Re: [PATCH V6] Optimize '(X - N * M) / N' to 'X / N - M' if valid
Hi,
Richard Biener writes:
> On Fri, 1 Sep 2023, Jiufu Guo wrote:
>
>> Hi,
>>
>> Integer expression "(X - N * M) / N" can be optimized to "X / N - M" with
>> the below conditions:
>> 1. There is no wrap/overflow/underflow.
>>wrap/overflow/underflow breaks the arithmetic operation.
>> 2. "X - N * M" and "X" are not of opposite sign.
>>Here, the operation "/" would be "trunc_div", the fractional part is
>>discarded towards zero. If "X - N * M" and "X" are in different signs,
>>then trunc_div discards the fractional parts (of /N) in different
>>directions.
>>
>> Compare the previous version:
>> https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624801.html
>> This patch adds comments and update the pattern on "(t + C)" to be more
>> tight.
>>
>> Bootstrap & regtest pass on ppc64{,le} and x86_64.
>> Is this patch ok for trunk?
>>
>> BR,
>> Jeff (Jiufu Guo)
>>
>> PR tree-optimization/108757
>>
>> gcc/ChangeLog:
>>
>> * match.pd ((X - N * M) / N): New pattern.
>> ((X + N * M) / N): New pattern.
>> ((X + C) div_rshift N): New pattern.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.dg/pr108757-1.c: New test.
>> * gcc.dg/pr108757-2.c: New test.
>> * gcc.dg/pr108757.h: New test.
>>
>> ---
>> gcc/match.pd | 78 ++
>> gcc/testsuite/gcc.dg/pr108757-1.c | 18 +++
>> gcc/testsuite/gcc.dg/pr108757-2.c | 19 +++
>> gcc/testsuite/gcc.dg/pr108757.h | 233 ++
>> 4 files changed, 348 insertions(+)
>> create mode 100644 gcc/testsuite/gcc.dg/pr108757-1.c
>> create mode 100644 gcc/testsuite/gcc.dg/pr108757-2.c
>> create mode 100644 gcc/testsuite/gcc.dg/pr108757.h
>>
>> diff --git a/gcc/match.pd b/gcc/match.pd
>> index
>> fa598d5ca2e470f9cc3b82469e77d743b12f107e..863bc7299cdefc622a7806a4d32e37268c50d453
>> 100644
>> --- a/gcc/match.pd
>> +++ b/gcc/match.pd
>> @@ -959,6 +959,84 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>> #endif
>>
>>
>> +#if GIMPLE
>> +(for div (trunc_div exact_div)
>> + /* Simplify (X + M*N) / N -> X / N + M. */
>> + (simplify
>> + (div (plus:c@4 @0 (mult:c@3 @1 @2)) @2)
>> + (with {value_range vr0, vr1, vr2, vr3, vr4;}
>> + (if (INTEGRAL_TYPE_P (type)
>> + && get_range_query (cfun)->range_of_expr (vr1, @1)
>> + && get_range_query (cfun)->range_of_expr (vr2, @2)
>> + /* "N*M" doesn't overflow. */
>> + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
>> + && get_range_query (cfun)->range_of_expr (vr0, @0)
>> + && get_range_query (cfun)->range_of_expr (vr3, @3)
>> + /* "X+(N*M)" doesn't overflow. */
>> + && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr3)
>> + && get_range_query (cfun)->range_of_expr (vr4, @4)
>> + /* "X+N*M" is not with opposite sign as "X". */
>> + && (TYPE_UNSIGNED (type)
>> + || (vr0.nonnegative_p () && vr4.nonnegative_p ())
>> + || (vr0.nonpositive_p () && vr4.nonpositive_p (
>> + (plus (div @0 @2) @1
>> +
>> + /* Simplify (X - M*N) / N -> X / N - M. */
>> + (simplify
>> + (div (minus@4 @0 (mult:c@3 @1 @2)) @2)
>> + (with {value_range vr0, vr1, vr2, vr3, vr4;}
>> + (if (INTEGRAL_TYPE_P (type)
>> + && get_range_query (cfun)->range_of_expr (vr1, @1)
>> + && get_range_query (cfun)->range_of_expr (vr2, @2)
>> + /* "N * M" doesn't overflow. */
>> + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
>> + && get_range_query (cfun)->range_of_expr (vr0, @0)
>> + && get_range_query (cfun)->range_of_expr (vr3, @3)
>> + /* "X - (N*M)" doesn't overflow. */
>> + && range_op_handler (MINUS_EXPR).overflow_free_p (vr0, vr3)
>> + && get_range_query (cfun)->range_of_expr (vr4, @4)
>> + /* "X-N*M" is not with opposite sign as "X". */
>> + && (TYPE_UNSIGNED (type)
>> + || (vr0.nonnegative_p () && vr4.nonnegative_p ())
>> + || (vr0.nonpositive_p () && vr4.nonpositive_p (
>> + (minus (div @0 @2) @1)
>> +
>> +/* Simplify
>> + (X + C) / N -> X / N + C / N where C is multiple of N.
