Clean up IR construction for insns that do not have straight-line

internal control flow. Introduce a few new convenience functions: iterate,
iterate_if, next_insn_if that are now used to build IR for insns with implicit
loops. These functions behave like if_condition_goto, except they do
not terminate the super block and do not call put_IA(next insn). Previously,
the guest_IA was assigned possibly several times for such insn. Now we do
it exactly once as it should be. This improves complaints for cu21 which was
the motivation behind this patch.
As a side effect insns with an implicit loop no longer terminate the super
block. All calls to dummy_put_IA have been eliminated.
No changes in runtime performance were observed.

git-svn-id: svn://svn.valgrind.org/vex/trunk@2449

diff --git a/VEX/priv/guest_s390_toIR.c b/VEX/priv/guest_s390_toIR.c
index 94b5a630c289f3b4dfd3ccf98be5dc27699e772e..a4a0562d90430e4ca3aff6730ae929d04d99e3c7 100644 (file)
--- a/VEX/priv/guest_s390_toIR.c
+++ b/VEX/priv/guest_s390_toIR.c
@@ -143,15 +143,6 @@ put_IA(IRExpr *address)
    stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_IA), address));
 }
 
-/* Add a dummy put to the guest_IA to satisfy an assert in bb_to_IR
-   that wants the last statement in an IRSB to be a put to the guest_IA.
-   Mostly used for insns that use the "counter" pseudo guest reg. */
-static __inline__ void
-dummy_put_IA(void)
-{
-   put_IA(IRExpr_Get(S390X_GUEST_OFFSET(guest_IA), Ity_I64));
-}
-
 /* Create a temporary of the given type and assign the expression to it */
 static __inline__ IRTemp
 mktemp(IRType type, IRExpr *expr)
@@ -386,6 +377,54 @@ system_call(IRExpr *sysno)
    dis_res->jk_StopHere = Ijk_Sys_syscall;
 }
 
+/* A side exit that branches back to the current insn if CONDITION is
+   true. Does not set DisResult. */
+static void
+iterate_if(IRExpr *condition)
+{
+   vassert(typeOfIRExpr(irsb->tyenv, condition) == Ity_I1);
+
+   stmt(IRStmt_Exit(condition, Ijk_Boring, IRConst_U64(guest_IA_curr_instr),
+                    S390X_GUEST_OFFSET(guest_IA)));
+}
+
+/* A side exit that branches back to the current insn.
+   Does not set DisResult. */
+static __inline__ void
+iterate(void)
+{
+   iterate_if(IRExpr_Const(IRConst_U1(True)));
+}
+
+/* A side exit that branches back to the insn immediately following the
+   current insn if CONDITION is true. Does not set DisResult. */
+static void
+next_insn_if(IRExpr *condition)
+{
+   vassert(typeOfIRExpr(irsb->tyenv, condition) == Ity_I1);
+
+   stmt(IRStmt_Exit(condition, Ijk_Boring, IRConst_U64(guest_IA_next_instr),
+                    S390X_GUEST_OFFSET(guest_IA)));
+}
+
+/* Convenience function to restart the current insn */
+static void
+restart_if(IRExpr *condition)
+{
+   vassert(typeOfIRExpr(irsb->tyenv, condition) == Ity_I1);
+
+   stmt(IRStmt_Exit(condition, Ijk_TInval, IRConst_U64(guest_IA_curr_instr),
+                    S390X_GUEST_OFFSET(guest_IA)));
+}
+
+/* Convenience function to yield to thread scheduler */
+static void
+yield_if(IRExpr *condition)
+{
+   stmt(IRStmt_Exit(condition, Ijk_Yield, IRConst_U64(guest_IA_next_instr),
+                    S390X_GUEST_OFFSET(guest_IA)));
+}
+
 /* Encode the s390 rounding mode as it appears in the m3/m4 fields of certain
    instructions to VEX's IRRoundingMode. */
 static IRRoundingMode
@@ -1832,14 +1871,15 @@ s390_format_RSY_RDRM(HChar *(*irgen)(UChar r1, IRTemp op2addr),
    IRTemp op2addr = newTemp(Ity_I64);
    IRTemp d2 = newTemp(Ity_I64);
 
