tcg/s390x: Simplify constraints on qemu_ld/st

Adjust the softmmu tlb to use R0+R1, not any of the normally available
registers.  Since we handle overlap betwen inputs and helper arguments,
we can allow any allocatable reg.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

3 files changed, 12 insertions, 27 deletions

diff --git a/tcg/s390x/tcg-target-con-set.h b/tcg/s390x/tcg-target-con-set.h
index 15f1c55103..ecc079bb6d 100644
--- a/tcg/s390x/tcg-target-con-set.h
+++ b/tcg/s390x/tcg-target-con-set.h
@@ -10,12 +10,10 @@
  * tcg-target-con-str.h; the constraint combination is inclusive or.
  */
 C_O0_I1(r)
-C_O0_I2(L, L)
 C_O0_I2(r, r)
 C_O0_I2(r, ri)
 C_O0_I2(r, rA)
 C_O0_I2(v, r)
-C_O1_I1(r, L)
 C_O1_I1(r, r)
 C_O1_I1(v, r)
 C_O1_I1(v, v)
diff --git a/tcg/s390x/tcg-target-con-str.h b/tcg/s390x/tcg-target-con-str.h
index 6fa64a1ed6..25675b449e 100644
--- a/tcg/s390x/tcg-target-con-str.h
+++ b/tcg/s390x/tcg-target-con-str.h
@@ -9,7 +9,6 @@
  * REGS(letter, register_mask)
  */
 REGS('r', ALL_GENERAL_REGS)
-REGS('L', ALL_GENERAL_REGS & ~SOFTMMU_RESERVE_REGS)
 REGS('v', ALL_VECTOR_REGS)
 REGS('o', 0xaaaa) /* odd numbered general regs */
 
diff --git a/tcg/s390x/tcg-target.c.inc b/tcg/s390x/tcg-target.c.inc
index dd13326670..aacbaf21d5 100644
--- a/tcg/s390x/tcg-target.c.inc
+++ b/tcg/s390x/tcg-target.c.inc
@@ -44,18 +44,6 @@
 #define ALL_GENERAL_REGS     MAKE_64BIT_MASK(0, 16)
 #define ALL_VECTOR_REGS      MAKE_64BIT_MASK(32, 32)
 
-/*
- * For softmmu, we need to avoid conflicts with the first 3
- * argument registers to perform the tlb lookup, and to call
- * the helper function.
- */
-#ifdef CONFIG_SOFTMMU
-#define SOFTMMU_RESERVE_REGS MAKE_64BIT_MASK(TCG_REG_R2, 3)
-#else
-#define SOFTMMU_RESERVE_REGS 0
-#endif
-
-
 /* Several places within the instruction set 0 means "no register"
    rather than TCG_REG_R0.  */
 #define TCG_REG_NONE    0
@@ -1814,13 +1802,13 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
     ldst->oi = oi;
     ldst->addrlo_reg = addr_reg;
 
-    tcg_out_sh64(s, RSY_SRLG, TCG_REG_R2, addr_reg, TCG_REG_NONE,
+    tcg_out_sh64(s, RSY_SRLG, TCG_TMP0, addr_reg, TCG_REG_NONE,
                  TARGET_PAGE_BITS - CPU_TLB_ENTRY_BITS);
 
     QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) > 0);
     QEMU_BUILD_BUG_ON(TLB_MASK_TABLE_OFS(0) < -(1 << 19));
-    tcg_out_insn(s, RXY, NG, TCG_REG_R2, TCG_AREG0, TCG_REG_NONE, mask_off);
-    tcg_out_insn(s, RXY, AG, TCG_REG_R2, TCG_AREG0, TCG_REG_NONE, table_off);
+    tcg_out_insn(s, RXY, NG, TCG_TMP0, TCG_AREG0, TCG_REG_NONE, mask_off);
+    tcg_out_insn(s, RXY, AG, TCG_TMP0, TCG_AREG0, TCG_REG_NONE, table_off);
 
     /*
      * For aligned accesses, we check the first byte and include the alignment
@@ -1830,10 +1818,10 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
     a_off = (a_bits >= s_bits ? 0 : s_mask - a_mask);
     tlb_mask = (uint64_t)TARGET_PAGE_MASK | a_mask;
     if (a_off == 0) {
-        tgen_andi_risbg(s, TCG_REG_R3, addr_reg, tlb_mask);
+        tgen_andi_risbg(s, TCG_REG_R0, addr_reg, tlb_mask);
     } else {
-        tcg_out_insn(s, RX, LA, TCG_REG_R3, addr_reg, TCG_REG_NONE, a_off);
-        tgen_andi(s, TCG_TYPE_TL, TCG_REG_R3, tlb_mask);
+        tcg_out_insn(s, RX, LA, TCG_REG_R0, addr_reg, TCG_REG_NONE, a_off);
+        tgen_andi(s, TCG_TYPE_TL, TCG_REG_R0, tlb_mask);
     }
 
     if (is_ld) {
@@ -1842,16 +1830,16 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext *s, HostAddress *h,
         ofs = offsetof(CPUTLBEntry, addr_write);
     }
     if (TARGET_LONG_BITS == 32) {
-        tcg_out_insn(s, RX, C, TCG_REG_R3, TCG_REG_R2, TCG_REG_NONE, ofs);
+        tcg_out_insn(s, RX, C, TCG_REG_R0, TCG_TMP0, TCG_REG_NONE, ofs);
     } else {
-        tcg_out_insn(s, RXY, CG, TCG_REG_R3, TCG_REG_R2, TCG_REG_NONE, ofs);
+        tcg_out_insn(s, RXY, CG, TCG_REG_R0, TCG_TMP0, TCG_REG_NONE, ofs);
     }
 
     tcg_out16(s, RI_BRC | (S390_CC_NE << 4));
     ldst->label_ptr[0] = s->code_ptr++;
 
-    h->index = TCG_REG_R2;
-    tcg_out_insn(s, RXY, LG, h->index, TCG_REG_R2, TCG_REG_NONE,
+    h->index = TCG_TMP0;
+    tcg_out_insn(s, RXY, LG, h->index, TCG_TMP0, TCG_REG_NONE,
                  offsetof(CPUTLBEntry, addend));
 
     if (TARGET_LONG_BITS == 32) {
@@ -3155,10 +3143,10 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
 
     case INDEX_op_qemu_ld_i32:
     case INDEX_op_qemu_ld_i64:
-        return C_O1_I1(r, L);
+        return C_O1_I1(r, r);
     case INDEX_op_qemu_st_i64:
     case INDEX_op_qemu_st_i32:
-        return C_O0_I2(L, L);
+        return C_O0_I2(r, r);
 
     case INDEX_op_deposit_i32:
     case INDEX_op_deposit_i64: