[google,4.6] back out change for pr49642 (issue5976073)

Hi,

Google branch only. 

Backout this change due to performance regression. 

Tested with bootstrap.

Thanks,

-Rong

2012-04-03   Rong Xu  <xur@google.com>
        
        Google ref b/6284235.
        Manually remove upstream patch for PR49642 and it's
        test case due to performance regression. 

	* gcc/testsuite/gcc.dg/tree-ssa/pr49642.c: Remove.
        * ipa-split.c (forbidden_dominators): Delete variable.
        (check_forbidden_calls): Delete function.
        (dominated_by_forbidden): Likewise.
        (consider_split): Revert.
        (execute_split_functions): Likewise.


--
This patch is available for review at http://codereview.appspot.com/5976073

OK for google-4_6

Dehao

On Wed, Apr 4, 2012 at 8:36 AM, Rong Xu <xur@google.com> wrote:
> Hi,
>
> Google branch only.
>
> Backout this change due to performance regression.
>
> Tested with bootstrap.
>
> Thanks,
>
> -Rong
>
> 2012-04-03   Rong Xu  <xur@google.com>
>
>        Google ref b/6284235.
>        Manually remove upstream patch for PR49642 and it's
>        test case due to performance regression.
>
>        * gcc/testsuite/gcc.dg/tree-ssa/pr49642.c: Remove.
>        * ipa-split.c (forbidden_dominators): Delete variable.
>        (check_forbidden_calls): Delete function.
>        (dominated_by_forbidden): Likewise.
>        (consider_split): Revert.
>        (execute_split_functions): Likewise.
>
> Index: gcc/testsuite/gcc.dg/tree-ssa/pr49642.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/tree-ssa/pr49642.c     (revision 186124)
> +++ gcc/testsuite/gcc.dg/tree-ssa/pr49642.c     (working copy)
> @@ -1,49 +0,0 @@
> -/* Verify that ipa-split is disabled following __builtin_constant_p.  */
> -
> -/* { dg-do compile } */
> -/* { dg-options "-O2 -fdump-tree-optimized" } */
> -
> -typedef unsigned int u32;
> -typedef unsigned long long u64;
> -
> -static inline __attribute__((always_inline)) __attribute__((const))
> -int __ilog2_u32(u32 n)
> -{
> - int bit;
> - asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
> - return 31 - bit;
> -}
> -
> -
> -static inline __attribute__((always_inline)) __attribute__((const))
> -int __ilog2_u64(u64 n)
> -{
> - int bit;
> - asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
> - return 63 - bit;
> -}
> -
> -
> -
> -static u64 ehca_map_vaddr(void *caddr);
> -
> -struct ehca_shca {
> -        u32 hca_cap_mr_pgsize;
> -};
> -
> -static u64 ehca_get_max_hwpage_size(struct ehca_shca *shca)
> -{
> - return 1UL << ( __builtin_constant_p(shca->hca_cap_mr_pgsize) ? ( (shca->hca_cap_mr_pgsize) < 1 ? ____ilog2_NaN() : (shca->hca_cap_mr_pgsize) & (1ULL << 63) ? 63 : (shca->hca_cap_mr_pgsize) & (1ULL << 62) ? 62 : (shca->hca_cap_mr_pgsize) & (1ULL << 61) ? 61 : (shca->hca_cap_mr_pgsize) & (1ULL << 60) ? 60 : (shca->hca_cap_mr_pgsize) & (1ULL << 59) ? 59 : (shca->hca_cap_mr_pgsize) & (1ULL << 58) ? 58 : (shca->hca_cap_mr_pgsize) & (1ULL << 57) ? 57 : (shca->hca_cap_mr_pgsize) & (1ULL << 56) ? 56 : (shca->hca_cap_mr_pgsize) & (1ULL << 55) ? 55 : (shca->hca_cap_mr_pgsize) & (1ULL << 54) ? 54 : (shca->hca_cap_mr_pgsize) & (1ULL << 53) ? 53 : (shca->hca_cap_mr_pgsize) & (1ULL << 52) ? 52 : (shca->hca_cap_mr_pgsize) & (1ULL << 51) ? 51 : (shca->hca_cap_mr_pgsize) & (1ULL << 50) ? 50 : (shca->hca_cap_mr_pgsize) & (1ULL << 49) ? 49 : (shca->hca_cap_mr_pgsize) & (1ULL << 48) ? 48 : (shca->hca_cap_mr_pgsize) & (1ULL << 47) ? 47 : (shca->hca_cap_mr_pgsize) & (1ULL << 46) ? 46 : (shca->h