-   if_condition_goto(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)));
+
    assign(d2, mkU64(((ULong)(Long)(Char)dh2 << 12) | ((ULong)dl2)));
    assign(op2addr, binop(Iop_Add64, mkexpr(d2), b2 != 0 ? get_gpr_dw0(b2) :
           mkU64(0)));
 
    irgen(r1, op2addr);
-   dummy_put_IA();
+
+   vassert(dis_res->whatNext == Dis_Continue);
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_FE))
       s390_disasm(ENC3(XMNM, GPR, SDXB), xmnm_kind, m3, r1, dh2, dl2, 0, b2);
@@ -5814,10 +5854,8 @@ s390_irgen_LNGFR(UChar r1, UChar r2 __attribute__((unused)))
 static HChar *
 s390_irgen_LOCR(UChar m3, UChar r1, UChar r2)
 {
-   if_condition_goto(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)));
    put_gpr_w1(r1, get_gpr_w1(r2));
-   dummy_put_IA();
 
    return "locr";
 }
@@ -5825,10 +5863,8 @@ s390_irgen_LOCR(UChar m3, UChar r1, UChar r2)
 static HChar *
 s390_irgen_LOCGR(UChar m3, UChar r1, UChar r2)
 {
-   if_condition_goto(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32, s390_call_calculate_cond(m3), mkU32(0)));
    put_gpr_dw0(r1, get_gpr_dw0(r2));
-   dummy_put_IA();
 
    return "locgr";
 }
@@ -8535,7 +8571,6 @@ s390_irgen_CLC(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU64(length));
    s390_irgen_CLC_EX(len, start1, start2);
-   dummy_put_IA();
 
    return "clc";
 }
@@ -8565,9 +8600,8 @@ s390_irgen_CLCL(UChar r1, UChar r2)
 
    /* len1 == 0 and len2 == 0? Exit */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ32, binop(Iop_Or32, mkexpr(len1),
-                                              mkexpr(len2)), mkU32(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32, binop(Iop_Or32, mkexpr(len1),
+                                         mkexpr(len2)), mkU32(0)));
 
    /* Because mkite evaluates both the then-clause and the else-clause
       we cannot load directly from addr1 here. If len1 is 0, then adddr1
@@ -8590,8 +8624,7 @@ s390_irgen_CLCL(UChar r1, UChar r2)
 
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, single1, single2, False);
    /* Fields differ ? */
-   if_condition_goto(binop(Iop_CmpNE8, mkexpr(single1), mkexpr(single2)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpNE8, mkexpr(single1), mkexpr(single2)));
 
    /* Update len1 and addr1, unless len1 == 0. */
    put_gpr_dw0(r1,
@@ -8617,7 +8650,7 @@ s390_irgen_CLCL(UChar r1, UChar r2)
                     binop(Iop_And32, mkexpr(r2p1), mkU32(0xFF000000u)),
                     binop(Iop_Sub32, mkexpr(r2p1), mkU32(1))));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "clcl";
 }
@@ -8643,9 +8676,8 @@ s390_irgen_CLCLE(UChar r1, UChar r3, IRTemp pad2)
 
    /* len1 == 0 and len3 == 0? Exit */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64,binop(Iop_Or64, mkexpr(len1),
-                                             mkexpr(len3)), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64,binop(Iop_Or64, mkexpr(len1),
+                                        mkexpr(len3)), mkU64(0)));
 
    /* A mux requires both ways to be possible. This is a way to prevent clcle
       from reading from addr1 if it should read from the pad. Since the pad
@@ -8671,8 +8703,7 @@ s390_irgen_CLCLE(UChar r1, UChar r3, IRTemp pad2)
 
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, single1, single3, False);
    /* Both fields differ ? */
-   if_condition_goto(binop(Iop_CmpNE8, mkexpr(single1), mkexpr(single3)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpNE8, mkexpr(single1), mkexpr(single3)));
 
    /* If a length in 0 we must not change this length and the address */
    put_gpr_dw0(r1,
@@ -8693,7 +8724,7 @@ s390_irgen_CLCLE(UChar r1, UChar r3, IRTemp pad2)
                mkite(binop(Iop_CmpEQ64, mkexpr(len3), mkU64(0)),
                      mkU64(0), binop(Iop_Sub64, mkexpr(len3), mkU64(1))));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "clcle";
 }
@@ -8738,13 +8769,11 @@ s390_irgen_CLC_EX(IRTemp length, IRTemp start1, IRTemp start2)
                       False);
 
    /* Both fields differ ? */
-   if_condition_goto(binop(Iop_CmpNE8, mkexpr(current1), mkexpr(current2)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpNE8, mkexpr(current1), mkexpr(current2)));
 
    /* Check for end of field */
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
-   if_condition_goto(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)));
    put_counter_dw0(mkU64(0));
 }
 
@@ -8760,8 +8789,7 @@ s390_irgen_MVC_EX(IRTemp length, IRTemp start1, IRTemp start2)
 
    /* Check for end of field */
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
-   if_condition_goto(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)));
    put_counter_dw0(mkU64(0));
 }
 
