tcg/mips: Always implement movcond

Expand as branch over move if not supported in the ISA. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20231026041404.1229328-3-richard.henderson@linaro.org>
qemu · Nov 6, 2023 · 2cff741 · 2cff741
1 parent 42221a6
commit 2cff741
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Showing 2 changed files with 16 additions and 7 deletions.
diff --git a/tcg/mips/tcg-target.c.inc b/tcg/mips/tcg-target.c.inc
@@ -1070,13 +1070,22 @@ static void tcg_out_movcond(TCGContext *s, TCGCond cond, TCGReg ret,
         if (v2 != 0) {
             tcg_out_opc_reg(s, OPC_OR, ret, ret, TCG_TMP1);
         }
-    } else {
-        MIPSInsn m_opc = eqz ? OPC_MOVZ : OPC_MOVN;
+        return;
+    }
 
-        tcg_out_opc_reg(s, m_opc, ret, v1, c1);
+    /* This should be guaranteed via constraints */
+    tcg_debug_assert(v2 == ret);
 
-        /* This should be guaranteed via constraints */
-        tcg_debug_assert(v2 == ret);
+    if (use_movnz_instructions) {
+        MIPSInsn m_opc = eqz ? OPC_MOVZ : OPC_MOVN;
+        tcg_out_opc_reg(s, m_opc, ret, v1, c1);
+    } else {
+        /* Invert the condition in order to branch over the move. */
+        MIPSInsn b_opc = eqz ? OPC_BNE : OPC_BEQ;
+        tcg_out_opc_imm(s, b_opc, c1, TCG_REG_ZERO, 2);
+        tcg_out_nop(s);
+        /* Open-code tcg_out_mov, without the nop-move check. */
+        tcg_out_opc_reg(s, OPC_OR, ret, v1, TCG_REG_ZERO);
     }
 }
 

diff --git a/tcg/mips/tcg-target.h b/tcg/mips/tcg-target.h
@@ -154,7 +154,7 @@ extern bool use_mips32r2_instructions;
 #endif
 
 /* optional instructions detected at runtime */
-#define TCG_TARGET_HAS_movcond_i32      use_movnz_instructions
+#define TCG_TARGET_HAS_movcond_i32      1
 #define TCG_TARGET_HAS_bswap16_i32      use_mips32r2_instructions
 #define TCG_TARGET_HAS_deposit_i32      use_mips32r2_instructions
 #define TCG_TARGET_HAS_extract_i32      use_mips32r2_instructions
@@ -169,7 +169,7 @@ extern bool use_mips32r2_instructions;
 #define TCG_TARGET_HAS_qemu_st8_i32     0
 
 #if TCG_TARGET_REG_BITS == 64
-#define TCG_TARGET_HAS_movcond_i64      use_movnz_instructions
+#define TCG_TARGET_HAS_movcond_i64      1
 #define TCG_TARGET_HAS_bswap16_i64      use_mips32r2_instructions
 #define TCG_TARGET_HAS_bswap32_i64      use_mips32r2_instructions
 #define TCG_TARGET_HAS_bswap64_i64      use_mips32r2_instructions