diff mbox series

[v2,02/21] target/riscv: Clean up division helpers

Message ID 20210817211803.283639-3-richard.henderson@linaro.org (mailing list archive)
State New, archived
Headers show
Series target/riscv: Use tcg_constant_* | expand

Commit Message

Richard Henderson Aug. 17, 2021, 9:17 p.m. UTC 
Utilize the condition in the movcond more; this allows some of
the setcond that were feeding into movcond to be removed.
Do not write into source1 and source2.  Re-name "condN" to "tempN"
and use the temporaries for more than holding conditions.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/riscv/translate.c | 137 +++++++++++++++++++--------------------
 1 file changed, 65 insertions(+), 72 deletions(-)

Comments

Bin Meng Aug. 18, 2021, 9:20 a.m. UTC | #1 
On Wed, Aug 18, 2021 at 5:18 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Utilize the condition in the movcond more; this allows some of
> the setcond that were feeding into movcond to be removed.
> Do not write into source1 and source2.  Re-name "condN" to "tempN"
> and use the temporaries for more than holding conditions.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/riscv/translate.c | 137 +++++++++++++++++++--------------------
>  1 file changed, 65 insertions(+), 72 deletions(-)
>
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 20a55c92fb..6ae7e140d0 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -213,106 +213,99 @@ static void gen_mulhsu(TCGv ret, TCGv arg1, TCGv arg2)
>
>  static void gen_div(TCGv ret, TCGv source1, TCGv source2)
>  {
> -    TCGv cond1, cond2, zeroreg, resultopt1;
> +    TCGv temp1, temp2, zero, one, mone, min;
> +
>      /*
>       * Handle by altering args to tcg_gen_div to produce req'd results:
> -     * For overflow: want source1 in source1 and 1 in source2
> -     * For div by zero: want -1 in source1 and 1 in source2 -> -1 result
> +     * For overflow: want source1 in temp1 and 1 in temp2
> +     * For div by zero: want -1 in temp1 and 1 in temp2 -> -1 result
>       */
> -    cond1 = tcg_temp_new();
> -    cond2 = tcg_temp_new();
> -    zeroreg = tcg_constant_tl(0);
> -    resultopt1 = tcg_temp_new();
> +    temp1 = tcg_temp_new();
> +    temp2 = tcg_temp_new();
> +    zero = tcg_constant_tl(0);
> +    one = tcg_constant_tl(1);
> +    mone = tcg_constant_tl(-1);
> +    min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
> +
> +    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
> +    tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);

nits: I would put temp1 before temp2

> +    tcg_gen_and_tl(temp1, temp1, temp2); /* temp1 = overflow */
> +    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, zero); /* temp2 = div0 */
> +    tcg_gen_or_tl(temp2, temp2, temp1);  /* temp2 = overflow | div0 */
>
> -    tcg_gen_movi_tl(resultopt1, (target_ulong)-1);
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)(~0L));
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1,
> -                        ((target_ulong)1) << (TARGET_LONG_BITS - 1));
> -    tcg_gen_and_tl(cond1, cond1, cond2); /* cond1 = overflow */
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, 0); /* cond2 = div 0 */
>      /* if div by zero, set source1 to -1, otherwise don't change */

%s/source1/temp1

> -    tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond2, zeroreg, source1,
> -            resultopt1);
> -    /* if overflow or div by zero, set source2 to 1, else don't change */
> -    tcg_gen_or_tl(cond1, cond1, cond2);
> -    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
> -    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
> -            resultopt1);
> -    tcg_gen_div_tl(ret, source1, source2);
> +    tcg_gen_movcond_tl(TCG_COND_NE, temp1, source2, zero, source1, mone);
>
> -    tcg_temp_free(cond1);
> -    tcg_temp_free(cond2);
> -    tcg_temp_free(resultopt1);
> +    /* if overflow or div by zero, set source2 to 1, else don't change */

%s/source2/temp2

> +    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, temp2, zero, source2, one);
> +
> +    tcg_gen_div_tl(ret, temp1, temp2);
> +
> +    tcg_temp_free(temp1);
> +    tcg_temp_free(temp2);
>  }
>
>  static void gen_divu(TCGv ret, TCGv source1, TCGv source2)
>  {
> -    TCGv cond1, zeroreg, resultopt1;
> -    cond1 = tcg_temp_new();
> +    TCGv temp1, temp2, zero, one, mone;
>
> -    zeroreg = tcg_constant_tl(0);
> -    resultopt1 = tcg_temp_new();
> +    temp1 = tcg_temp_new();
> +    temp2 = tcg_temp_new();
> +    zero = tcg_constant_tl(0);
> +    one = tcg_constant_tl(1);
> +    mone = tcg_constant_tl(-1);

-1 is not a possible return value of divu. This should be ULONG_MAX.

