cmd/compile: code cleanup

Change-Id: Ibf68e663f29a5cb3b64a7d923c005c16da647769
Reviewed-on: https://go-review.googlesource.com/c/go/+/266537
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

3 files changed, 30 insertions, 26 deletions

diff --git a/src/cmd/compile/internal/amd64/ssa.go b/src/cmd/compile/internal/amd64/ssa.go
index f30a47b903..76e33a3689 100644
--- a/src/cmd/compile/internal/amd64/ssa.go
+++ b/src/cmd/compile/internal/amd64/ssa.go
@@ -42,10 +42,11 @@ func ssaMarkMoves(s *gc.SSAGenState, b *ssa.Block) {
 // loadByType returns the load instruction of the given type.
 func loadByType(t *types.Type) obj.As {
 	// Avoid partial register write
-	if !t.IsFloat() && t.Size() <= 2 {
-		if t.Size() == 1 {
+	if !t.IsFloat() {
+		switch t.Size() {
+		case 1:
 			return x86.AMOVBLZX
-		} else {
+		case 2:
 			return x86.AMOVWLZX
 		}
 	}
@@ -1070,7 +1071,7 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p := s.Prog(v.Op.Asm())
 		val := v.AuxInt
 		// 0 means math.RoundToEven, 1 Floor, 2 Ceil, 3 Trunc
-		if val != 0 && val != 1 && val != 2 && val != 3 {
+		if val < 0 || val > 3 {
 			v.Fatalf("Invalid rounding mode")
 		}
 		p.From.Offset = val
diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index 9ddc53060c..63994d1778 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -304,37 +304,39 @@ commas. For example:
 `
 	}
 
-	if phase == "check" && flag == "on" {
-		checkEnabled = val != 0
-		debugPoset = checkEnabled // also turn on advanced self-checking in prove's datastructure
-		return ""
-	}
-	if phase == "check" && flag == "off" {
-		checkEnabled = val == 0
-		debugPoset = checkEnabled
-		return ""
-	}
-	if phase == "check" && flag == "seed" {
-		checkEnabled = true
-		checkRandSeed = val
-		debugPoset = checkEnabled
-		return ""
+	if phase == "check" {
+		switch flag {
+		case "on":
+			checkEnabled = val != 0
+			debugPoset = checkEnabled // also turn on advanced self-checking in prove's datastructure
+			return ""
+		case "off":
+			checkEnabled = val == 0
+			debugPoset = checkEnabled
+			return ""
+		case "seed":
+			checkEnabled = true
+			checkRandSeed = val
+			debugPoset = checkEnabled
+			return ""
+		}
 	}
 
 	alltime := false
 	allmem := false
 	alldump := false
 	if phase == "all" {
-		if flag == "time" {
+		switch flag {
+		case "time":
 			alltime = val != 0
-		} else if flag == "mem" {
+		case "mem":
 			allmem = val != 0
-		} else if flag == "dump" {
+		case "dump":
 			alldump = val != 0
 			if alldump {
 				BuildDump = valString
 			}
-		} else {
+		default:
 			return fmt.Sprintf("Did not find a flag matching %s in -d=ssa/%s debug option", flag, phase)
 		}
 	}
diff --git a/src/cmd/compile/internal/x86/ssa.go b/src/cmd/compile/internal/x86/ssa.go
index 74a4570770..fbf76d0c5e 100644
--- a/src/cmd/compile/internal/x86/ssa.go
+++ b/src/cmd/compile/internal/x86/ssa.go
@@ -42,10 +42,11 @@ func ssaMarkMoves(s *gc.SSAGenState, b *ssa.Block) {
 // loadByType returns the load instruction of the given type.
 func loadByType(t *types.Type) obj.As {
 	// Avoid partial register write
-	if !t.IsFloat() && t.Size() <= 2 {
-		if t.Size() == 1 {
+	if !t.IsFloat() {
+		switch t.Size() {
+		case 1:
 			return x86.AMOVBLZX
-		} else {
+		case 2:
 			return x86.AMOVWLZX
 		}
 	}