target-arm: A64: Fix shifts into sign bit

Fix attempts to shift into the sign bit of an int, which is undefined
behaviour in C and warned about by the clang sanitizer.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1423233250-15853-2-git-send-email-peter.maydell@linaro.org

target-arm/translate-a64.c

@@ -1077,7 +1077,7 @@ static void disas_uncond_b_imm(DisasContext *s, uint32_t insn)
 {
     uint64_t addr = s->pc + sextract32(insn, 0, 26) * 4 - 4;
 
-    if (insn & (1 << 31)) {
+    if (insn & (1U << 31)) {
         /* C5.6.26 BL Branch with link */
         tcg_gen_movi_i64(cpu_reg(s, 30), s->pc);
     }
@@ -1271,7 +1271,7 @@ static void gen_get_nzcv(TCGv_i64 tcg_rt)
     TCGv_i32 nzcv = tcg_temp_new_i32();
 
     /* build bit 31, N */
-    tcg_gen_andi_i32(nzcv, cpu_NF, (1 << 31));
+    tcg_gen_andi_i32(nzcv, cpu_NF, (1U << 31));
     /* build bit 30, Z */
     tcg_gen_setcondi_i32(TCG_COND_EQ, tmp, cpu_ZF, 0);
     tcg_gen_deposit_i32(nzcv, nzcv, tmp, 30, 1);
@@ -1296,7 +1296,7 @@ static void gen_set_nzcv(TCGv_i64 tcg_rt)
     tcg_gen_trunc_i64_i32(nzcv, tcg_rt);
 
     /* bit 31, N */
-    tcg_gen_andi_i32(cpu_NF, nzcv, (1 << 31));
+    tcg_gen_andi_i32(cpu_NF, nzcv, (1U << 31));
     /* bit 30, Z */
     tcg_gen_andi_i32(cpu_ZF, nzcv, (1 << 30));
     tcg_gen_setcondi_i32(TCG_COND_EQ, cpu_ZF, cpu_ZF, 0);