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cmd/asm, cmd/internal/obj/riscv: fix branch pseudo-instructions
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Pseudo branch instructions BGT, BGTU, BLE, and BLEU implemented In
CL 226397 were translated inconsistently compared to other ones due
to the inversion of registers. For instance, while "BLT a, b" generates
"jump if a < b", "BLE a, b" generates "jump if b <= a."

This CL fixes the translation in the assembler and the tests.

Change-Id: Ia757be73e848734ca5b3a790e081f7c4f98c30f2
Reviewed-on: https://go-review.googlesource.com/c/go/+/271911
Reviewed-by: Cherry Zhang <[email protected]>
Reviewed-by: Joel Sing <[email protected]>
Run-TryBot: Joel Sing <[email protected]>
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@NonerKao @4a6f656c
NonerKao authored and 4a6f656c committed Dec 2, 2020
1 parent 73e796c commit 0433845
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Showing 3 changed files with 31 additions and 34 deletions.
8 changes: 4 additions & 4 deletions src/cmd/asm/internal/asm/testdata/riscvenc.s
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Original file line number Diff line number Diff line change
Expand Up @@ -340,11 +340,11 @@ start:
// Branch pseudo-instructions
BEQZ X5, start // BEQZ X5, 2 // e38602c0
BGEZ X5, start // BGEZ X5, 2 // e3d402c0
BGT X5, X6, start // BGT X5, X6, 2 // e3c262c0
BGTU X5, X6, start // BGTU X5, X6, 2 // e3e062c0
BGT X5, X6, start // BGT X5, X6, 2 // e34253c0
BGTU X5, X6, start // BGTU X5, X6, 2 // e36053c0
BGTZ X5, start // BGTZ X5, 2 // e34e50be
BLE X5, X6, start // BLE X5, X6, 2 // e3dc62be
BLEU X5, X6, start // BLEU X5, X6, 2 // e3fa62be
BLE X5, X6, start // BLE X5, X6, 2 // e35c53be
BLEU X5, X6, start // BLEU X5, X6, 2 // e37a53be
BLEZ X5, start // BLEZ X5, 2 // e35850be
BLTZ X5, start // BLTZ X5, 2 // e3c602be
BNEZ X5, start // BNEZ X5, 2 // e39402be
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8 changes: 4 additions & 4 deletions src/cmd/internal/obj/riscv/obj.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1777,15 +1777,15 @@ func instructionsForProg(p *obj.Prog) []*instruction {
case ABGEZ:
ins.as, ins.rs1, ins.rs2 = ABGE, REG_ZERO, uint32(p.From.Reg)
case ABGT:
ins.as, ins.rs1, ins.rs2 = ABLT, uint32(p.Reg), uint32(p.From.Reg)
ins.as, ins.rs1, ins.rs2 = ABLT, uint32(p.From.Reg), uint32(p.Reg)
case ABGTU:
ins.as, ins.rs1, ins.rs2 = ABLTU, uint32(p.Reg), uint32(p.From.Reg)
ins.as, ins.rs1, ins.rs2 = ABLTU, uint32(p.From.Reg), uint32(p.Reg)
case ABGTZ:
ins.as, ins.rs1, ins.rs2 = ABLT, uint32(p.From.Reg), REG_ZERO
case ABLE:
ins.as, ins.rs1, ins.rs2 = ABGE, uint32(p.Reg), uint32(p.From.Reg)
ins.as, ins.rs1, ins.rs2 = ABGE, uint32(p.From.Reg), uint32(p.Reg)
case ABLEU:
ins.as, ins.rs1, ins.rs2 = ABGEU, uint32(p.Reg), uint32(p.From.Reg)
ins.as, ins.rs1, ins.rs2 = ABGEU, uint32(p.From.Reg), uint32(p.Reg)