@@ -8783,15 +8811,15 @@ s390_irgen_TR_EX(IRTemp length, IRTemp start1, IRTemp start2)
    store(binop(Iop_Add64, mkexpr(start1), mkexpr(counter)), mkexpr(op1));
 
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
-   if_condition_goto(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE64, mkexpr(counter), mkexpr(length)));
    put_counter_dw0(mkU64(0));
 }
 
 
 static void
 s390_irgen_EX_SS(UChar r, IRTemp addr2,
-void (*irgen)(IRTemp length, IRTemp start1, IRTemp start2), int lensize)
+                 void (*irgen)(IRTemp length, IRTemp start1, IRTemp start2),
+                 int lensize)
 {
    struct SS {
       unsigned int op :  8;
@@ -8828,8 +8856,7 @@ void (*irgen)(IRTemp length, IRTemp start1, IRTemp start2), int lensize)
    stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TISTART),
                    mkU64(guest_IA_curr_instr)));
    stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TILEN), mkU64(4)));
-   stmt(IRStmt_Exit(mkexpr(cond), Ijk_TInval, IRConst_U64(guest_IA_curr_instr),
-                    S390X_GUEST_OFFSET(guest_IA)));
+   restart_if(mkexpr(cond));
 
    ss.bytes = last_execute_target;
    assign(start1, binop(Iop_Add64, mkU64(ss.dec.d1),
@@ -8839,7 +8866,6 @@ void (*irgen)(IRTemp length, IRTemp start1, IRTemp start2), int lensize)
    assign(len, unop(lensize == 64 ? Iop_8Uto64 : Iop_8Uto32, binop(Iop_Or8,
           r != 0 ? get_gpr_b7(r): mkU8(0), mkU8(ss.dec.l))));
    irgen(len, start1, start2);
-   dummy_put_IA();
 
    last_execute_target = 0;
 }
@@ -8861,9 +8887,8 @@ s390_irgen_EX(UChar r1, IRTemp addr2)
       stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TISTART),
                       mkU64(guest_IA_curr_instr)));
       stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TILEN), mkU64(4)));
-      stmt(IRStmt_Exit(IRExpr_Const(IRConst_U1(True)), Ijk_TInval,
-                       IRConst_U64(guest_IA_curr_instr),
-                       S390X_GUEST_OFFSET(guest_IA)));
+      restart_if(IRExpr_Const(IRConst_U1(True)));
+
       /* we know that this will be invalidated */
       put_IA(mkaddr_expr(guest_IA_next_instr));
       dis_res->whatNext = Dis_StopHere;
@@ -8935,9 +8960,7 @@ s390_irgen_EX(UChar r1, IRTemp addr2)
       /* and restart */
       stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TISTART), mkU64(guest_IA_curr_instr)));
       stmt(IRStmt_Put(S390X_GUEST_OFFSET(guest_TILEN), mkU64(4)));
-      stmt(IRStmt_Exit(mkexpr(cond), Ijk_TInval,
-                       IRConst_U64(guest_IA_curr_instr),
-                       S390X_GUEST_OFFSET(guest_IA)));
+      restart_if(mkexpr(cond));
 
       /* Now comes the actual translation */
       bytes = (UChar *) &last_execute_target;
@@ -8947,7 +8970,6 @@ s390_irgen_EX(UChar r1, IRTemp addr2)
          vex_printf("    which was executed by\n");
       /* dont make useless translations in the next execute */
       last_execute_target = 0;
-      dummy_put_IA();
    }
    }
    return "ex";
@@ -8995,8 +9017,7 @@ s390_irgen_SRST(UChar r1, UChar r2)
    // start = next?  CC=2 and out r1 and r2 unchanged
    s390_cc_set(2);
    put_gpr_dw0(r2, binop(Iop_Sub64, mkexpr(address), mkexpr(counter)));
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(address), mkexpr(next)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(address), mkexpr(next)));
 
    assign(byte, load(Ity_I8, mkexpr(address)));
    assign(delim, get_gpr_b7(0));
@@ -9004,15 +9025,14 @@ s390_irgen_SRST(UChar r1, UChar r2)
    // byte = delim? CC=1, R1=address
    s390_cc_set(1);
    put_gpr_dw0(r1,  mkexpr(address));
-   if_condition_goto(binop(Iop_CmpEQ8, mkexpr(delim), mkexpr(byte)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ8, mkexpr(delim), mkexpr(byte)));
 