>> + (X + C) >> N -> X >> N + C>>N if low N bits of C is 0. */
>> +(for op (trunc_div exact_div rshift)
>> + (simplify
>> + (op (plus@3 @0 INTEGER_CST@1) INTEGER_CST@2)
>> + (with
>> +{
>> + wide_int c = wi::to_wide (@1);
>> + wide_int n = wi::to_wide (@2);
>> + bool shift = op == RSHIFT_EXPR;
>> + #define plus_op1(v) (shift ? wi::rshift (v, n, TYPE_SIGN (type)) \
>> + : wi::div_trunc (v, n, TYPE_SIGN (type)))
>> + #define exact_mod(v) (shift ? wi::ctz (v) >= n.to_shwi () \
>> + : wi::multiple_of_p (v, n, TYPE_SIGN (type)))
>
> please indent these full left
>
>> + value_range vr0, vr1, vr3;
>> +}
>> +(if (INTEGRAL_TYPE_P (type)
>> + && get_range_query (cfun)->range_of_expr (vr0, @0))
>> + (if (exact_mod (c)
>> + && get_range_query (cfun)->range_of_expr (vr1, @1)
>> +
Re: [PATCH V6] Optimize '(X - N * M) / N' to 'X / N - M' if valid
On Fri, 1 Sep 2023, Jiufu Guo wrote:
> Hi,
>
> Integer expression "(X - N * M) / N" can be optimized to "X / N - M" with
> the below conditions:
> 1. There is no wrap/overflow/underflow.
>wrap/overflow/underflow breaks the arithmetic operation.
> 2. "X - N * M" and "X" are not of opposite sign.
>Here, the operation "/" would be "trunc_div", the fractional part is
>discarded towards zero. If "X - N * M" and "X" are in different signs,
>then trunc_div discards the fractional parts (of /N) in different
>directions.
>
> Compare the previous version:
> https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624801.html
> This patch adds comments and update the pattern on "(t + C)" to be more
> tight.
>
> Bootstrap & regtest pass on ppc64{,le} and x86_64.
> Is this patch ok for trunk?
>
> BR,
> Jeff (Jiufu Guo)
>
> PR tree-optimization/108757
>
> gcc/ChangeLog:
>
> * match.pd ((X - N * M) / N): New pattern.
> ((X + N * M) / N): New pattern.
> ((X + C) div_rshift N): New pattern.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/pr108757-1.c: New test.
> * gcc.dg/pr108757-2.c: New test.
> * gcc.dg/pr108757.h: New test.
>
> ---
> gcc/match.pd | 78 ++
> gcc/testsuite/gcc.dg/pr108757-1.c | 18 +++
> gcc/testsuite/gcc.dg/pr108757-2.c | 19 +++
> gcc/testsuite/gcc.dg/pr108757.h | 233 ++
> 4 files changed, 348 insertions(+)
> create mode 100644 gcc/testsuite/gcc.dg/pr108757-1.c
> create mode 100644 gcc/testsuite/gcc.dg/pr108757-2.c
> create mode 100644 gcc/testsuite/gcc.dg/pr108757.h
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index
> fa598d5ca2e470f9cc3b82469e77d743b12f107e..863bc7299cdefc622a7806a4d32e37268c50d453
> 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -959,6 +959,84 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> #endif
>
>
> +#if GIMPLE
> +(for div (trunc_div exact_div)
> + /* Simplify (X + M*N) / N -> X / N + M. */
> + (simplify
> + (div (plus:c@4 @0 (mult:c@3 @1 @2)) @2)
> + (with {value_range vr0, vr1, vr2, vr3, vr4;}
> + (if (INTEGRAL_TYPE_P (type)
> + && get_range_query (cfun)->range_of_expr (vr1, @1)
> + && get_range_query (cfun)->range_of_expr (vr2, @2)
> + /* "N*M" doesn't overflow. */
> + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
> + && get_range_query (cfun)->range_of_expr (vr0, @0)
> + && get_range_query (cfun)->range_of_expr (vr3, @3)
> + /* "X+(N*M)" doesn't overflow. */
> + && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr3)
> + && get_range_query (cfun)->range_of_expr (vr4, @4)
> + /* "X+N*M" is not with opposite sign as "X". */
> + && (TYPE_UNSIGNED (type)
> +|| (vr0.nonnegative_p () && vr4.nonnegative_p ())
> +|| (vr0.nonpositive_p () && vr4.nonpositive_p (
> + (plus (div @0 @2) @1
> +
> + /* Simplify (X - M*N) / N -> X / N - M. */
> + (simplify
> + (div (minus@4 @0 (mult:c@3 @1 @2)) @2)
> + (with {value_range vr0, vr1, vr2, vr3, vr4;}
> + (if (INTEGRAL_TYPE_P (type)
> + && get_range_query (cfun)->range_of_expr (vr1, @1)
> + && get_range_query (cfun)->range_of_expr (vr2, @2)
> + /* "N * M" doesn't overflow. */
> + && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
> + && get_range_query (cfun)->range_of_expr (vr0, @0)
> + && get_range_query (cfun)->range_of_expr (vr3, @3)
> + /* "X - (N*M)" doesn't overflow. */
> + && range_op_handler (MINUS_EXPR).overflow_free_p (vr0, vr3)
> + && get_range_query (cfun)->range_of_expr (vr4, @4)
> + /* "X-N*M" is not with opposite sign as "X". */
> + && (TYPE_UNSIGNED (type)
> +|| (vr0.nonnegative_p () && vr4.nonnegative_p ())
> +|| (vr0.nonpositive_p () && vr4.nonpositive_p (
> + (minus (div @0 @2) @1)
> +
> +/* Simplify
> + (X + C) / N -> X / N + C / N where C is multiple of N.
> + (X + C) >> N -> X >> N + C>>N if low N bits of C is 0. */
> +(for op (trunc_div exact_div rshift)
> + (simplify
> + (op (plus@3 @0 INTEGER_CST@1) INTEGER_CST@2)
> + (with
> +{
> + wide_int c = wi::to_wide (@1);
> + wide_int n = wi::to_wide (@2);
> + bool shift = op == RSHIFT_EXPR;
> + #define plus_op1(v) (shift ? wi::rshift (v, n, TYPE_SIGN (type)) \
> + : wi::div_trunc (v, n, TYPE_SIGN (type)))
> + #define exact_mod(v) (shift ? wi::ctz (v) >= n.to_shwi () \
> + : wi::multiple_of_p (v, n, TYPE_SIGN (type)))
please indent these full left
> + value_range vr0, vr1, vr3;
> +}
> +(if (INTEGRAL_TYPE_P (type)
> + && get_range_query (cfun)->range_of_expr (vr0, @0))
> + (if (exact_mod (c)
> + && get_range_query (cfun)->range_of_expr (vr1, @1)
> + /* "X+C" doesn't overflow. */
> + && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr1)
> + && get_range_query
[PATCH V6] Optimize '(X - N * M) / N' to 'X / N - M' if valid
Hi,
Integer expression "(X - N * M) / N" can be optimized to "X / N - M" with
the below conditions:
1. There is no wrap/overflow/underflow.
wrap/overflow/underflow breaks the arithmetic operation.
2. "X - N * M" and "X" are not of opposite sign.
Here, the operation "/" would be "trunc_div", the fractional part is
discarded towards zero. If "X - N * M" and "X" are in different signs,
then trunc_div discards the fractional parts (of /N) in different
directions.
Compare the previous version:
https://gcc.gnu.org/pipermail/gcc-patches/2023-July/624801.html
This patch adds comments and update the pattern on "(t + C)" to be more
tight.
Bootstrap & regtest pass on ppc64{,le} and x86_64.
Is this patch ok for trunk?
BR,
Jeff (Jiufu Guo)
PR tree-optimization/108757
gcc/ChangeLog:
* match.pd ((X - N * M) / N): New pattern.
((X + N * M) / N): New pattern.
((X + C) div_rshift N): New pattern.
gcc/testsuite/ChangeLog:
* gcc.dg/pr108757-1.c: New test.
* gcc.dg/pr108757-2.c: New test.
* gcc.dg/pr108757.h: New test.
