git a/src/cmd/compile/internal/ssa/_gen/RISCV64.rules b/src/cmd/compile/internal/ssa/_gen/RISCV64.rules
index 80061ada2cfdaf1864709a3b71637108c6fd7825..dc1cc97fb3cd05e306a7a7b83aadcdd64486fc11 100644 (file)
--- a/src/cmd/compile/internal/ssa/_gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/RISCV64.rules
@@ -743,6 +743,15 @@
 (ROL  x (NEG y)) => (ROR  x y)
 (ROLW x (NEG y)) => (RORW x y)
 
+// generic simplifications
+(ADD x (NEG y)) => (SUB x y)
+(SUB x (NEG y)) => (ADD x y)
+(SUB x x) => (MOVDconst [0])
+(AND x x) => x
+(OR  x x) => x
+(ORN x x) => (MOVDconst [-1])
+(XOR x x) => (MOVDconst [0])
+
 // Convert const subtraction into ADDI with negative immediate, where possible.
 (SUB x (MOVDconst [val])) && is32Bit(-val) => (ADDI [-val] x)
 (SUB <t> (MOVDconst [val]) y) && is32Bit(-val) => (NEG (ADDI <t> [-val] y))

diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
index 4e53ae5fe63f30070d21a9f69100c24a2288cbdd..95c6489a511be887f22620ee18f2248cdf77e454 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go
+++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
@@ -586,6 +586,8 @@ func rewriteValueRISCV64(v *Value) bool {
                return rewriteValueRISCV64_OpRISCV64OR(v)
        case OpRISCV64ORI:
                return rewriteValueRISCV64_OpRISCV64ORI(v)
+       case OpRISCV64ORN:
+               return rewriteValueRISCV64_OpRISCV64ORN(v)
        case OpRISCV64ROL:
                return rewriteValueRISCV64_OpRISCV64ROL(v)
        case OpRISCV64ROLW:
@@ -3522,6 +3524,21 @@ func rewriteValueRISCV64_OpRISCV64ADD(v *Value) bool {
                }
                break
        }
+       // match: (ADD x (NEG y))
+       // result: (SUB x y)
+       for {
+               for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+                       x := v_0
+                       if v_1.Op != OpRISCV64NEG {
+                               continue
+                       }
+                       y := v_1.Args[0]
+                       v.reset(OpRISCV64SUB)
+                       v.AddArg2(x, y)
+                       return true
+               }
+               break
+       }
        // match: (ADD (SLLI [1] x) y)
        // cond: buildcfg.GORISCV64 >= 22
        // result: (SH1ADD x y)
@@ -3672,6 +3689,16 @@ func rewriteValueRISCV64_OpRISCV64AND(v *Value) bool {
                }
                break
        }
+       // match: (AND x x)
+       // result: x
+       for {
+               x := v_0
+               if x != v_1 {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        return false
 }
 func rewriteValueRISCV64_OpRISCV64ANDI(v *Value) bool {
@@ -6396,6 +6423,16 @@ func rewriteValueRISCV64_OpRISCV64OR(v *Value) bool {
                }
                break
        }
+       // match: (OR x x)
+       // result: x
+       for {
+               x := v_0
+               if x != v_1 {
+                       break
+               }
+               v.copyOf(x)
+               return true
+       }
        return false
 }
 func rewriteValueRISCV64_OpRISCV64ORI(v *Value) bool {
@@ -6448,6 +6485,22 @@ func rewriteValueRISCV64_OpRISCV64ORI(v *Value) bool {
        }
        return false
 }
+func rewriteValueRISCV64_OpRISCV64ORN(v *Value) bool {
+       v_1 := v.Args[1]
+       v_0 := v.Args[0]
+       // match: (ORN x x)
+       // result: (MOVDconst [-1])
+       for {
+               x := v_0
+               if x != v_1 {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(-1)
+               return true
+       }
+       return false
+}
 func rewriteValueRISCV64_OpRISCV64ROL(v *Value) bool {
        v_1 := v.Args[1]
        v_0 := v.Args[0]
@@ -7093,6 +7146,29 @@ func rewriteValueRISCV64_OpRISCV64SUB(v *Value) bool {
        v_1 := v.Args[1]
        v_0 := v.Args[0]
        b := v.Block
+       // match: (SUB x (NEG y))
+       // result: (ADD x y)
+       for {
+               x := v_0
+               if v_1.Op != OpRISCV64NEG {
+                       break
+               }
+               y := v_1.Args[0]
+               v.reset(OpRISCV64ADD)
+               v.AddArg2(x, y)
+               return true
+       }
+       // match: (SUB x x)
+       // result: (MOVDconst [0])
+       for {
+               x := v_0
+               if x != v_1 {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(0)
+               return true
+       }
        // match: (SUB x (MOVDconst [val]))
        // cond: is32Bit(-val)
        // result: (ADDI [-val] x)
@@ -7204,6 +7280,17 @@ func rewriteValueRISCV64_OpRISCV64XOR(v *Value) bool {
                }
                break
        }
+       // match: (XOR x x)
+       // result: (MOVDconst [0])
+       for {
+               x := v_0
+               if x != v_1 {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(0)
+               return true
+       }
        return false
 }
 func rewriteValueRISCV64_OpRotateLeft16(v *Value) bool {