cmd/compile: resolve known outcomes for SLTI/SLTIU on riscv64

When SLTI/SLTIU is used with ANDI/ORI, it may be possible to determine the
outcome based on the values of the immediates. Resolve these cases.

Improves code generation for various shift operations.

While here, sort tests by architecture to improve readability and ease
future maintenance.

Change-Id: I87e71e016a0e396a928e7d6389a2df61583dfd8d
Reviewed-on: https://go-review.googlesource.com/c/go/+/428217
Reviewed-by: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Jenny Rakoczy <jenny@golang.org>
Reviewed-by: Jenny Rakoczy <jenny@golang.org>
Run-TryBot: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Auto-Submit: Jenny Rakoczy <jenny@golang.org>

diff --git a/src/cmd/compile/internal/ssa/gen/RISCV64.rules b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
index e37c7b7899313f7aa81fbdb1e3716de01b75afec..c2f1c16b6bc68044e06ce11e5a5ae926c06dcd27 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/RISCV64.rules
+++ b/src/cmd/compile/internal/ssa/gen/RISCV64.rules
@@ -801,10 +801,17 @@
 (SLTI  [x] (MOVDconst [y])) => (MOVDconst [b2i(int64(y) < int64(x))])
 (SLTIU [x] (MOVDconst [y])) => (MOVDconst [b2i(uint64(y) < uint64(x))])
 
-(SLT x x)  => (MOVDconst [0])
+// SLTI/SLTIU with known outcomes.
+(SLTI  [x] (ANDI [y] _)) && y >= 0 && int64(y) < int64(x) => (MOVDconst [1])
+(SLTIU [x] (ANDI [y] _)) && y >= 0 && uint64(y) < uint64(x) => (MOVDconst [1])
+(SLTI  [x] (ORI  [y] _)) && y >= 0 && int64(y) >= int64(x) => (MOVDconst [0])
+(SLTIU [x] (ORI  [y] _)) && y >= 0 && uint64(y) >= uint64(x) => (MOVDconst [0])
+
+// SLT/SLTU with known outcomes.
+(SLT  x x) => (MOVDconst [0])
 (SLTU x x) => (MOVDconst [0])
 
-// deadcode for LoweredMuluhilo
+// Deadcode for LoweredMuluhilo
 (Select0 m:(LoweredMuluhilo x y)) && m.Uses == 1 => (MULHU x y)
 (Select1 m:(LoweredMuluhilo x y)) && m.Uses == 1 => (MUL x y)
 

diff --git a/src/cmd/compile/internal/ssa/rewriteRISCV64.go b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
index 6f949707a1deef99bd99a245935f2eddadb24d20..097232ab185ea6a2ed9e7ed29d17a78ac651b4ac 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewriteRISCV64.go
+++ b/src/cmd/compile/internal/ssa/rewriteRISCV64.go
@@ -5530,6 +5530,38 @@ func rewriteValueRISCV64_OpRISCV64SLTI(v *Value) bool {
                v.AuxInt = int64ToAuxInt(b2i(int64(y) < int64(x)))
                return true
        }
+       // match: (SLTI [x] (ANDI [y] _))
+       // cond: y >= 0 && int64(y) < int64(x)
+       // result: (MOVDconst [1])
+       for {
+               x := auxIntToInt64(v.AuxInt)
+               if v_0.Op != OpRISCV64ANDI {
+                       break
+               }
+               y := auxIntToInt64(v_0.AuxInt)
+               if !(y >= 0 && int64(y) < int64(x)) {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(1)
+               return true
+       }
+       // match: (SLTI [x] (ORI [y] _))
+       // cond: y >= 0 && int64(y) >= int64(x)
+       // result: (MOVDconst [0])
+       for {
+               x := auxIntToInt64(v.AuxInt)
+               if v_0.Op != OpRISCV64ORI {
+                       break
+               }
+               y := auxIntToInt64(v_0.AuxInt)
+               if !(y >= 0 && int64(y) >= int64(x)) {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(0)
+               return true
+       }
        return false
 }
 func rewriteValueRISCV64_OpRISCV64SLTIU(v *Value) bool {
@@ -5546,6 +5578,38 @@ func rewriteValueRISCV64_OpRISCV64SLTIU(v *Value) bool {
                v.AuxInt = int64ToAuxInt(b2i(uint64(y) < uint64(x)))
                return true
        }
+       // match: (SLTIU [x] (ANDI [y] _))
+       // cond: y >= 0 && uint64(y) < uint64(x)
+       // result: (MOVDconst [1])
+       for {
+               x := auxIntToInt64(v.AuxInt)
+               if v_0.Op != OpRISCV64ANDI {
+                       break
+               }
+               y := auxIntToInt64(v_0.AuxInt)
+               if !(y >= 0 && uint64(y) < uint64(x)) {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(1)
+               return true
+       }
+       // match: (SLTIU [x] (ORI [y] _))
+       // cond: y >= 0 && uint64(y) >= uint64(x)
+       // result: (MOVDconst [0])
+       for {
+               x := auxIntToInt64(v.AuxInt)
+               if v_0.Op != OpRISCV64ORI {
+                       break
+               }
+               y := auxIntToInt64(v_0.AuxInt)
+               if !(y >= 0 && uint64(y) >= uint64(x)) {
+                       break
+               }
+               v.reset(OpRISCV64MOVDconst)
+               v.AuxInt = int64ToAuxInt(0)
+               return true
+       }
        return false
 }
 func rewriteValueRISCV64_OpRISCV64SLTU(v *Value) bool {