>  ca_cap_mr_pgsize) & (1ULL << 45) ? 45 : (shca->hca_cap_mr_pgsize) & (1ULL << 44) ? 44 : (shca->hca_cap_mr_pgsize) & (1ULL << 43) ? 43 : (shca->hca_cap_mr_pgsize) & (1ULL << 42) ? 42 : (shca->hca_cap_mr_pgsize) & (1ULL << 41) ? 41 : (shca->hca_cap_mr_pgsize) & (1ULL << 40) ? 40 : (shca->hca_cap_mr_pgsize) & (1ULL << 39) ? 39 : (shca->hca_cap_mr_pgsize) & (1ULL << 38) ? 38 : (shca->hca_cap_mr_pgsize) & (1ULL << 37) ? 37 : (shca->hca_cap_mr_pgsize) & (1ULL << 36) ? 36 : (shca->hca_cap_mr_pgsize) & (1ULL << 35) ? 35 : (shca->hca_cap_mr_pgsize) & (1ULL << 34) ? 34 : (shca->hca_cap_mr_pgsize) & (1ULL << 33) ? 33 : (shca->hca_cap_mr_pgsize) & (1ULL << 32) ? 32 : (shca->hca_cap_mr_pgsize) & (1ULL << 31) ? 31 : (shca->hca_cap_mr_pgsize) & (1ULL << 30) ? 30 : (shca->hca_cap_mr_pgsize) & (1ULL << 29) ? 29 : (shca->hca_cap_mr_pgsize) & (1ULL << 28) ? 28 : (shca->hca_cap_mr_pgsize) & (1ULL << 27) ? 27 : (shca->hca_cap_mr_pgsize) & (1ULL << 26) ? 26 : (shca->hca_cap_mr_pgsize) & (1ULL <<
>  25) ? 25 : (shca->hca_cap_mr_pgsize) & (1ULL << 24) ? 24 : (shca->hca_cap_mr_pgsize) & (1ULL << 23) ? 23 : (shca->hca_cap_mr_pgsize) & (1ULL << 22) ? 22 : (shca->hca_cap_mr_pgsize) & (1ULL << 21) ? 21 : (shca->hca_cap_mr_pgsize) & (1ULL << 20) ? 20 : (shca->hca_cap_mr_pgsize) & (1ULL << 19) ? 19 : (shca->hca_cap_mr_pgsize) & (1ULL << 18) ? 18 : (shca->hca_cap_mr_pgsize) & (1ULL << 17) ? 17 : (shca->hca_cap_mr_pgsize) & (1ULL << 16) ? 16 : (shca->hca_cap_mr_pgsize) & (1ULL << 15) ? 15 : (shca->hca_cap_mr_pgsize) & (1ULL << 14) ? 14 : (shca->hca_cap_mr_pgsize) & (1ULL << 13) ? 13 : (shca->hca_cap_mr_pgsize) & (1ULL << 12) ? 12 : (shca->hca_cap_mr_pgsize) & (1ULL << 11) ? 11 : (shca->hca_cap_mr_pgsize) & (1ULL << 10) ? 10 : (shca->hca_cap_mr_pgsize) & (1ULL << 9) ? 9 : (shca->hca_cap_mr_pgsize) & (1ULL << 8) ? 8 : (shca->hca_cap_mr_pgsize) & (1ULL << 7) ? 7 : (shca->hca_cap_mr_pgsize) & (1ULL << 6) ? 6 : (shca->hca_cap_mr_pgsize) & (1ULL << 5) ? 5 : (shca->hca_cap_mr_pgsize) &
>  (1ULL << 4) ? 4 : (shca->hca_cap_mr_pgsize) & (1ULL << 3) ? 3 : (shca->hca_cap_mr_pgsize) & (1ULL << 2) ? 2 : (shca->hca_cap_mr_pgsize) & (1ULL << 1) ? 1 : (shca->hca_cap_mr_pgsize) & (1ULL << 0) ? 0 : ____ilog2_NaN() ) : (sizeof(shca->hca_cap_mr_pgsize) <= 4) ? __ilog2_u32(shca->hca_cap_mr_pgsize) : __ilog2_u64(shca->hca_cap_mr_pgsize) );
> -}
> -
> -int x(struct ehca_shca *shca) {
> -        return ehca_get_max_hwpage_size(shca);
> -}
> -
> -int y(struct ehca_shca *shca)
> -{
> -        return ehca_get_max_hwpage_size(shca);
> -}
> -
> -/* { dg-final { scan-tree-dump-times "____ilog2_NaN" 0 "optimized" } } */
> -/* { dg-final { cleanup-tree-dump "optimized" } } */
> Index: gcc/ipa-split.c
> ===================================================================
> --- gcc/ipa-split.c     (revision 186124)
> +++ gcc/ipa-split.c     (working copy)
> @@ -130,10 +130,6 @@ struct split_point
>
>  struct split_point best_split_point;
>
> -/* Set of basic blocks that are not allowed to dominate a split point.  */
> -
> -static bitmap forbidden_dominators;
> -
>  static tree find_retval (basic_block return_bb);
>
>  /* Callback for walk_stmt_load_store_addr_ops.  If T is non-SSA automatic
> @@ -274,83 +270,6 @@ done:
>   return ok;
>  }
>
> -/* If STMT is a call, check the callee against a list of forbidden
> -   predicate functions.  If a match is found, look for uses of the
> -   call result in condition statements that compare against zero.
> -   For each such use, find the block targeted by the condition
> -   statement for the nonzero result, and set the bit for this block
> -   in the forbidden dominators bitmap.  The purpose of this is to avoid
> -   selecting a split point where we are likely to lose the chance
> -   to optimize away an unused function call.  */
> -
> -static void
> -check_forbidden_calls (gimple stmt)
> -{
> -  imm_use_iterator use_iter;
> -  use_operand_p use_p;
> -  tree lhs;
> -
> -  /* At the moment, __builtin_constant_p is the only forbidden
> -     predicate function call (see PR49642).  */