    // else: all equal, no end yet, loop
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
    put_gpr_dw0(r1, mkexpr(next));
    put_gpr_dw0(r2, binop(Iop_Add64, mkexpr(address), mkU64(1)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "srst";
 }
@@ -9039,43 +9059,38 @@ s390_irgen_CLST(UChar r1, UChar r2)
    s390_cc_set(0);
    put_gpr_dw0(r1, binop(Iop_Sub64, mkexpr(address1), mkexpr(counter)));
    put_gpr_dw0(r2, binop(Iop_Sub64, mkexpr(address2), mkexpr(counter)));
-   if_condition_goto(binop(Iop_CmpEQ8, mkU8(0),
-                           binop(Iop_Or8,
-                                 binop(Iop_Xor8, mkexpr(byte1), mkexpr(end)),
-                                 binop(Iop_Xor8, mkexpr(byte2), mkexpr(end)))),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ8, mkU8(0),
+                      binop(Iop_Or8,
+                            binop(Iop_Xor8, mkexpr(byte1), mkexpr(end)),
+                            binop(Iop_Xor8, mkexpr(byte2), mkexpr(end)))));
 
    put_gpr_dw0(r1, mkexpr(address1));
    put_gpr_dw0(r2, mkexpr(address2));
 
    // End found in string1
    s390_cc_set(1);
-   if_condition_goto(binop(Iop_CmpEQ8, mkexpr(end), mkexpr(byte1)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ8, mkexpr(end), mkexpr(byte1)));
 
    // End found in string2
    s390_cc_set(2);
-   if_condition_goto(binop(Iop_CmpEQ8, mkexpr(end), mkexpr(byte2)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ8, mkexpr(end), mkexpr(byte2)));
 
    // string1 < string2
    s390_cc_set(1);
-   if_condition_goto(binop(Iop_CmpLT32U, unop(Iop_8Uto32, mkexpr(byte1)),
-                           unop(Iop_8Uto32, mkexpr(byte2))),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT32U, unop(Iop_8Uto32, mkexpr(byte1)),
+                      unop(Iop_8Uto32, mkexpr(byte2))));
 
    // string2 < string1
    s390_cc_set(2);
-   if_condition_goto(binop(Iop_CmpLT32U, unop(Iop_8Uto32, mkexpr(byte2)),
-                           unop(Iop_8Uto32, mkexpr(byte1))),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT32U, unop(Iop_8Uto32, mkexpr(byte2)),
+                      unop(Iop_8Uto32, mkexpr(byte1))));
 
    // else: all equal, no end yet, loop
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
    put_gpr_dw0(r1, binop(Iop_Add64, get_gpr_dw0(r1), mkU64(1)));
    put_gpr_dw0(r2, binop(Iop_Add64, get_gpr_dw0(r2), mkU64(1)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "clst";
 }
@@ -9265,8 +9280,7 @@ s390_irgen_xonc(IROp op, IRTemp length, IRTemp start1, IRTemp start2)
 
    /* Check for end of field */
    put_counter_w0(binop(Iop_Add32, mkexpr(counter), mkU32(1)));
-   if_condition_goto(binop(Iop_CmpNE32, mkexpr(counter), mkexpr(length)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE32, mkexpr(counter), mkexpr(length)));
    s390_cc_thunk_put1(S390_CC_OP_BITWISE, mktemp(Ity_I32, get_counter_w1()),
                       False);
    put_counter_dw0(mkU64(0));
@@ -9279,7 +9293,6 @@ s390_irgen_XC(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU32(length));
    s390_irgen_xonc(Iop_Xor8, len, start1, start2);
-   dummy_put_IA();
 
    return "xc";
 }
@@ -9310,15 +9323,13 @@ s390_irgen_XC_sameloc(UChar length, UChar b, UShort d)
 
      /* Check for end of field */
      put_counter_w0(binop(Iop_Add32, mkexpr(counter), mkU32(1)));
-     if_condition_goto(binop(Iop_CmpNE32, mkexpr(counter), mkU32(length)),
-                       guest_IA_curr_instr);
+     iterate_if(binop(Iop_CmpNE32, mkexpr(counter), mkU32(length)));
 
      /* Reset counter */
      put_counter_dw0(mkU64(0));
    }
 
    s390_cc_thunk_put1(S390_CC_OP_BITWISE, mktemp(Ity_I32, mkU32(0)), False);
-   dummy_put_IA();
 
    if (UNLIKELY(vex_traceflags & VEX_TRACE_FE))
       s390_disasm(ENC3(MNM, UDLB, UDXB), "xc", d, length, b, d, 0, b);
@@ -9331,7 +9342,6 @@ s390_irgen_NC(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU32(length));
    s390_irgen_xonc(Iop_And8, len, start1, start2);
-   dummy_put_IA();
 
    return "nc";
 }
@@ -9343,7 +9353,6 @@ s390_irgen_OC(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU32(length));
    s390_irgen_xonc(Iop_Or8, len, start1, start2);
-   dummy_put_IA();
 
    return "oc";
 }
@@ -9356,7 +9365,6 @@ s390_irgen_MVC(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU64(length));
    s390_irgen_MVC_EX(len, start1, start2);
-   dummy_put_IA();
 
    return "mvc";
 }
@@ -9384,8 +9392,7 @@ s390_irgen_MVCL(UChar r1, UChar r2)
 
