Re: [PATCH] Improve unroller size estimate

[Richard Biener]

On Tue, Feb 14, 2017 at 3:53 PM, Richard Biener  wrote:
>
> The following patch improves the constant_after_peeling estimate of
> the GIMPLE unroller by not requiring a strictly "simple-iv" but
> an evolution w/o symbols.  It also avoids computing any of this for
> ops defined in a subloop of the loop we unroll (that only yields
> garbage).  So it makes constant_after_peeling cheaper as well.
>
> It also adjusts the simple-minded CCP to propagate all constants
> (esp. float and vector constants).
>
> Bootstrapped on x86_64-unknown-linux-gnu, testing in progress, queued for
> GCC 8.

Re-bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

> Richard.
>
> 2016-02-14  Richard Biener  
>
> * tree-ssa-loop-ivcanon.c (constant_after_peeling): Do not require
> sth as strict as a simple_iv but a chrec without symbols and an
> operand defined in the loop we are peeling (and not some subloop).
> (propagate_constants_for_unrolling): Propagate all constants.
>
> * gcc.dg/vect/no-scevccp-outer-13.c: Adjust to prevent unrolling
> of inner loops.
> * gcc.dg/vect/no-scevccp-outer-7.c: Likewise.
> * gcc.dg/vect/vect-104.c: Likewise.
>
> Index: gcc/tree-ssa-loop-ivcanon.c
> ===
> --- gcc/tree-ssa-loop-ivcanon.c (revision 245417)
> +++ gcc/tree-ssa-loop-ivcanon.c (working copy)
> @@ -157,8 +157,6 @@ struct loop_size
>  static bool
>  constant_after_peeling (tree op, gimple *stmt, struct loop *loop)
>  {
> -  affine_iv iv;
> -
>if (is_gimple_min_invariant (op))
>  return true;
>
> @@ -188,12 +186,12 @@ constant_after_peeling (tree op, gimple
>return false;
>  }
>
> -  /* Induction variables are constants.  */
> -  if (!simple_iv (loop, loop_containing_stmt (stmt), op, , false))
> -return false;
> -  if (!is_gimple_min_invariant (iv.base))
> +  /* Induction variables are constants when defined in loop.  */
> +  if (loop_containing_stmt (stmt) != loop)
>  return false;
> -  if (!is_gimple_min_invariant (iv.step))
> +  tree ev = analyze_scalar_evolution (loop, op);
> +  if (chrec_contains_undetermined (ev)
> +  || chrec_contains_symbols (ev))
>  return false;
>return true;
>  }
> @@ -1259,7 +1257,7 @@ propagate_constants_for_unrolling (basic
>
>if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (result)
>   && gimple_phi_num_args (phi) == 1
> - && TREE_CODE (arg) == INTEGER_CST)
> + && CONSTANT_CLASS_P (arg))
> {
>   replace_uses_by (result, arg);
>   gsi_remove (, true);
> @@ -1276,7 +1274,7 @@ propagate_constants_for_unrolling (basic
>tree lhs;
>
>if (is_gimple_assign (stmt)
> - && gimple_assign_rhs_code (stmt) == INTEGER_CST
> + && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_constant
>   && (lhs = gimple_assign_lhs (stmt), TREE_CODE (lhs) == SSA_NAME)
>   && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
> {
> Index: gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c
> ===
> --- gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c (revision 245417)
> +++ gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c (working copy)
> @@ -1,4 +1,5 @@
>  /* { dg-require-effective-target vect_int } */
> +/* { dg-additional-options "--param max-completely-peel-times=1" } */
>
>  #include 
>  #include "tree-vect.h"
> Index: gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c
> ===
> --- gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c  (revision 245417)
> +++ gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c  (working copy)
> @@ -1,4 +1,5 @@
>  /* { dg-require-effective-target vect_int } */
> +/* { dg-additional-options "--param max-completely-peel-times=1" } */
>
>  #include 
>  #include "tree-vect.h"
> Index: gcc/testsuite/gcc.dg/vect/vect-104.c
> ===
> --- gcc/testsuite/gcc.dg/vect/vect-104.c(revision 245417)
> +++ gcc/testsuite/gcc.dg/vect/vect-104.c(working copy)
> @@ -1,4 +1,5 @@
>  /* { dg-require-effective-target vect_int } */
> +/* { dg-additional-options "--param max-completely-peel-times=1" } */
>
>  #include 
>  #include 

[PATCH] Improve unroller size estimate

[Richard Biener]

The following patch improves the constant_after_peeling estimate of
the GIMPLE unroller by not requiring a strictly "simple-iv" but
an evolution w/o symbols.  It also avoids computing any of this for
ops defined in a subloop of the loop we unroll (that only yields
garbage).  So it makes constant_after_peeling cheaper as well.