> -  if (!gimple_call_builtin_p (stmt, BUILT_IN_CONSTANT_P))
> -    return;
> -
> -  lhs = gimple_call_lhs (stmt);
> -
> -  if (!lhs || TREE_CODE (lhs) != SSA_NAME)
> -    return;
> -
> -  FOR_EACH_IMM_USE_FAST (use_p, use_iter, lhs)
> -    {
> -      tree op1;
> -      basic_block use_bb, forbidden_bb;
> -      enum tree_code code;
> -      edge true_edge, false_edge;
> -      gimple use_stmt = USE_STMT (use_p);
> -
> -      if (gimple_code (use_stmt) != GIMPLE_COND)
> -       continue;
> -
> -      /* Assuming canonical form for GIMPLE_COND here, with constant
> -        in second position.  */
> -      op1 = gimple_cond_rhs (use_stmt);
> -      code = gimple_cond_code (use_stmt);
> -      use_bb = gimple_bb (use_stmt);
> -
> -      extract_true_false_edges_from_block (use_bb, &true_edge, &false_edge);
> -
> -      /* We're only interested in comparisons that distinguish
> -        unambiguously from zero.  */
> -      if (!integer_zerop (op1) || code == LE_EXPR || code == GE_EXPR)
> -       continue;
> -
> -      if (code == EQ_EXPR)
> -       forbidden_bb = false_edge->dest;
> -      else
> -       forbidden_bb = true_edge->dest;
> -
> -      bitmap_set_bit (forbidden_dominators, forbidden_bb->index);
> -    }
> -}
> -
> -/* If BB is dominated by any block in the forbidden dominators set,
> -   return TRUE; else FALSE.  */
> -
> -static bool
> -dominated_by_forbidden (basic_block bb)
> -{
> -  unsigned dom_bb;
> -  bitmap_iterator bi;
> -
> -  EXECUTE_IF_SET_IN_BITMAP (forbidden_dominators, 1, dom_bb, bi)
> -    {
> -      if (dominated_by_p (CDI_DOMINATORS, bb, BASIC_BLOCK (dom_bb)))
> -       return true;
> -    }
> -
> -  return false;
> -}
> -
>  /* We found an split_point CURRENT.  NON_SSA_VARS is bitmap of all non ssa
>    variables used and RETURN_BB is return basic block.
>    See if we can split function here.  */
> @@ -492,18 +411,6 @@ consider_split (struct split_point *current, bitma
>                 "  Refused: split part has non-ssa uses\n");
>       return;
>     }
> -
> -  /* If the split point is dominated by a forbidden block, reject
> -     the split.  */
> -  if (!bitmap_empty_p (forbidden_dominators)
> -      && dominated_by_forbidden (current->entry_bb))
> -    {
> -      if (dump_file && (dump_flags & TDF_DETAILS))
> -       fprintf (dump_file,
> -                "  Refused: split point dominated by forbidden block\n");
> -      return;
> -    }
> -
>   /* See if retval used by return bb is computed by header or split part.
>      When it is computed by split part, we need to produce return statement
>      in the split part and add code to header to pass it around.
> @@ -1422,10 +1329,6 @@ execute_split_functions (void)
>       return 0;
>     }
>
> -  /* Initialize bitmap to track forbidden calls.  */
> -  forbidden_dominators = BITMAP_ALLOC (NULL);
> -  calculate_dominance_info (CDI_DOMINATORS);
> -
>   /* Compute local info about basic blocks and determine function size/time.  */
>   VEC_safe_grow_cleared (bb_info, heap, bb_info_vec, last_basic_block + 1);
>   memset (&best_split_point, 0, sizeof (best_split_point));
> @@ -1447,7 +1350,6 @@ execute_split_functions (void)
>          this_time = estimate_num_insns (stmt, &eni_time_weights) * freq;
>          size += this_size;
>          time += this_time;
> -         check_forbidden_calls (stmt);
>
>          if (dump_file && (dump_flags & TDF_DETAILS))
>            {
> @@ -1469,7 +1371,6 @@ execute_split_functions (void)
>       BITMAP_FREE (best_split_point.split_bbs);
>       todo = TODO_update_ssa | TODO_cleanup_cfg;
>     }
> -  BITMAP_FREE (forbidden_dominators);
>   VEC_free (bb_info, heap, bb_info_vec);
>   bb_info_vec = NULL;
>   return todo;
>
> --
> This patch is available for review at http://codereview.appspot.com/5976073