    /* len1 == 0 ? */
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, len1, len2, False);
-   if_condition_goto(binop(Iop_CmpEQ32, mkexpr(len1), mkU32(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32, mkexpr(len1), mkU32(0)));
 
    /* Check for destructive overlap:
       addr1 > addr2 && addr2 + len1 > addr1 && (addr2 + len2) > addr1 */
@@ -9405,12 +9412,11 @@ s390_irgen_MVCL(UChar r1, UChar r2)
                             binop(Iop_Add64, mkexpr(addr2),
                                   unop(Iop_32Uto64, mkexpr(len2))))));
 
-   if_condition_goto(binop(Iop_CmpEQ32,
-                           binop(Iop_And32,
-                                 binop(Iop_And32, mkexpr(cond1), mkexpr(cond2)),
-                                 mkexpr(cond3)),
-                           mkU32(1)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32,
+                      binop(Iop_And32,
+                            binop(Iop_And32, mkexpr(cond1), mkexpr(cond2)),
+                            mkexpr(cond3)),
+                      mkU32(1)));
 
    /* See s390_irgen_CLCL for explanation why we cannot load directly
       and need two steps. */
@@ -9440,8 +9446,7 @@ s390_irgen_MVCL(UChar r1, UChar r2)
                     binop(Iop_Sub32, mkexpr(r2p1), mkU32(1))));
 
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, len1, len2, False);
-   if_condition_goto(binop(Iop_CmpNE32, mkexpr(len1), mkU32(1)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE32, mkexpr(len1), mkU32(1)));
 
    return "mvcl";
 }
@@ -9466,8 +9471,7 @@ s390_irgen_MVCLE(UChar r1, UChar r3, IRTemp pad2)
 
    // len1 == 0 ?
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, len1, len3, False);
-   if_condition_goto(binop(Iop_CmpEQ64,mkexpr(len1), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64,mkexpr(len1), mkU64(0)));
 
    /* This is a hack to prevent mvcle from reading from addr3 if it
       should read from the pad. Since the pad has no address, just
@@ -9496,8 +9500,7 @@ s390_irgen_MVCLE(UChar r1, UChar r3, IRTemp pad2)
                      mkU64(0), binop(Iop_Sub64, mkexpr(len3), mkU64(1))));
 
    s390_cc_thunk_put2(S390_CC_OP_UNSIGNED_COMPARE, len1, len3, False);
-   if_condition_goto(binop(Iop_CmpNE64, mkexpr(len1), mkU64(1)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE64, mkexpr(len1), mkU64(1)));
 
    return "mvcle";
 }
@@ -9520,14 +9523,12 @@ s390_irgen_MVST(UChar r1, UChar r2)
 
    // We use unlimited as cpu-determined number
    put_counter_dw0(binop(Iop_Add64, mkexpr(counter), mkU64(1)));
-   if_condition_goto(binop(Iop_CmpNE8, mkexpr(end), mkexpr(byte)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE8, mkexpr(end), mkexpr(byte)));
 
    // and always set cc=1 at the end + update r1
    s390_cc_set(1);
    put_gpr_dw0(r1, binop(Iop_Add64, mkexpr(addr1), mkexpr(counter)));
    put_counter_dw0(mkU64(0));
-   dummy_put_IA();
 
    return "mvst";
 }
@@ -9793,9 +9794,7 @@ s390_irgen_cas_32(UChar r1, UChar r3, IRTemp op2addr)
       Otherwise, store the old_value from memory in r1 and yield. */
    assign(nequal, binop(Iop_CmpNE32, s390_call_calculate_cc(), mkU32(0)));
    put_gpr_w1(r1, mkite(mkexpr(nequal), mkexpr(old_mem), mkexpr(op1)));
-   stmt(IRStmt_Exit(mkexpr(nequal), Ijk_Yield,
-                    IRConst_U64(guest_IA_next_instr),
-                    S390X_GUEST_OFFSET(guest_IA)));
+   yield_if(mkexpr(nequal));
 }
 