It also adjusts the simple-minded CCP to propagate all constants
(esp. float and vector constants).

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress, queued for 
GCC 8.

Richard.

2016-02-14  Richard Biener  

* tree-ssa-loop-ivcanon.c (constant_after_peeling): Do not require
sth as strict as a simple_iv but a chrec without symbols and an
operand defined in the loop we are peeling (and not some subloop).
(propagate_constants_for_unrolling): Propagate all constants.

* gcc.dg/vect/no-scevccp-outer-13.c: Adjust to prevent unrolling
of inner loops.
* gcc.dg/vect/no-scevccp-outer-7.c: Likewise.
* gcc.dg/vect/vect-104.c: Likewise.

Index: gcc/tree-ssa-loop-ivcanon.c
===
--- gcc/tree-ssa-loop-ivcanon.c (revision 245417)
+++ gcc/tree-ssa-loop-ivcanon.c (working copy)
@@ -157,8 +157,6 @@ struct loop_size
 static bool
 constant_after_peeling (tree op, gimple *stmt, struct loop *loop)
 {
-  affine_iv iv;
-
   if (is_gimple_min_invariant (op))
 return true;
 
@@ -188,12 +186,12 @@ constant_after_peeling (tree op, gimple
   return false;
 }
 
-  /* Induction variables are constants.  */
-  if (!simple_iv (loop, loop_containing_stmt (stmt), op, , false))
-return false;
-  if (!is_gimple_min_invariant (iv.base))
+  /* Induction variables are constants when defined in loop.  */
+  if (loop_containing_stmt (stmt) != loop)
 return false;
-  if (!is_gimple_min_invariant (iv.step))
+  tree ev = analyze_scalar_evolution (loop, op);
+  if (chrec_contains_undetermined (ev)
+  || chrec_contains_symbols (ev))
 return false;
   return true;
 }
@@ -1259,7 +1257,7 @@ propagate_constants_for_unrolling (basic
 
   if (! SSA_NAME_OCCURS_IN_ABNORMAL_PHI (result)
  && gimple_phi_num_args (phi) == 1
- && TREE_CODE (arg) == INTEGER_CST)
+ && CONSTANT_CLASS_P (arg))
{
  replace_uses_by (result, arg);
  gsi_remove (, true);
@@ -1276,7 +1274,7 @@ propagate_constants_for_unrolling (basic
   tree lhs;
 
   if (is_gimple_assign (stmt)
- && gimple_assign_rhs_code (stmt) == INTEGER_CST
+ && TREE_CODE_CLASS (gimple_assign_rhs_code (stmt)) == tcc_constant
  && (lhs = gimple_assign_lhs (stmt), TREE_CODE (lhs) == SSA_NAME)
  && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
{
Index: gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c
===
--- gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c (revision 245417)
+++ gcc/testsuite/gcc.dg/vect/no-scevccp-outer-13.c (working copy)
@@ -1,4 +1,5 @@
 /* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "--param max-completely-peel-times=1" } */
 
 #include 
 #include "tree-vect.h"
Index: gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c
===
--- gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c  (revision 245417)
+++ gcc/testsuite/gcc.dg/vect/no-scevccp-outer-7.c  (working copy)
@@ -1,4 +1,5 @@
 /* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "--param max-completely-peel-times=1" } */
 
 #include 
 #include "tree-vect.h"
Index: gcc/testsuite/gcc.dg/vect/vect-104.c
===
--- gcc/testsuite/gcc.dg/vect/vect-104.c(revision 245417)
+++ gcc/testsuite/gcc.dg/vect/vect-104.c(working copy)
@@ -1,4 +1,5 @@
 /* { dg-require-effective-target vect_int } */
+/* { dg-additional-options "--param max-completely-peel-times=1" } */
 
 #include 
 #include