Re: [PATCH 05/11] tcg/riscv: Use ADD.UW for guest address generation

[Daniel Henrique Barboza]

On 5/3/23 05:56, Richard Henderson wrote:

The instruction is a combined zero-extend and add.
Use it for exactly that.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
  tcg/riscv/tcg-target.c.inc | 33 ++++++++++++++++++++++-----------
  1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 53a7f97b29..f64eaa8515 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -1039,14 +1039,18 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext 
*s, TCGReg *pbase,
      tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP0, TCG_REG_TMP1, 0);

/* TLB Hit - translate address using addend. */

-    addr_adj = addr_reg;
-    if (TARGET_LONG_BITS == 32) {
-        addr_adj = TCG_REG_TMP0;
-        tcg_out_ext32u(s, addr_adj, addr_reg);
+    if (TARGET_LONG_BITS == 64) {
+        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, addr_reg, TCG_REG_TMP2);
+    } else if (have_zba) {
+        tcg_out_opc_reg(s, OPC_ADD_UW, TCG_REG_TMP0, addr_reg, TCG_REG_TMP2);
+    } else {
+        tcg_out_ext32u(s, TCG_REG_TMP0, addr_reg);
+        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_REG_TMP0, TCG_REG_TMP2);
      }
-    tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_REG_TMP2, addr_adj);
      *pbase = TCG_REG_TMP0;
  #else
+    TCGReg base;
+
      if (a_mask) {
          ldst = new_ldst_label(s);
          ldst->is_ld = is_ld;
@@ -1061,14 +1065,21 @@ static TCGLabelQemuLdst *prepare_host_addr(TCGContext 
*s, TCGReg *pbase,
          tcg_out_opc_branch(s, OPC_BNE, TCG_REG_TMP1, TCG_REG_ZERO, 0);
      }

- TCGReg base = addr_reg;

-    if (TARGET_LONG_BITS == 32) {
-        tcg_out_ext32u(s, TCG_REG_TMP0, base);
-        base = TCG_REG_TMP0;
-    }
      if (guest_base != 0) {
-        tcg_out_opc_reg(s, OPC_ADD, TCG_REG_TMP0, TCG_GUEST_BASE_REG, base);
          base = TCG_REG_TMP0;
+        if (TARGET_LONG_BITS == 64) {
+            tcg_out_opc_reg(s, OPC_ADD, base, addr_reg, TCG_GUEST_BASE_REG);
+        } else if (have_zba) {
+            tcg_out_opc_reg(s, OPC_ADD_UW, base, addr_reg, TCG_GUEST_BASE_REG);
+        } else {
+            tcg_out_ext32u(s, base, addr_reg);
+            tcg_out_opc_reg(s, OPC_ADD, base, base, TCG_GUEST_BASE_REG);
+        }
+    } else if (TARGET_LONG_BITS == 64) {
+        base = addr_reg;
+    } else {
+        base = TCG_REG_TMP0;
+        tcg_out_ext32u(s, base, addr_reg);

I tried to find a way to remove some of these IFs but all my alternatives 
weren't
much better.


Reviewed-by: Daniel Henrique Barboza <dbarb...@ventanamicro.com>

      }
      *pbase = base;
  #endif