 static HChar *
@@ -9843,9 +9842,7 @@ s390_irgen_CSG(UChar r1, UChar r3, IRTemp op2addr)
       Otherwise, store the old_value from memory in r1 and yield. */
    assign(nequal, binop(Iop_CmpNE32, s390_call_calculate_cc(), mkU32(0)));
    put_gpr_dw0(r1, mkite(mkexpr(nequal), mkexpr(old_mem), mkexpr(op1)));
-   stmt(IRStmt_Exit(mkexpr(nequal), Ijk_Yield,
-                    IRConst_U64(guest_IA_next_instr),
-                    S390X_GUEST_OFFSET(guest_IA)));
+   yield_if(mkexpr(nequal));
 
    return "csg";
 }
@@ -9892,9 +9889,7 @@ s390_irgen_cdas_32(UChar r1, UChar r3, IRTemp op2addr)
    assign(nequal, binop(Iop_CmpNE32, s390_call_calculate_cc(), mkU32(0)));
    put_gpr_w1(r1,   mkite(mkexpr(nequal), mkexpr(old_mem_high), mkexpr(op1_high)));
    put_gpr_w1(r1+1, mkite(mkexpr(nequal), mkexpr(old_mem_low),  mkexpr(op1_low)));
-   stmt(IRStmt_Exit(mkexpr(nequal), Ijk_Yield,
-                    IRConst_U64(guest_IA_next_instr),
-                    S390X_GUEST_OFFSET(guest_IA)));
+   yield_if(mkexpr(nequal));
 }
 
 static HChar *
@@ -9954,9 +9949,8 @@ s390_irgen_CDSG(UChar r1, UChar r3, IRTemp op2addr)
    assign(nequal, binop(Iop_CmpNE32, s390_call_calculate_cc(), mkU32(0)));
    put_gpr_dw0(r1,   mkite(mkexpr(nequal), mkexpr(old_mem_high), mkexpr(op1_high)));
    put_gpr_dw0(r1+1, mkite(mkexpr(nequal), mkexpr(old_mem_low),  mkexpr(op1_low)));
-   stmt(IRStmt_Exit(mkexpr(nequal), Ijk_Yield,
-                    IRConst_U64(guest_IA_next_instr),
-                    S390X_GUEST_OFFSET(guest_IA)));
+   yield_if(mkexpr(nequal));
+
    return "cdsg";
 }
 
@@ -10841,8 +10835,7 @@ s390_irgen_CKSM(UChar r1,UChar r2)
    s390_cc_set(0);
 
    /* If length is zero, there is no need to calculate the checksum */
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(len), mkU64(0)));
 
    /* Assiging the increment variable to adjust address and length
       later on. */
@@ -10880,8 +10873,7 @@ s390_irgen_CKSM(UChar r1,UChar r2)
    put_gpr_dw0(r2, binop(Iop_Add64, mkexpr(addr), mkexpr(inc)));
    put_gpr_dw0(r2+1, binop(Iop_Sub64, mkexpr(len), mkexpr(inc)));
 
-   if_condition_goto(binop(Iop_CmpNE64, mkexpr(len), mkU64(0)),
-                     guest_IA_curr_instr);
+   iterate_if(binop(Iop_CmpNE64, mkexpr(len), mkU64(0)));
 
    return "cksm";
 }
@@ -10908,8 +10900,7 @@ s390_irgen_TROO(UChar m3, UChar r1, UChar r2)
 
    /* End of source string? We're done; proceed to next insn */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)));
 
    /* Load character from source string, index translation table and
       store translated character in op1. */
@@ -10921,8 +10912,7 @@ s390_irgen_TROO(UChar m3, UChar r1, UChar r2)
 
    if (! s390_host_has_etf2 || (m3 & 0x1) == 0) {
       s390_cc_set(1);
-      if_condition_goto(binop(Iop_CmpEQ8, mkexpr(op1), mkexpr(test_byte)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ8, mkexpr(op1), mkexpr(test_byte)));
    }
    store(get_gpr_dw0(r1), mkexpr(op1));
 
@@ -10930,7 +10920,7 @@ s390_irgen_TROO(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r2, binop(Iop_Add64, mkexpr(src_addr), mkU64(1)));
    put_gpr_dw0(r1+1, binop(Iop_Sub64, mkexpr(src_len), mkU64(1)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "troo";
 }
@@ -10957,8 +10947,7 @@ s390_irgen_TRTO(UChar m3, UChar r1, UChar r2)
 
    /* End of source string? We're done; proceed to next insn */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)));
 