case ABLEZ:
ins.as, ins.rs1, ins.rs2 = ABGE, uint32(p.From.Reg), REG_ZERO
case ABLTZ:
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49 changes: 23 additions & 26 deletions src/cmd/internal/obj/riscv/testdata/testbranch/branch_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -43,33 +43,34 @@ func TestBranchCondition(t *testing.T) {
{"BGEU", 0, -1, testBGEU, false},
{"BGEU", -1, 0, testBGEU, true},
{"BGEU", 1, 0, testBGEU, true},
{"BGT", 0, 1, testBGT, true},
{"BGT", 0, 1, testBGT, false},
{"BGT", 0, 0, testBGT, false},
{"BGT", 0, -1, testBGT, false},
{"BGT", -1, 0, testBGT, true},
{"BGT", 1, 0, testBGT, false},
{"BGTU", 0, 1, testBGTU, true},
{"BGTU", 0, -1, testBGTU, true},
{"BGTU", -1, 0, testBGTU, false},
{"BGTU", 1, 0, testBGTU, false},
{"BLE", 0, 1, testBLE, false},
{"BLE", 0, -1, testBLE, true},
{"BGT", 0, -1, testBGT, true},
{"BGT", -1, 0, testBGT, false},
{"BGT", 1, 0, testBGT, true},
{"BGTU", 0, 1, testBGTU, false},
{"BGTU", 0, 0, testBGTU, false},
{"BGTU", 0, -1, testBGTU, false},
{"BGTU", -1, 0, testBGTU, true},
{"BGTU", 1, 0, testBGTU, true},
{"BLE", 0, 1, testBLE, true},
{"BLE", 0, 0, testBLE, true},
{"BLE", -1, 0, testBLE, false},
{"BLE", 1, 0, testBLE, true},
{"BLEU", 0, 1, testBLEU, false},
{"BLEU", 0, -1, testBLEU, false},
{"BLE", 0, -1, testBLE, false},
{"BLE", -1, 0, testBLE, true},
{"BLE", 1, 0, testBLE, false},
{"BLEU", 0, 1, testBLEU, true},
{"BLEU", 0, 0, testBLEU, true},
{"BLEU", -1, 0, testBLEU, true},
{"BLEU", 1, 0, testBLEU, true},
{"BLEU", 0, -1, testBLEU, true},
{"BLEU", -1, 0, testBLEU, false},
{"BLEU", 1, 0, testBLEU, false},
{"BLT", 0, 1, testBLT, true},
{"BLT", 0, -1, testBLT, false},
{"BLT", 0, 0, testBLT, false},
{"BLT", 0, -1, testBLT, false},
{"BLT", -1, 0, testBLT, true},
{"BLT", 1, 0, testBLT, false},
{"BLTU", 0, 1, testBLTU, true},
{"BLTU", 0, -1, testBLTU, true},
{"BLTU", 0, 0, testBLTU, false},
{"BLTU", 0, -1, testBLTU, true},
{"BLTU", -1, 0, testBLTU, false},
{"BLTU", 1, 0, testBLTU, false},
}
Expand All @@ -82,17 +83,13 @@ func TestBranchCondition(t *testing.T) {
case "BGEU":
fn = func(a, b int64) bool { return uint64(a) >= uint64(b) }
case "BGT":
// TODO: Currently reversed.
fn = func(a, b int64) bool { return b > a }
fn = func(a, b int64) bool { return a > b }
case "BGTU":
// TODO: Currently reversed.
fn = func(a, b int64) bool { return uint64(b) > uint64(a) }
fn = func(a, b int64) bool { return uint64(a) > uint64(b) }
case "BLE":
// TODO: Currently reversed.
fn = func(a, b int64) bool { return b <= a }
fn = func(a, b int64) bool { return a <= b }
case "BLEU":
// TODO: Currently reversed.
fn = func(a, b int64) bool { return uint64(b) <= uint64(a) }
fn = func(a, b int64) bool { return uint64(a) <= uint64(b) }
case "BLT":
fn = func(a, b int64) bool { return a < b }
case "BLTU":
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