Re: [PATCH] Improve pow (C, x) -> exp (log (C) * x) optimization (PR middle-end/84309, take 2)

[Richard Biener]

On Mon, 12 Feb 2018, Jakub Jelinek wrote:

> On Sat, Feb 10, 2018 at 03:26:46PM +0100, Jakub Jelinek wrote:
> > If use_exp2 is true and (cfun->curr_properties & PROP_gimple_lvec) == 0,
> > don't fold it?  Then I guess if we vectorize or slp vectorize the pow
> > as vector pow, we'd need to match.pd it into the exp (log (vec_cst) * x).
> 
> Here is an updated patch, that defers it for pow (0x2.0pN, x) until after
> vectorization and adds tree-vect-patterns.c matcher that will handle it
> during vectorization (that one using exp, because we don't have exp2
> vectorized).
> 
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Ok.

Thanks,
Richard.

> 2018-02-12  Jakub Jelinek  
> 
>   PR middle-end/84309
>   * match.pd (pow(C,x) -> exp(log(C)*x)): Optimize instead into
>   exp2(log2(C)*x) if C is a power of 2 and c99 runtime is available.
>   * generic-match-head.c (canonicalize_math_after_vectorization_p): New
>   inline function.
>   * gimple-match-head.c (canonicalize_math_after_vectorization_p): New
>   inline function.
>   * omp-simd-clone.h: New file.
>   * omp-simd-clone.c: Include omp-simd-clone.h.
>   (expand_simd_clones): No longer static.
>   * tree-vect-patterns.c: Include fold-const-call.h, attribs.h,
>   cgraph.h and omp-simd-clone.h.
>   (vect_recog_pow_pattern): Optimize pow(C,x) to exp(log(C)*x).
>   (vect_recog_widen_shift_pattern): Formatting fix.
>   (vect_pattern_recog_1): Don't check optab for calls.
> 
>   * gcc.dg/pr84309.c: New test.
>   * gcc.target/i386/pr84309.c: New test.
> 
> --- gcc/match.pd.jj   2018-02-09 19:11:26.910070491 +0100
> +++ gcc/match.pd  2018-02-12 14:15:05.653779352 +0100
> @@ -3992,15 +3992,36 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (logs (pows @0 @1))
> (mult @1 (logs @0
>  
> - /* pow(C,x) -> exp(log(C)*x) if C > 0.  */
> + /* pow(C,x) -> exp(log(C)*x) if C > 0,
> +or if C is a positive power of 2,
> +pow(C,x) -> exp2(log2(C)*x).  */
>   (for pows (POW)
>exps (EXP)
>logs (LOG)
> +  exp2s (EXP2)
> +  log2s (LOG2)
>(simplify
> (pows REAL_CST@0 @1)
> -(if (real_compare (GT_EXPR, TREE_REAL_CST_PTR (@0), )
> -  && real_isfinite (TREE_REAL_CST_PTR (@0)))
> - (exps (mult (logs @0) @1)
> +   (if (real_compare (GT_EXPR, TREE_REAL_CST_PTR (@0), )
> + && real_isfinite (TREE_REAL_CST_PTR (@0)))
> +(with {
> +   const REAL_VALUE_TYPE *const value = TREE_REAL_CST_PTR (@0);
> +   bool use_exp2 = false;
> +   if (targetm.libc_has_function (function_c99_misc)
> +&& value->cl == rvc_normal)
> +  {
> +REAL_VALUE_TYPE frac_rvt = *value;
> +SET_REAL_EXP (_rvt, 1);
> +if (real_equal (_rvt, ))
> +  use_exp2 = true;
> +  }
> + }
> + (if (!use_exp2)
> +  (exps (mult (logs @0) @1))
> +  /* As libmvec doesn't have a vectorized exp2, defer optimizing
> +  this until after vectorization.  */
> +  (if (canonicalize_math_after_vectorization_p ())
> + (exps (mult (logs @0) @1
>  
>   (for sqrts (SQRT)
>cbrts (CBRT)
> --- gcc/generic-match-head.c.jj   2018-01-03 10:19:55.454534005 +0100
> +++ gcc/generic-match-head.c  2018-02-12 14:13:27.088784495 +0100
> @@ -68,3 +68,12 @@ canonicalize_math_p ()
>  {
>return true;
>  }
> +
> +/* Return true if math operations that are beneficial only after
> +   vectorization should be canonicalized.  */
> +
> +static inline bool
> +canonicalize_math_after_vectorization_p ()
> +{
> +  return false;
> +}
> --- gcc/gimple-match-head.c.jj2018-01-03 10:19:55.931534081 +0100
> +++ gcc/gimple-match-head.c   2018-02-12 14:14:17.352781873 +0100
> @@ -831,3 +831,12 @@ canonicalize_math_p ()
>  {
>return !cfun || (cfun->curr_properties & PROP_gimple_opt_math) == 0;
>  }
> +
> +/* Return true if math operations that are beneficial only after
> +   vectorization should be canonicalized.  */
> +
> +static inline bool
> +canonicalize_math_after_vectorization_p ()
> +{
> +  return !cfun || (cfun->curr_properties & PROP_gimple_lvec) != 0;
> +}
> --- gcc/omp-simd-clone.h.jj   2018-02-12 18:11:01.843931808 +0100
> +++ gcc/omp-simd-clone.h  2018-02-12 18:12:13.901948041 +0100
> @@ -0,0 +1,26 @@
> +/* OMP constructs' SIMD clone supporting code.
> +
> +   Copyright (C) 2005-2018 Free Software Foundation, Inc.
> +
> +This file is part of GCC.
> +
> +GCC is free software; you can redistribute it and/or modify it under
> +the terms of the GNU General Public License as published by the Free
> +Software Foundation; either version 3, or (at your option) any later
> +version.
> +
> +GCC is distributed in the hope that it will be useful, but WITHOUT ANY
> +WARRANTY; without even the implied warranty of MERCHANTABILITY or
> +FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
> +for more details.
> +
> +You should have received a copy of the GNU General Public 

[PATCH] Improve pow (C, x) -> exp (log (C) * x) optimization (PR middle-end/84309, take 2)

[Jakub Jelinek]

On Sat, Feb 10, 2018 at 03:26:46PM +0100, Jakub Jelinek wrote:
> If use_exp2 is true and (cfun->curr_properties & PROP_gimple_lvec) == 0,
> don't fold it?  Then I guess if we vectorize or slp vectorize the pow
> as vector pow, we'd need to match.pd it into the exp (log (vec_cst) * x).

