target-alpha: Fix integer overflow checking insns

We need to write the result to the destination register before
raising any exception.  Thus inline the code for each insn, and
check for any exception after we're done.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Richard Henderson <rth@twiddle.net>

3 files changed, 56 insertions, 70 deletions

diff --git a/target-alpha/helper.h b/target-alpha/helper.h
index 9e7b771..5b1a5d9 100644
--- a/target-alpha/helper.h
+++ b/target-alpha/helper.h
@@ -1,12 +1,7 @@
 DEF_HELPER_3(excp, noreturn, env, int, int)
 DEF_HELPER_FLAGS_1(load_pcc, TCG_CALL_NO_RWG_SE, i64, env)
 
-DEF_HELPER_FLAGS_3(addqv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(addlv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(subqv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(sublv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(mullv, TCG_CALL_NO_WG, i64, env, i64, i64)
-DEF_HELPER_FLAGS_3(mulqv, TCG_CALL_NO_WG, i64, env, i64, i64)
+DEF_HELPER_FLAGS_3(check_overflow, TCG_CALL_NO_WG, void, env, i64, i64)
 
 DEF_HELPER_FLAGS_1(ctpop, TCG_CALL_NO_RWG_SE, i64, i64)
 DEF_HELPER_FLAGS_1(ctlz, TCG_CALL_NO_RWG_SE, i64, i64)
diff --git a/target-alpha/int_helper.c b/target-alpha/int_helper.c
index 7a205eb..8e4537f 100644
--- a/target-alpha/int_helper.c
+++ b/target-alpha/int_helper.c
@@ -249,64 +249,9 @@ uint64_t helper_unpkbw(uint64_t op1)
             | ((op1 & 0xff000000) << 24));
 }
 
-uint64_t helper_addqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
+void helper_check_overflow(CPUAlphaState *env, uint64_t op1, uint64_t op2)
 {
-    uint64_t tmp = op1;
-    op1 += op2;
-    if (unlikely((tmp ^ op2 ^ (-1ULL)) & (tmp ^ op1) & (1ULL << 63))) {
+    if (unlikely(op1 != op2)) {
         arith_excp(env, GETPC(), EXC_M_IOV, 0);
     }
-    return op1;
-}
-
-uint64_t helper_addlv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t tmp = op1;
-    op1 = (uint32_t)(op1 + op2);
-    if (unlikely((tmp ^ op2 ^ (-1UL)) & (tmp ^ op1) & (1UL << 31))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return op1;
-}
-
-uint64_t helper_subqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t res;
-    res = op1 - op2;
-    if (unlikely((op1 ^ op2) & (res ^ op1) & (1ULL << 63))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return res;
-}
-
-uint64_t helper_sublv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint32_t res;
-    res = op1 - op2;
-    if (unlikely((op1 ^ op2) & (res ^ op1) & (1UL << 31))) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return res;
-}
-
-uint64_t helper_mullv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    int64_t res = (int64_t)op1 * (int64_t)op2;
-
-    if (unlikely((int32_t)res != res)) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return (int64_t)((int32_t)res);
-}
-
-uint64_t helper_mulqv(CPUAlphaState *env, uint64_t op1, uint64_t op2)
-{
-    uint64_t tl, th;
-
-    muls64(&tl, &th, op1, op2);
-    /* If th != 0 && th != -1, then we had an overflow */
-    if (unlikely((th + 1) > 1)) {
-        arith_excp(env, GETPC(), EXC_M_IOV, 0);
-    }
-    return tl;
 }
diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 7868cc4..74f5d07 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -1362,7 +1362,7 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
     uint16_t fn11;
     uint8_t opc, ra, rb, rc, fpfn, fn7, lit;
     bool islit;
-    TCGv va, vb, vc, tmp;
+    TCGv va, vb, vc, tmp, tmp2;
     TCGv_i32 t32;
     ExitStatus ret;
 
@@ -1574,11 +1574,23 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x40:
             /* ADDL/V */
-            gen_helper_addlv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_add_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x49:
             /* SUBL/V */
-            gen_helper_sublv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_sub_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x4D:
             /* CMPLT */
@@ -1586,11 +1598,33 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x60:
             /* ADDQ/V */
-            gen_helper_addqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_eqv_i64(tmp, va, vb);
+            tcg_gen_mov_i64(tmp2, va);
+            tcg_gen_add_i64(vc, va, vb);
+            tcg_gen_xor_i64(tmp2, tmp2, vc);
+            tcg_gen_and_i64(tmp, tmp, tmp2);
+            tcg_gen_shri_i64(tmp, tmp, 63);
+            tcg_gen_movi_i64(tmp2, 0);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         case 0x69:
             /* SUBQ/V */
-            gen_helper_subqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_xor_i64(tmp, va, vb);
+            tcg_gen_mov_i64(tmp2, va);
+            tcg_gen_sub_i64(vc, va, vb);
+            tcg_gen_xor_i64(tmp2, tmp2, vc);
+            tcg_gen_and_i64(tmp, tmp, tmp2);
+            tcg_gen_shri_i64(tmp, tmp, 63);
+            tcg_gen_movi_i64(tmp2, 0);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         case 0x6D:
             /* CMPLE */
@@ -1885,11 +1919,23 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn)
             break;
         case 0x40:
             /* MULL/V */
-            gen_helper_mullv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tcg_gen_ext32s_i64(tmp, va);
+            tcg_gen_ext32s_i64(vc, vb);
+            tcg_gen_mul_i64(tmp, tmp, vc);
+            tcg_gen_ext32s_i64(vc, tmp);
+            gen_helper_check_overflow(cpu_env, vc, tmp);
+            tcg_temp_free(tmp);
             break;
         case 0x60:
             /* MULQ/V */
-            gen_helper_mulqv(vc, cpu_env, va, vb);
+            tmp = tcg_temp_new();
+            tmp2 = tcg_temp_new();
+            tcg_gen_muls2_i64(vc, tmp, va, vb);
+            tcg_gen_sari_i64(tmp2, vc, 63);
+            gen_helper_check_overflow(cpu_env, tmp, tmp2);
+            tcg_temp_free(tmp);
+            tcg_temp_free(tmp2);
             break;
         default:
             goto invalid_opc;