>
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0);
> -    tcg_gen_movi_tl(resultopt1, (target_ulong)-1);
> -    tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond1, zeroreg, source1,
> -            resultopt1);
> -    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
> -    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
> -            resultopt1);
> -    tcg_gen_divu_tl(ret, source1, source2);
> +    tcg_gen_movcond_tl(TCG_COND_NE, temp1, source2, zero, source1, mone);

not "mone" here

> +    tcg_gen_movcond_tl(TCG_COND_NE, temp2, source2, zero, source2, one);
> +    tcg_gen_divu_tl(ret, temp1, temp2);
>
> -    tcg_temp_free(cond1);
> -    tcg_temp_free(resultopt1);
> +    tcg_temp_free(temp1);
> +    tcg_temp_free(temp2);
>  }
>
>  static void gen_rem(TCGv ret, TCGv source1, TCGv source2)
>  {
> -    TCGv cond1, cond2, zeroreg, resultopt1;
> +    TCGv temp1, temp2, zero, one, mone, min;
>
> -    cond1 = tcg_temp_new();
> -    cond2 = tcg_temp_new();
> -    zeroreg = tcg_constant_tl(0);
> -    resultopt1 = tcg_temp_new();
> +    temp1 = tcg_temp_new();
> +    temp2 = tcg_temp_new();
> +    zero = tcg_constant_tl(0);
> +    one = tcg_constant_tl(1);
> +    mone = tcg_constant_tl(-1);
> +    min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
> +
> +    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
> +    tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);
> +    tcg_gen_and_tl(temp1, temp1, temp2); /* temp1 = overflow */
> +    tcg_gen_setcondi_tl(TCG_COND_EQ, temp2, source2, 0); /* temp2 = div0 */

Is there any difference here if using zero/setcond instead of
0/setcondi? If not, I would prefer using zero/setcond for consistency.

> +    tcg_gen_or_tl(temp2, temp2, temp1);  /* temp2 = overflow | div0 */
>
> -    tcg_gen_movi_tl(resultopt1, 1L);
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)-1);
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1,
> -                        (target_ulong)1 << (TARGET_LONG_BITS - 1));
> -    tcg_gen_and_tl(cond2, cond1, cond2); /* cond1 = overflow */
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0); /* cond2 = div 0 */
>      /* if overflow or div by zero, set source2 to 1, else don't change */
> -    tcg_gen_or_tl(cond2, cond1, cond2);
> -    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond2, zeroreg, source2,
> -            resultopt1);
> -    tcg_gen_rem_tl(resultopt1, source1, source2);
> -    /* if div by zero, just return the original dividend */
> -    tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
> -            source1);
> +    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, temp2, zero, source2, one);
> +    tcg_gen_rem_tl(temp1, temp1, temp2);

This is wrong as temp1 is not the dividend.

>
> -    tcg_temp_free(cond1);
> -    tcg_temp_free(cond2);
> -    tcg_temp_free(resultopt1);
> +    /* if div by zero, just return the original dividend */
> +    tcg_gen_movcond_tl(TCG_COND_NE, ret, source2, zero, temp1, source1);
> +
> +    tcg_temp_free(temp1);
> +    tcg_temp_free(temp2);
>  }
>
>  static void gen_remu(TCGv ret, TCGv source1, TCGv source2)
>  {
> -    TCGv cond1, zeroreg, resultopt1;
> -    cond1 = tcg_temp_new();
> -    zeroreg = tcg_constant_tl(0);
> -    resultopt1 = tcg_temp_new();
> +    TCGv temp2, zero, one;
> +
> +    temp2 = tcg_temp_new();
> +    zero = tcg_constant_tl(0);
> +    one = tcg_constant_tl(1);
> +
> +    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, source2, zero, source2, one);

This should be TCG_COND_NE.