---
gcc/match.pd | 78 ++
gcc/testsuite/gcc.dg/pr108757-1.c | 18 +++
gcc/testsuite/gcc.dg/pr108757-2.c | 19 +++
gcc/testsuite/gcc.dg/pr108757.h | 233 ++
4 files changed, 348 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/pr108757-1.c
create mode 100644 gcc/testsuite/gcc.dg/pr108757-2.c
create mode 100644 gcc/testsuite/gcc.dg/pr108757.h
diff --git a/gcc/match.pd b/gcc/match.pd
index
fa598d5ca2e470f9cc3b82469e77d743b12f107e..863bc7299cdefc622a7806a4d32e37268c50d453
100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -959,6 +959,84 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
#endif
+#if GIMPLE
+(for div (trunc_div exact_div)
+ /* Simplify (X + M*N) / N -> X / N + M. */
+ (simplify
+ (div (plus:c@4 @0 (mult:c@3 @1 @2)) @2)
+ (with {value_range vr0, vr1, vr2, vr3, vr4;}
+ (if (INTEGRAL_TYPE_P (type)
+ && get_range_query (cfun)->range_of_expr (vr1, @1)
+ && get_range_query (cfun)->range_of_expr (vr2, @2)
+ /* "N*M" doesn't overflow. */
+ && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
+ && get_range_query (cfun)->range_of_expr (vr0, @0)
+ && get_range_query (cfun)->range_of_expr (vr3, @3)
+ /* "X+(N*M)" doesn't overflow. */
+ && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr3)
+ && get_range_query (cfun)->range_of_expr (vr4, @4)
+ /* "X+N*M" is not with opposite sign as "X". */
+ && (TYPE_UNSIGNED (type)
+ || (vr0.nonnegative_p () && vr4.nonnegative_p ())
+ || (vr0.nonpositive_p () && vr4.nonpositive_p (
+ (plus (div @0 @2) @1
+
+ /* Simplify (X - M*N) / N -> X / N - M. */
+ (simplify
+ (div (minus@4 @0 (mult:c@3 @1 @2)) @2)
+ (with {value_range vr0, vr1, vr2, vr3, vr4;}
+ (if (INTEGRAL_TYPE_P (type)
+ && get_range_query (cfun)->range_of_expr (vr1, @1)
+ && get_range_query (cfun)->range_of_expr (vr2, @2)
+ /* "N * M" doesn't overflow. */
+ && range_op_handler (MULT_EXPR).overflow_free_p (vr1, vr2)
+ && get_range_query (cfun)->range_of_expr (vr0, @0)
+ && get_range_query (cfun)->range_of_expr (vr3, @3)
+ /* "X - (N*M)" doesn't overflow. */
+ && range_op_handler (MINUS_EXPR).overflow_free_p (vr0, vr3)
+ && get_range_query (cfun)->range_of_expr (vr4, @4)
+ /* "X-N*M" is not with opposite sign as "X". */
+ && (TYPE_UNSIGNED (type)
+ || (vr0.nonnegative_p () && vr4.nonnegative_p ())
+ || (vr0.nonpositive_p () && vr4.nonpositive_p (
+ (minus (div @0 @2) @1)
+
+/* Simplify
+ (X + C) / N -> X / N + C / N where C is multiple of N.
+ (X + C) >> N -> X >> N + C>>N if low N bits of C is 0. */
+(for op (trunc_div exact_div rshift)
+ (simplify
+ (op (plus@3 @0 INTEGER_CST@1) INTEGER_CST@2)
+ (with
+{
+ wide_int c = wi::to_wide (@1);
+ wide_int n = wi::to_wide (@2);
+ bool shift = op == RSHIFT_EXPR;
+ #define plus_op1(v) (shift ? wi::rshift (v, n, TYPE_SIGN (type)) \
+: wi::div_trunc (v, n, TYPE_SIGN (type)))
+ #define exact_mod(v) (shift ? wi::ctz (v) >= n.to_shwi () \
+ : wi::multiple_of_p (v, n, TYPE_SIGN (type)))
+ value_range vr0, vr1, vr3;
+}
+(if (INTEGRAL_TYPE_P (type)
+&& get_range_query (cfun)->range_of_expr (vr0, @0))
+ (if (exact_mod (c)
+ && get_range_query (cfun)->range_of_expr (vr1, @1)
+ /* "X+C" doesn't overflow. */
+ && range_op_handler (PLUS_EXPR).overflow_free_p (vr0, vr1)
+ && get_range_query (cfun)->range_of_expr (vr3, @3)
+ /* "X+C" and "X" are not of opposite sign. */
+ && (TYPE_UNSIGNED (type)
+ || (vr0.nonnegative_p () && vr3.nonnegative_p ())
+ || (vr0.nonpositive_p () && vr3.nonpositive_p (
+ (plus (op @0 @2) {
