[PATCH v3 29/29] tcg/riscv: Remove MO_BSWAP handling

[Richard Henderson <richard.henderson@linaro.org>]

TCG_TARGET_HAS_MEMORY_BSWAP is already unset for this backend,
which means that MO_BSWAP be handled by the middle-end and
will never be seen by the backend.  Thus the indexes used with
qemu_{ld,st}_helpers will always be zero.

Tidy the comments and asserts in tcg_out_qemu_{ld,st}_direct.
It is not that we do not handle bswap "yet", but never will.

Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/riscv/tcg-target.c.inc | 64 ++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 31 deletions(-)

diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index da7eecafc5..c16f96b401 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -852,37 +852,43 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
 /* helper signature: helper_ret_ld_mmu(CPUState *env, target_ulong addr,
  *                                     TCGMemOpIdx oi, uintptr_t ra)
  */
-static void * const qemu_ld_helpers[16] = {
-    [MO_UB]   = helper_ret_ldub_mmu,
-    [MO_SB]   = helper_ret_ldsb_mmu,
-    [MO_LEUW] = helper_le_lduw_mmu,
-    [MO_LESW] = helper_le_ldsw_mmu,
-    [MO_LEUL] = helper_le_ldul_mmu,
+static void * const qemu_ld_helpers[8] = {
+    [MO_UB] = helper_ret_ldub_mmu,
+    [MO_SB] = helper_ret_ldsb_mmu,
+#ifdef HOST_WORDS_BIGENDIAN
+    [MO_UW] = helper_be_lduw_mmu,
+    [MO_SW] = helper_be_ldsw_mmu,
+    [MO_UL] = helper_be_ldul_mmu,
 #if TCG_TARGET_REG_BITS == 64
-    [MO_LESL] = helper_le_ldsl_mmu,
+    [MO_SL] = helper_be_ldsl_mmu,
 #endif
-    [MO_LEQ]  = helper_le_ldq_mmu,
-    [MO_BEUW] = helper_be_lduw_mmu,
-    [MO_BESW] = helper_be_ldsw_mmu,
-    [MO_BEUL] = helper_be_ldul_mmu,
+    [MO_Q]  = helper_be_ldq_mmu,
+#else
+    [MO_UW] = helper_le_lduw_mmu,
+    [MO_SW] = helper_le_ldsw_mmu,
+    [MO_UL] = helper_le_ldul_mmu,
 #if TCG_TARGET_REG_BITS == 64
-    [MO_BESL] = helper_be_ldsl_mmu,
+    [MO_SL] = helper_le_ldsl_mmu,
+#endif
+    [MO_Q]  = helper_le_ldq_mmu,
 #endif
-    [MO_BEQ]  = helper_be_ldq_mmu,
 };
 
 /* helper signature: helper_ret_st_mmu(CPUState *env, target_ulong addr,
  *                                     uintxx_t val, TCGMemOpIdx oi,
  *                                     uintptr_t ra)
  */
-static void * const qemu_st_helpers[16] = {
-    [MO_UB]   = helper_ret_stb_mmu,
-    [MO_LEUW] = helper_le_stw_mmu,
-    [MO_LEUL] = helper_le_stl_mmu,
-    [MO_LEQ]  = helper_le_stq_mmu,
-    [MO_BEUW] = helper_be_stw_mmu,
-    [MO_BEUL] = helper_be_stl_mmu,
-    [MO_BEQ]  = helper_be_stq_mmu,
+static void * const qemu_st_helpers[4] = {
+    [MO_8]   = helper_ret_stb_mmu,
+#ifdef HOST_WORDS_BIGENDIAN
+    [MO_16] = helper_be_stw_mmu,
+    [MO_32] = helper_be_stl_mmu,
+    [MO_64] = helper_be_stq_mmu,
+#else
+    [MO_16] = helper_le_stw_mmu,
+    [MO_32] = helper_le_stl_mmu,
+    [MO_64] = helper_le_stq_mmu,
+#endif
 };
 
 /* We don't support oversize guests */
@@ -997,7 +1003,7 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
     tcg_out_movi(s, TCG_TYPE_PTR, a2, oi);
     tcg_out_movi(s, TCG_TYPE_PTR, a3, (tcg_target_long)l->raddr);
 
-    tcg_out_call(s, qemu_ld_helpers[opc & (MO_BSWAP | MO_SSIZE)]);
+    tcg_out_call(s, qemu_ld_helpers[opc & MO_SSIZE]);
     tcg_out_mov(s, (opc & MO_SIZE) == MO_64, l->datalo_reg, a0);
 
     tcg_out_goto(s, l->raddr);
@@ -1042,7 +1048,7 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
     tcg_out_movi(s, TCG_TYPE_PTR, a3, oi);
     tcg_out_movi(s, TCG_TYPE_PTR, a4, (tcg_target_long)l->raddr);
 
-    tcg_out_call(s, qemu_st_helpers[opc & (MO_BSWAP | MO_SSIZE)]);
+    tcg_out_call(s, qemu_st_helpers[opc & MO_SIZE]);
 
     tcg_out_goto(s, l->raddr);
     return true;
@@ -1052,10 +1058,8 @@ static bool tcg_out_qemu_st_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
 static void tcg_out_qemu_ld_direct(TCGContext *s, TCGReg lo, TCGReg hi,
                                    TCGReg base, MemOp opc, bool is_64)
 {
-    const MemOp bswap = opc & MO_BSWAP;
-
-    /* We don't yet handle byteswapping, assert */
-    g_assert(!bswap);
+    /* Byte swapping is left to middle-end expansion. */
+    tcg_debug_assert((opc & MO_BSWAP) == 0);
 
     switch (opc & (MO_SSIZE)) {
     case MO_UB:
@@ -1139,10 +1143,8 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, bool is_64)
 static void tcg_out_qemu_st_direct(TCGContext *s, TCGReg lo, TCGReg hi,
                                    TCGReg base, MemOp opc)
 {
-    const MemOp bswap = opc & MO_BSWAP;
-
-    /* We don't yet handle byteswapping, assert */
-    g_assert(!bswap);
+    /* Byte swapping is left to middle-end expansion. */
+    tcg_debug_assert((opc & MO_BSWAP) == 0);
 
     switch (opc & (MO_SSIZE)) {
     case MO_8:
-- 
2.25.1