> +    tcg_gen_remu_tl(temp2, source1, temp2);
>
> -    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
> -    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0);
> -    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
> -            resultopt1);
> -    tcg_gen_remu_tl(resultopt1, source1, source2);
>      /* if div by zero, just return the original dividend */
> -    tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
> -            source1);
> +    tcg_gen_movcond_tl(TCG_COND_NE, ret, source2, zero, temp2, source1);
>
> -    tcg_temp_free(cond1);
> -    tcg_temp_free(resultopt1);
> +    tcg_temp_free(temp2);
>  }
>
>  static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)

Regards,
Bin
diff mbox series

Patch

diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 20a55c92fb..6ae7e140d0 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -213,106 +213,99 @@  static void gen_mulhsu(TCGv ret, TCGv arg1, TCGv arg2)
 
 static void gen_div(TCGv ret, TCGv source1, TCGv source2)
 {
-    TCGv cond1, cond2, zeroreg, resultopt1;
+    TCGv temp1, temp2, zero, one, mone, min;
+
     /*
      * Handle by altering args to tcg_gen_div to produce req'd results:
-     * For overflow: want source1 in source1 and 1 in source2
-     * For div by zero: want -1 in source1 and 1 in source2 -> -1 result
+     * For overflow: want source1 in temp1 and 1 in temp2
+     * For div by zero: want -1 in temp1 and 1 in temp2 -> -1 result
      */
-    cond1 = tcg_temp_new();
-    cond2 = tcg_temp_new();
-    zeroreg = tcg_constant_tl(0);
-    resultopt1 = tcg_temp_new();
+    temp1 = tcg_temp_new();
+    temp2 = tcg_temp_new();
+    zero = tcg_constant_tl(0);
+    one = tcg_constant_tl(1);
+    mone = tcg_constant_tl(-1);
+    min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
+
+    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
+    tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);
+    tcg_gen_and_tl(temp1, temp1, temp2); /* temp1 = overflow */
+    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, zero); /* temp2 = div0 */
+    tcg_gen_or_tl(temp2, temp2, temp1);  /* temp2 = overflow | div0 */
 
-    tcg_gen_movi_tl(resultopt1, (target_ulong)-1);
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)(~0L));
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1,
-                        ((target_ulong)1) << (TARGET_LONG_BITS - 1));
-    tcg_gen_and_tl(cond1, cond1, cond2); /* cond1 = overflow */
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, 0); /* cond2 = div 0 */
     /* if div by zero, set source1 to -1, otherwise don't change */
-    tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond2, zeroreg, source1,
-            resultopt1);
-    /* if overflow or div by zero, set source2 to 1, else don't change */
-    tcg_gen_or_tl(cond1, cond1, cond2);
-    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
-    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
-            resultopt1);
-    tcg_gen_div_tl(ret, source1, source2);
+    tcg_gen_movcond_tl(TCG_COND_NE, temp1, source2, zero, source1, mone);
 
-    tcg_temp_free(cond1);
-    tcg_temp_free(cond2);
-    tcg_temp_free(resultopt1);
+    /* if overflow or div by zero, set source2 to 1, else don't change */
+    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, temp2, zero, source2, one);
+
+    tcg_gen_div_tl(ret, temp1, temp2);
+
+    tcg_temp_free(temp1);
+    tcg_temp_free(temp2);
 }
 
 static void gen_divu(TCGv ret, TCGv source1, TCGv source2)
 {
-    TCGv cond1, zeroreg, resultopt1;
-    cond1 = tcg_temp_new();
+    TCGv temp1, temp2, zero, one, mone;
 
-    zeroreg = tcg_constant_tl(0);
-    resultopt1 = tcg_temp_new();
+    temp1 = tcg_temp_new();
+    temp2 = tcg_temp_new();
+    zero = tcg_constant_tl(0);
+    one = tcg_constant_tl(1);
+    mone = tcg_constant_tl(-1);
 
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0);
-    tcg_gen_movi_tl(resultopt1, (target_ulong)-1);
-    tcg_gen_movcond_tl(TCG_COND_EQ, source1, cond1, zeroreg, source1,
-            resultopt1);
-    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
-    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
-            resultopt1);
-    tcg_gen_divu_tl(ret, source1, source2);
+    tcg_gen_movcond_tl(TCG_COND_NE, temp1, source2, zero, source1, mone);
+    tcg_gen_movcond_tl(TCG_COND_NE, temp2, source2, zero, source2, one);
+    tcg_gen_divu_tl(ret, temp1, temp2);
 