diff --git a/test/codegen/shift.go b/test/codegen/shift.go
index 5a2391358c31d57863299b1b57febaadb78f3163..c82566bb100d91a2116290869e0232001dbd1f23 100644 (file)
--- a/test/codegen/shift.go
+++ b/test/codegen/shift.go
@@ -11,65 +11,65 @@ package codegen
 // ------------------ //
 
 func lshConst64x64(v int64) int64 {
-       // riscv64:"SLLI",-"AND",-"SLTIU"
-       // ppc64le:"SLD"
        // ppc64:"SLD"
+       // ppc64le:"SLD"
+       // riscv64:"SLLI",-"AND",-"SLTIU"
        return v << uint64(33)
 }
 
 func rshConst64Ux64(v uint64) uint64 {
-       // riscv64:"SRLI",-"AND",-"SLTIU"
-       // ppc64le:"SRD"
        // ppc64:"SRD"
+       // ppc64le:"SRD"
+       // riscv64:"SRLI",-"AND",-"SLTIU"
        return v >> uint64(33)
 }
 
 func rshConst64x64(v int64) int64 {
-       // riscv64:"SRAI",-"OR",-"SLTIU"
-       // ppc64le:"SRAD"
        // ppc64:"SRAD"
+       // ppc64le:"SRAD"
+       // riscv64:"SRAI",-"OR",-"SLTIU"
        return v >> uint64(33)
 }
 
 func lshConst32x64(v int32) int32 {
-       // riscv64:"SLLI",-"AND",-"SLTIU"
-       // ppc64le:"SLW"
        // ppc64:"SLW"
+       // ppc64le:"SLW"
+       // riscv64:"SLLI",-"AND",-"SLTIU"
        return v << uint64(29)
 }
 
 func rshConst32Ux64(v uint32) uint32 {
-       // riscv64:"SRLI",-"AND",-"SLTIU"
-       // ppc64le:"SRW"
        // ppc64:"SRW"
+       // ppc64le:"SRW"
+       // riscv64:"SRLI",-"AND",-"SLTIU"
        return v >> uint64(29)
 }
 
 func rshConst32x64(v int32) int32 {
-       // riscv64:"SRAI",-"OR",-"SLTIU"
-       // ppc64le:"SRAW"
        // ppc64:"SRAW"
+       // ppc64le:"SRAW"
+       // riscv64:"SRAI",-"OR",-"SLTIU"
        return v >> uint64(29)
 }
 
 func lshConst64x32(v int64) int64 {
-       // riscv64:"SLLI",-"AND",-"SLTIU"
-       // ppc64le:"SLD"
        // ppc64:"SLD"
+       // ppc64le:"SLD"
+       // riscv64:"SLLI",-"AND",-"SLTIU"
        return v << uint32(33)
 }
 
 func rshConst64Ux32(v uint64) uint64 {
-       // riscv64:"SRLI",-"AND",-"SLTIU"
-       // ppc64le:"SRD"
        // ppc64:"SRD"
+       // ppc64le:"SRD"
+       // riscv64:"SRLI",-"AND",-"SLTIU"
        return v >> uint32(33)
 }
 
 func rshConst64x32(v int64) int64 {
-       // riscv64:"SRAI",-"OR",-"SLTIU"
-       // ppc64le:"SRAD"
        // ppc64:"SRAD"
+       // ppc64le:"SRAD"
+       // riscv64:"SRAI",-"OR",-"SLTIU"
        return v >> uint32(33)
 }
 
