[dev.ssa] cmd/compile: SETcc instructions do not clobber flags

This reduces the number of flags spilled during
make.bash by > 90%.

I am working (slowly) on the rest.

Change-Id: I3c08ae228c33e2f726f615962996f0350c8d592b
Reviewed-on: https://go-review.googlesource.com/13813
Reviewed-by: David Chase <drchase@google.com>

diff --git a/src/cmd/compile/internal/ssa/gen/AMD64Ops.go b/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
index e633f82348bf34d56815012dddf8e61aaa399d14..b218c66a64a9e7dee440eac96f7644a4acd02a83 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
+++ b/src/cmd/compile/internal/ssa/gen/AMD64Ops.go
@@ -105,9 +105,10 @@ func init() {
                        clobbers: ax | flags}
                gp10 = regInfo{inputs: []regMask{gp}}
 
-               gp2flags = regInfo{inputs: []regMask{gpsp, gpsp}, outputs: flagsonly}
-               gp1flags = regInfo{inputs: []regMask{gpsp}, outputs: flagsonly}
-               flagsgp  = regInfo{inputs: flagsonly, outputs: gponly, clobbers: flags}
+               gp2flags  = regInfo{inputs: []regMask{gpsp, gpsp}, outputs: flagsonly}
+               gp1flags  = regInfo{inputs: []regMask{gpsp}, outputs: flagsonly}
+               flagsgp   = regInfo{inputs: flagsonly, outputs: gponly, clobbers: flags}
+               readflags = regInfo{inputs: flagsonly, outputs: gponly}
 
                gpload    = regInfo{inputs: []regMask{gpspsb, 0}, outputs: gponly}
                gploadidx = regInfo{inputs: []regMask{gpspsb, gpsp, 0}, outputs: gponly}
@@ -294,16 +295,16 @@ func init() {
                {name: "SBBLcarrymask", reg: flagsgp, asm: "SBBL"}, // (int32)(-1) if carry is set, 0 if carry is clear.
                // Note: SBBW and SBBB are subsumed by SBBL
 
-               {name: "SETEQ", reg: flagsgp, asm: "SETEQ"}, // extract == condition from arg0
-               {name: "SETNE", reg: flagsgp, asm: "SETNE"}, // extract != condition from arg0
-               {name: "SETL", reg: flagsgp, asm: "SETLT"},  // extract signed < condition from arg0
-               {name: "SETLE", reg: flagsgp, asm: "SETLE"}, // extract signed <= condition from arg0
-               {name: "SETG", reg: flagsgp, asm: "SETGT"},  // extract signed > condition from arg0
-               {name: "SETGE", reg: flagsgp, asm: "SETGE"}, // extract signed >= condition from arg0
-               {name: "SETB", reg: flagsgp, asm: "SETCS"},  // extract unsigned < condition from arg0
-               {name: "SETBE", reg: flagsgp, asm: "SETLS"}, // extract unsigned <= condition from arg0
-               {name: "SETA", reg: flagsgp, asm: "SETHI"},  // extract unsigned > condition from arg0
-               {name: "SETAE", reg: flagsgp, asm: "SETCC"}, // extract unsigned >= condition from arg0
+               {name: "SETEQ", reg: readflags, asm: "SETEQ"}, // extract == condition from arg0
+               {name: "SETNE", reg: readflags, asm: "SETNE"}, // extract != condition from arg0
+               {name: "SETL", reg: readflags, asm: "SETLT"},  // extract signed < condition from arg0
+               {name: "SETLE", reg: readflags, asm: "SETLE"}, // extract signed <= condition from arg0
+               {name: "SETG", reg: readflags, asm: "SETGT"},  // extract signed > condition from arg0
+               {name: "SETGE", reg: readflags, asm: "SETGE"}, // extract signed >= condition from arg0
+               {name: "SETB", reg: readflags, asm: "SETCS"},  // extract unsigned < condition from arg0
+               {name: "SETBE", reg: readflags, asm: "SETLS"}, // extract unsigned <= condition from arg0
+               {name: "SETA", reg: readflags, asm: "SETHI"},  // extract unsigned > condition from arg0
+               {name: "SETAE", reg: readflags, asm: "SETCC"}, // extract unsigned >= condition from arg0
 
                {name: "MOVBQSX", reg: gp11, asm: "MOVBQSX"}, // sign extend arg0 from int8 to int64
                {name: "MOVBQZX", reg: gp11, asm: "MOVBQZX"}, // zero extend arg0 from int8 to int64

diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 17d4edb221bf5746272ab93b6275c86f38c40ce6..a2e087246d17b41c73806bec38b26a86da384e8b 100644 (file)
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -2202,7 +2202,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2215,7 +2214,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2228,7 +2226,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2241,7 +2238,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2254,7 +2250,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2267,7 +2262,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2280,7 +2274,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2293,7 +2286,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2306,7 +2298,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },
@@ -2319,7 +2310,6 @@ var opcodeTable = [...]opInfo{
                        inputs: []inputInfo{
                                {0, 8589934592}, // .FLAGS
                        },
-                       clobbers: 8589934592, // .FLAGS
                        outputs: []regMask{
                                65519, // .AX .CX .DX .BX .BP .SI .DI .R8 .R9 .R10 .R11 .R12 .R13 .R14 .R15
                        },