diff --git a/arch/AArch64/AArch64Disassembler.c b/arch/AArch64/AArch64Disassembler.c
index 600d402b..41dd4881 100644
--- a/arch/AArch64/AArch64Disassembler.c
+++ b/arch/AArch64/AArch64Disassembler.c
@@ -224,7 +224,6 @@ static DecodeStatus _getInstruction(cs_struct *ud, MCInst *MI,
 {
 	uint32_t insn;
 	DecodeStatus result;
-	int i;
 
 	if (code_len < 4) {
 		// not enough data
@@ -234,7 +233,7 @@ static DecodeStatus _getInstruction(cs_struct *ud, MCInst *MI,
 
 	if (MI->flat_insn->detail) {
 		memset(MI->flat_insn->detail, 0, sizeof(cs_detail));
-		for (i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm64.operands); i++)
+		for (size_t i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm64.operands); i++)
 			MI->flat_insn->detail->arm64.operands[i].vector_index = -1;
 	}
 
diff --git a/arch/ARM/ARMDisassembler.c b/arch/ARM/ARMDisassembler.c
index 9846e59a..f4c6d7a2 100644
--- a/arch/ARM/ARMDisassembler.c
+++ b/arch/ARM/ARMDisassembler.c
@@ -687,7 +687,6 @@ static DecodeStatus _Thumb_getInstruction(cs_struct *ud, MCInst *MI, const uint8
 	bool InITBlock;
 	unsigned Firstcond, Mask; 
 	uint32_t NEONLdStInsn, insn32, NEONDataInsn, NEONCryptoInsn, NEONv8Insn;
-	int i;
 
 	// We want to read exactly 2 bytes of data.
 	if (code_len < 2)
@@ -698,7 +697,7 @@ static DecodeStatus _Thumb_getInstruction(cs_struct *ud, MCInst *MI, const uint8
 
 	if (MI->flat_insn->detail) {
 		memset(&MI->flat_insn->detail->arm, 0, sizeof(cs_arm));
-		for (i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm.operands); i++)
+		for (size_t i = 0; i < ARR_SIZE(MI->flat_insn->detail->arm.operands); i++)
 			MI->flat_insn->detail->arm.operands[i].vector_index = -1;
 	}
 
diff --git a/arch/PowerPC/PPCMapping.c b/arch/PowerPC/PPCMapping.c
index ef354ee7..ee2d4b45 100644
--- a/arch/PowerPC/PPCMapping.c
+++ b/arch/PowerPC/PPCMapping.c
@@ -8089,9 +8089,7 @@ static struct ppc_alias alias_insn_name_maps[] = {
 // given alias mnemonic, return instruction ID & CC
 bool PPC_alias_insn(const char *name, struct ppc_alias *alias)
 {
-	int i;
-
-	for(i = 0; i < ARR_SIZE(alias_insn_name_maps); i++) {
+	for(size_t i = 0; i < ARR_SIZE(alias_insn_name_maps); i++) {
 		if (!strcmp(name, alias_insn_name_maps[i].mnem)) {
 			alias->id = alias_insn_name_maps[i].id;
 			alias->cc = alias_insn_name_maps[i].cc;
@@ -8100,7 +8098,7 @@ bool PPC_alias_insn(const char *name, struct ppc_alias *alias)
 	}
 
 	// not really an alias insn
-	i = name2id(&insn_name_maps[1], ARR_SIZE(insn_name_maps) - 1, name);
+	int i = name2id(&insn_name_maps[1], ARR_SIZE(insn_name_maps) - 1, name);
 	if (i != -1) {
 		alias->id = insn_name_maps[i].id;
 		alias->cc = PPC_BC_INVALID;