@@ -78,90 +78,90 @@ func rshConst64x32(v int64) int64 {
 // ------------------ //
 
 func lshMask64x64(v int64, s uint64) int64 {
+       // arm64:"LSL",-"AND"
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
        // riscv64:"SLL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSL",-"AND"
        return v << (s & 63)
 }
 
 func rshMask64Ux64(v uint64, s uint64) uint64 {
+       // arm64:"LSR",-"AND",-"CSEL"
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
        // riscv64:"SRL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSR",-"AND",-"CSEL"
        return v >> (s & 63)
 }
 
 func rshMask64x64(v int64, s uint64) int64 {
+       // arm64:"ASR",-"AND",-"CSEL"
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-ORN",-"ISEL"
        // riscv64:"SRA",-"OR",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"ASR",-"AND",-"CSEL"
        return v >> (s & 63)
 }
 
 func lshMask32x64(v int32, s uint64) int32 {
+       // arm64:"LSL",-"AND"
        // ppc64:"ISEL",-"ORN"
        // ppc64le:"ISEL",-"ORN"
-       // riscv64:"SLL","AND","SLTIU"
+       // riscv64:"SLL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSL",-"AND"
        return v << (s & 63)
 }
 
 func rshMask32Ux64(v uint32, s uint64) uint32 {
+       // arm64:"LSR",-"AND"
        // ppc64:"ISEL",-"ORN"
        // ppc64le:"ISEL",-"ORN"
-       // riscv64:"SRL","AND","SLTIU"
+       // riscv64:"SRL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSR",-"AND"
        return v >> (s & 63)
 }
 
 func rshMask32x64(v int32, s uint64) int32 {
+       // arm64:"ASR",-"AND"
        // ppc64:"ISEL",-"ORN"
        // ppc64le:"ISEL",-"ORN"
-       // riscv64:"SRA","OR","SLTIU"
+       // riscv64:"SRA",-"OR",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"ASR",-"AND"
        return v >> (s & 63)
 }
 
 func lshMask64x32(v int64, s uint32) int64 {
+       // arm64:"LSL",-"AND"
        // ppc64:"ANDCC",-"ORN"
        // ppc64le:"ANDCC",-"ORN"
        // riscv64:"SLL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSL",-"AND"
        return v << (s & 63)
 }
 
 func rshMask64Ux32(v uint64, s uint32) uint64 {
+       // arm64:"LSR",-"AND",-"CSEL"
        // ppc64:"ANDCC",-"ORN"
        // ppc64le:"ANDCC",-"ORN"
        // riscv64:"SRL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"LSR",-"AND",-"CSEL"
        return v >> (s & 63)
 }
 
 func rshMask64x32(v int64, s uint32) int64 {
+       // arm64:"ASR",-"AND",-"CSEL"
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
        // riscv64:"SRA",-"OR",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
-       // arm64:"ASR",-"AND",-"CSEL"
        return v >> (s & 63)
 }
 
 func lshMask64x32Ext(v int64, s int32) int64 {
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
-       // riscv64:"SLL","AND","SLTIU"
+       // riscv64:"SLL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
        return v << uint(s&63)
 }
@@ -169,7 +169,7 @@ func lshMask64x32Ext(v int64, s int32) int64 {
 func rshMask64Ux32Ext(v uint64, s int32) uint64 {
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
-       // riscv64:"SRL","AND","SLTIU"
+       // riscv64:"SRL",-"AND\t",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
        return v >> uint(s&63)
 }
@@ -177,7 +177,7 @@ func rshMask64Ux32Ext(v uint64, s int32) uint64 {
 func rshMask64x32Ext(v int64, s int32) int64 {
        // ppc64:"ANDCC",-"ORN",-"ISEL"
        // ppc64le:"ANDCC",-"ORN",-"ISEL"
-       // riscv64:"SRA","OR","SLTIU"
+       // riscv64:"SRA",-"OR",-"SLTIU"
        // s390x:-"RISBGZ",-"AND",-"LOCGR"
        return v >> uint(s&63)
 }