-    tcg_temp_free(cond1);
-    tcg_temp_free(resultopt1);
+    tcg_temp_free(temp1);
+    tcg_temp_free(temp2);
 }
 
 static void gen_rem(TCGv ret, TCGv source1, TCGv source2)
 {
-    TCGv cond1, cond2, zeroreg, resultopt1;
+    TCGv temp1, temp2, zero, one, mone, min;
 
-    cond1 = tcg_temp_new();
-    cond2 = tcg_temp_new();
-    zeroreg = tcg_constant_tl(0);
-    resultopt1 = tcg_temp_new();
+    temp1 = tcg_temp_new();
+    temp2 = tcg_temp_new();
+    zero = tcg_constant_tl(0);
+    one = tcg_constant_tl(1);
+    mone = tcg_constant_tl(-1);
+    min = tcg_constant_tl(1ull << (TARGET_LONG_BITS - 1));
+
+    tcg_gen_setcond_tl(TCG_COND_EQ, temp2, source2, mone);
+    tcg_gen_setcond_tl(TCG_COND_EQ, temp1, source1, min);
+    tcg_gen_and_tl(temp1, temp1, temp2); /* temp1 = overflow */
+    tcg_gen_setcondi_tl(TCG_COND_EQ, temp2, source2, 0); /* temp2 = div0 */
+    tcg_gen_or_tl(temp2, temp2, temp1);  /* temp2 = overflow | div0 */
 
-    tcg_gen_movi_tl(resultopt1, 1L);
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond2, source2, (target_ulong)-1);
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source1,
-                        (target_ulong)1 << (TARGET_LONG_BITS - 1));
-    tcg_gen_and_tl(cond2, cond1, cond2); /* cond1 = overflow */
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0); /* cond2 = div 0 */
     /* if overflow or div by zero, set source2 to 1, else don't change */
-    tcg_gen_or_tl(cond2, cond1, cond2);
-    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond2, zeroreg, source2,
-            resultopt1);
-    tcg_gen_rem_tl(resultopt1, source1, source2);
-    /* if div by zero, just return the original dividend */
-    tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
-            source1);
+    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, temp2, zero, source2, one);
+    tcg_gen_rem_tl(temp1, temp1, temp2);
 
-    tcg_temp_free(cond1);
-    tcg_temp_free(cond2);
-    tcg_temp_free(resultopt1);
+    /* if div by zero, just return the original dividend */
+    tcg_gen_movcond_tl(TCG_COND_NE, ret, source2, zero, temp1, source1);
+
+    tcg_temp_free(temp1);
+    tcg_temp_free(temp2);
 }
 
 static void gen_remu(TCGv ret, TCGv source1, TCGv source2)
 {
-    TCGv cond1, zeroreg, resultopt1;
-    cond1 = tcg_temp_new();
-    zeroreg = tcg_constant_tl(0);
-    resultopt1 = tcg_temp_new();
+    TCGv temp2, zero, one;
+
+    temp2 = tcg_temp_new();
+    zero = tcg_constant_tl(0);
+    one = tcg_constant_tl(1);
+
+    tcg_gen_movcond_tl(TCG_COND_EQ, temp2, source2, zero, source2, one);
+    tcg_gen_remu_tl(temp2, source1, temp2);
 
-    tcg_gen_movi_tl(resultopt1, (target_ulong)1);
-    tcg_gen_setcondi_tl(TCG_COND_EQ, cond1, source2, 0);
-    tcg_gen_movcond_tl(TCG_COND_EQ, source2, cond1, zeroreg, source2,
-            resultopt1);
-    tcg_gen_remu_tl(resultopt1, source1, source2);
     /* if div by zero, just return the original dividend */
-    tcg_gen_movcond_tl(TCG_COND_EQ, ret, cond1, zeroreg, resultopt1,
-            source1);
+    tcg_gen_movcond_tl(TCG_COND_NE, ret, source2, zero, temp2, source1);
 
-    tcg_temp_free(cond1);
-    tcg_temp_free(resultopt1);
+    tcg_temp_free(temp2);
 }
 
 static void gen_jal(DisasContext *ctx, int rd, target_ulong imm)