    /* Load character from source string, index translation table and
       store translated character in op1. */
@@ -10971,8 +10960,7 @@ s390_irgen_TRTO(UChar m3, UChar r1, UChar r2)
 
    if (! s390_host_has_etf2 || (m3 & 0x1) == 0) {
       s390_cc_set(1);
-      if_condition_goto(binop(Iop_CmpEQ8, mkexpr(op1), mkexpr(test_byte)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ8, mkexpr(op1), mkexpr(test_byte)));
    }
    store(get_gpr_dw0(r1), mkexpr(op1));
 
@@ -10980,7 +10968,7 @@ s390_irgen_TRTO(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r1, binop(Iop_Add64, mkexpr(des_addr), mkU64(1)));
    put_gpr_dw0(r1+1, binop(Iop_Sub64, mkexpr(src_len), mkU64(2)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "trto";
 }
@@ -11007,8 +10995,7 @@ s390_irgen_TROT(UChar m3, UChar r1, UChar r2)
 
    /* End of source string? We're done; proceed to next insn */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)));
 
    /* Load character from source string, index translation table and
       store translated character in op1. */
@@ -11020,8 +11007,7 @@ s390_irgen_TROT(UChar m3, UChar r1, UChar r2)
 
    if (! s390_host_has_etf2 || (m3 & 0x1) == 0) {
       s390_cc_set(1);
-      if_condition_goto(binop(Iop_CmpEQ16, mkexpr(op1), mkexpr(test_byte)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ16, mkexpr(op1), mkexpr(test_byte)));
    }
    store(get_gpr_dw0(r1), mkexpr(op1));
 
@@ -11029,7 +11015,7 @@ s390_irgen_TROT(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r1, binop(Iop_Add64, mkexpr(des_addr), mkU64(2)));
    put_gpr_dw0(r1+1, binop(Iop_Sub64, mkexpr(src_len), mkU64(1)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "trot";
 }
@@ -11056,8 +11042,7 @@ s390_irgen_TRTT(UChar m3, UChar r1, UChar r2)
 
    /* End of source string? We're done; proceed to next insn */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)));
 
    /* Load character from source string, index translation table and
       store translated character in op1. */
@@ -11069,8 +11054,7 @@ s390_irgen_TRTT(UChar m3, UChar r1, UChar r2)
 
    if (! s390_host_has_etf2 || (m3 & 0x1) == 0) {
       s390_cc_set(1);
-      if_condition_goto(binop(Iop_CmpEQ16, mkexpr(op1), mkexpr(test_byte)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ16, mkexpr(op1), mkexpr(test_byte)));
    }
 
    store(get_gpr_dw0(r1), mkexpr(op1));
@@ -11079,7 +11063,7 @@ s390_irgen_TRTT(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r1, binop(Iop_Add64, mkexpr(des_addr), mkU64(2)));
    put_gpr_dw0(r1+1, binop(Iop_Sub64, mkexpr(src_len), mkU64(2)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "trtt";
 }
@@ -11091,7 +11075,6 @@ s390_irgen_TR(UChar length, IRTemp start1, IRTemp start2)
 
    assign(len, mkU64(length));
    s390_irgen_TR_EX(len, start1, start2);
-   dummy_put_IA();
 
    return "tr";
 }
@@ -11116,15 +11099,13 @@ s390_irgen_TRE(UChar r1,UChar r2)
 
    /* End of source string? We're done; proceed to next insn */   
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ64, mkexpr(src_len), mkU64(0)));
 
    /* Load character from source string and compare with test byte */
    assign(op, load(Ity_I8, mkexpr(src_addr)));
    
    s390_cc_set(1);
-   if_condition_goto(binop(Iop_CmpEQ8, mkexpr(op), mkexpr(test_byte)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ8, mkexpr(op), mkexpr(test_byte)));
 
    assign(result, binop(Iop_Add64, unop(Iop_8Uto64, mkexpr(op)), 
                        mkexpr(tab_addr)));
@@ -11135,7 +11116,7 @@ s390_irgen_TRE(UChar r1,UChar r2)
    put_gpr_dw0(r1, binop(Iop_Add64, mkexpr(src_addr), mkU64(1)));
    put_gpr_dw0(r1+1, binop(Iop_Sub64, mkexpr(src_len), mkU64(1)));
 
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "tre";
 }
@@ -11171,8 +11152,7 @@ s390_irgen_CU21(UChar m3, UChar r1, UChar r2)
       there are less than 2 bytes left, then the 2nd operand is exhausted
       and we're done here. cc = 0 */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(2)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(2)));
 
    /* There are at least two bytes there. Read them. */
    IRTemp srcval = newTemp(Ity_I32);
@@ -11192,10 +11172,9 @@ s390_irgen_CU21(UChar m3, UChar r1, UChar r2)
    IRExpr *not_enough_bytes =
       mkite(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(4)), mkU32(1), mkU32(0));
 