Here is an updated patch, that defers it for pow (0x2.0pN, x) until after
vectorization and adds tree-vect-patterns.c matcher that will handle it
during vectorization (that one using exp, because we don't have exp2
vectorized).

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2018-02-12  Jakub Jelinek  

PR middle-end/84309
* match.pd (pow(C,x) -> exp(log(C)*x)): Optimize instead into
exp2(log2(C)*x) if C is a power of 2 and c99 runtime is available.
* generic-match-head.c (canonicalize_math_after_vectorization_p): New
inline function.
* gimple-match-head.c (canonicalize_math_after_vectorization_p): New
inline function.
* omp-simd-clone.h: New file.
* omp-simd-clone.c: Include omp-simd-clone.h.
(expand_simd_clones): No longer static.
* tree-vect-patterns.c: Include fold-const-call.h, attribs.h,
cgraph.h and omp-simd-clone.h.
(vect_recog_pow_pattern): Optimize pow(C,x) to exp(log(C)*x).
(vect_recog_widen_shift_pattern): Formatting fix.
(vect_pattern_recog_1): Don't check optab for calls.

* gcc.dg/pr84309.c: New test.
* gcc.target/i386/pr84309.c: New test.

--- gcc/match.pd.jj 2018-02-09 19:11:26.910070491 +0100
+++ gcc/match.pd2018-02-12 14:15:05.653779352 +0100
@@ -3992,15 +3992,36 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(logs (pows @0 @1))
(mult @1 (logs @0
 
- /* pow(C,x) -> exp(log(C)*x) if C > 0.  */
+ /* pow(C,x) -> exp(log(C)*x) if C > 0,
+or if C is a positive power of 2,
+pow(C,x) -> exp2(log2(C)*x).  */
  (for pows (POW)
   exps (EXP)
   logs (LOG)
+  exp2s (EXP2)
+  log2s (LOG2)
   (simplify
(pows REAL_CST@0 @1)
-(if (real_compare (GT_EXPR, TREE_REAL_CST_PTR (@0), )
-&& real_isfinite (TREE_REAL_CST_PTR (@0)))
- (exps (mult (logs @0) @1)
+   (if (real_compare (GT_EXPR, TREE_REAL_CST_PTR (@0), )
+   && real_isfinite (TREE_REAL_CST_PTR (@0)))
+(with {
+   const REAL_VALUE_TYPE *const value = TREE_REAL_CST_PTR (@0);
+   bool use_exp2 = false;
+   if (targetm.libc_has_function (function_c99_misc)
+  && value->cl == rvc_normal)
+{
+  REAL_VALUE_TYPE frac_rvt = *value;
+  SET_REAL_EXP (_rvt, 1);
+  if (real_equal (_rvt, ))
+use_exp2 = true;
+}
+ }
+ (if (!use_exp2)
+  (exps (mult (logs @0) @1))
+  /* As libmvec doesn't have a vectorized exp2, defer optimizing
+this until after vectorization.  */
+  (if (canonicalize_math_after_vectorization_p ())
+   (exps (mult (logs @0) @1
 
  (for sqrts (SQRT)
   cbrts (CBRT)
--- gcc/generic-match-head.c.jj 2018-01-03 10:19:55.454534005 +0100
+++ gcc/generic-match-head.c2018-02-12 14:13:27.088784495 +0100
@@ -68,3 +68,12 @@ canonicalize_math_p ()
 {
   return true;
 }
+
+/* Return true if math operations that are beneficial only after
+   vectorization should be canonicalized.  */
+
+static inline bool
+canonicalize_math_after_vectorization_p ()
+{
+  return false;
+}
--- gcc/gimple-match-head.c.jj  2018-01-03 10:19:55.931534081 +0100
+++ gcc/gimple-match-head.c 2018-02-12 14:14:17.352781873 +0100
@@ -831,3 +831,12 @@ canonicalize_math_p ()
 {
   return !cfun || (cfun->curr_properties & PROP_gimple_opt_math) == 0;
 }
+
+/* Return true if math operations that are beneficial only after
+   vectorization should be canonicalized.  */
+
+static inline bool
+canonicalize_math_after_vectorization_p ()
+{
+  return !cfun || (cfun->curr_properties & PROP_gimple_lvec) != 0;
+}
--- gcc/omp-simd-clone.h.jj 2018-02-12 18:11:01.843931808 +0100
+++ gcc/omp-simd-clone.h2018-02-12 18:12:13.901948041 +0100
@@ -0,0 +1,26 @@
+/* OMP constructs' SIMD clone supporting code.
+
+   Copyright (C) 2005-2018 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+.  */
+
+#ifndef GCC_OMP_SIMD_CLONE_H
+#define GCC_OMP_SIMD_CLONE_H
+
+extern void expand_simd_clones (struct cgraph_node *);
+
+#endif /* GCC_OMP_SIMD_CLONE_H */
---