fix compare_and_branch

Author: y1yang0

test/codegen/compare_and_branch.go

@@ -35,12 +35,12 @@ func si64x8() {
 	}
 
 	// s390x:"CGIJ\t[$]2, R[0-9]+, [$]127, "
-	for i := int64(0); i >= 128; i++ {
+	for i := int64(129); i >= 128; i-- {
 		dummy()
 	}
 
 	// s390x:"CGIJ\t[$]4, R[0-9]+, [$]-128, "
-	for i := int64(0); i <= -129; i-- {
+	for i := int64(-130); i <= -129; i++ {
 		dummy()
 	}
 }
@@ -71,7 +71,7 @@ func ui64x8() {
 	}
 
 	// s390x:"CLGIJ\t[$]2, R[0-9]+, [$]255, "
-	for i := uint64(0); i >= 256; i-- {
+	for i := uint64(257); i >= 256; i-- {
 		dummy()
 	}
 
@@ -107,12 +107,12 @@ func si32x8() {
 	}
 
 	// s390x:"CIJ\t[$]2, R[0-9]+, [$]127, "
-	for i := int32(0); i >= 128; i++ {
+	for i := int32(129); i >= 128; i-- {
 		dummy()
 	}
 
 	// s390x:"CIJ\t[$]4, R[0-9]+, [$]-128, "
-	for i := int32(0); i <= -129; i-- {
+	for i := int32(-130); i <= -129; i++ {
 		dummy()
 	}
 }
@@ -143,7 +143,7 @@ func ui32x8() {
 	}
 
 	// s390x:"CLIJ\t[$]2, R[0-9]+, [$]255, "
-	for i := uint32(0); i >= 256; i-- {
+	for i := uint32(257); i >= 256; i-- {
 		dummy()
 	}