-   if_condition_goto(binop(Iop_CmpEQ32,
-                           binop(Iop_And32, mkexpr(is_high_surrogate),
-                                 not_enough_bytes),
-                           mkU32(1)), guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32,
+                      binop(Iop_And32, mkexpr(is_high_surrogate),
+                            not_enough_bytes), mkU32(1)));
 
    /* The 2nd operand is not exhausted. If the first 2 bytes are a high
       surrogate, read the next two bytes (low surrogate). */
@@ -11218,8 +11197,7 @@ s390_irgen_CU21(UChar m3, UChar r1, UChar r2)
          binop(Iop_And64, mkexpr(retval), mkU64(0xff));
 
       s390_cc_set(2);
-      if_condition_goto(binop(Iop_CmpEQ64, invalid_low_surrogate, mkU64(1)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ64, invalid_low_surrogate, mkU64(1)));
    }
 
    /* Now test whether the 1st operand is exhausted */
@@ -11228,8 +11206,7 @@ s390_irgen_CU21(UChar m3, UChar r1, UChar r2)
                            binop(Iop_Shr64, mkexpr(retval), mkU8(8)),
                            mkU64(0xff)));
    s390_cc_set(1);
-   if_condition_goto(binop(Iop_CmpLT64U, mkexpr(len1), mkexpr(num_bytes)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT64U, mkexpr(len1), mkexpr(num_bytes)));
 
    /* Extract the bytes to be stored at addr1 */
    IRTemp data = newTemp(Ity_I64);
@@ -11265,8 +11242,7 @@ s390_irgen_CU21(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r1,     binop(Iop_Add64, mkexpr(addr1), mkexpr(num_bytes)));
    put_gpr_dw0(r1 + 1, binop(Iop_Sub64, mkexpr(len1),  mkexpr(num_bytes)));
 
-   /* Iterate */
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "cu21";
 }
@@ -11302,8 +11278,7 @@ s390_irgen_CU24(UChar m3, UChar r1, UChar r2)
       there are less than 2 bytes left, then the 2nd operand is exhausted
       and we're done here. cc = 0 */
    s390_cc_set(0);
-   if_condition_goto(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(2)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(2)));
 
    /* There are at least two bytes there. Read them. */
    IRTemp srcval = newTemp(Ity_I32);
@@ -11323,10 +11298,10 @@ s390_irgen_CU24(UChar m3, UChar r1, UChar r2)
    IRExpr *not_enough_bytes =
       mkite(binop(Iop_CmpLT64U, mkexpr(len2), mkU64(4)), mkU32(1), mkU32(0));
 
-   if_condition_goto(binop(Iop_CmpEQ32,
-                           binop(Iop_And32, mkexpr(is_high_surrogate),
-                                 not_enough_bytes),
-                           mkU32(1)), guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpEQ32,
+                      binop(Iop_And32, mkexpr(is_high_surrogate),
+                            not_enough_bytes),
+                      mkU32(1)));
 
    /* The 2nd operand is not exhausted. If the first 2 bytes are a high
       surrogate, read the next two bytes (low surrogate). */
@@ -11349,14 +11324,12 @@ s390_irgen_CU24(UChar m3, UChar r1, UChar r2)
          binop(Iop_And64, mkexpr(retval), mkU64(0xff));
 
       s390_cc_set(2);
-      if_condition_goto(binop(Iop_CmpEQ64, invalid_low_surrogate, mkU64(1)),
-                        guest_IA_next_instr);
+      next_insn_if(binop(Iop_CmpEQ64, invalid_low_surrogate, mkU64(1)));
    }
 
    /* Now test whether the 1st operand is exhausted */
    s390_cc_set(1);
-   if_condition_goto(binop(Iop_CmpLT64U, mkexpr(len1), mkU64(4)),
-                     guest_IA_next_instr);
+   next_insn_if(binop(Iop_CmpLT64U, mkexpr(len1), mkU64(4)));
 
    /* Extract the bytes to be stored at addr1 */
    IRExpr *data = unop(Iop_64to32, binop(Iop_Shr64, mkexpr(retval), mkU8(8)));
@@ -11375,8 +11348,7 @@ s390_irgen_CU24(UChar m3, UChar r1, UChar r2)
    put_gpr_dw0(r1,     binop(Iop_Add64, mkexpr(addr1), mkU64(4)));
    put_gpr_dw0(r1 + 1, binop(Iop_Sub64, mkexpr(len1),  mkU64(4)));
 
-   /* Iterate */
-   always_goto_and_chase(guest_IA_curr_instr);
+   iterate();
 
    return "cu24";
 }