ok. Is the change in google-47 branch?
Please also submit this to trunk (there was also a previous one pending).
thanks,
David
On Thu, May 3, 2012 at 4:44 AM, Dehao Chen <de...@google.com> wrote:
> Hi,
>
> This patch was reverted because of performance degradation. However, it
> turns out to be an innocent performance loss. Thus we want to reenable it in
> google branches.
>
> Passed bootstrap and gcc regression tests and google performance tests.
>
> OK for google branch?
>
> Thanks,
> Dehao
>
> gcc/ChangeLog.google-4_6
> 2012-05-03 Dehao Chen <de...@google.com>
>
> * predict.c (predict_iv_comparison): Add the comparison of induction
> variable against its initial value. (Reenable r185948)
>
> gcc/testsuite/ChangeLog.google-4_6
> 2012-05-03 Dehao Chen <de...@google.com>
>
> * gcc.dg/predict-1.c: Check if LOOP_IV_COMPARE static predict
> heuristic is working properly. Reenable r185948.
> * gcc.dg/predict-2.c: Likewise
> * gcc.dg/predict-3.c: Likewise
> * gcc.dg/predict-4.c: Likewise
> * gcc.dg/predict-5.c: Likewise
> * gcc.dg/predict-6.c: Likewise
>
> Index: testsuite/gcc.dg/predict-3.c
> ===================================================================
> --- testsuite/gcc.dg/predict-3.c (revision 187013)
> +++ testsuite/gcc.dg/predict-3.c (working copy)
> @@ -10,10 +10,16 @@
> int i, ret = 0;
> for (i = 0; i <= bound; i++)
> {
> + if (i < bound - 2)
> + global += bar (i);
> + if (i <= bound)
> + global += bar (i);
> + if (i + 1 < bound)
> + global += bar (i);
> if (i != bound)
> global += bar (i);
> }
> }
>
> -/* { dg-final { scan-tree-dump "loop iv compare heuristics"
> "profile_estimate"} } */
> +/* { dg-final { scan-tree-dump-times "loop iv compare heuristics: 100.0%" 4
> "profile_estimate"} } */
> /* { dg-final { cleanup-tree-dump "profile_estimate" } } */
> Index: testsuite/gcc.dg/predict-4.c
> ===================================================================
> --- testsuite/gcc.dg/predict-4.c (revision 187013)
> +++ testsuite/gcc.dg/predict-4.c (working copy)
> @@ -15,5 +15,5 @@
> }
> }
>
> -/* { dg-final { scan-tree-dump "loop iv compare heuristics"
> "profile_estimate"} } */
> +/* { dg-final { scan-tree-dump "loop iv compare heuristics: 50.0%"
> "profile_estimate"} } */
> /* { dg-final { cleanup-tree-dump "profile_estimate" } } */
> Index: testsuite/gcc.dg/predict-1.c
> ===================================================================
> --- testsuite/gcc.dg/predict-1.c (revision 187013)
> +++ testsuite/gcc.dg/predict-1.c (working copy)
> @@ -10,10 +10,18 @@
> int i, ret = 0;
> for (i = 0; i < bound; i++)
> {
> + if (i > bound)
> + global += bar (i);
> + if (i >= bound + 2)
> + global += bar (i);
> if (i > bound - 2)
> global += bar (i);
> + if (i + 2 > bound)
> + global += bar (i);
> + if (i == 10)
> + global += bar (i);
> }
> }
>
> -/* { dg-final { scan-tree-dump "loop iv compare heuristics"
> "profile_estimate"} } */
> +/* { dg-final { scan-tree-dump-times "loop iv compare heuristics: 0.0%" 5
> "profile_estimate"} } */
> /* { dg-final { cleanup-tree-dump "profile_estimate" } } */
> Index: testsuite/gcc.dg/predict-2.c
> ===================================================================
> --- testsuite/gcc.dg/predict-2.c (revision 187013)
> +++ testsuite/gcc.dg/predict-2.c (working copy)
> @@ -5,12 +5,20 @@
>
> int bar(int);
>
> -void foo (int bound)
> +void foo (int base, int bound)
> {
> int i, ret = 0;
> - for (i = 0; i < bound; i++)
> + for (i = base; i < bound; i++)
> {
> - if (i > bound * bound )
> + if (i > bound * bound)
> + global += bar (i);
> + if (i > bound + 10)
> + global += bar (i);
> + if (i <= bound + 10)
> + global += bar (i);
> + if (i > base + 10)
> + global += bar (i);
> + if (i < base - 10)
> global += bar (i);
> }
> }
> Index: predict.c
> ===================================================================
> --- predict.c (revision 187013)
> +++ predict.c (working copy)
> @@ -1070,6 +1070,10 @@
> bound = get_base_value (bound);
> if (!bound)
> return false;
> + if (TREE_CODE (base) != INTEGER_CST)
> + base = get_base_value (base);
> + if (!base)
> + return false;
>
> *loop_invariant = bound;
> *compare_code = code;
> @@ -1185,8 +1189,7 @@
> return;
> }
>
> - if (!expr_coherent_p (loop_bound_var, compare_var)
> - || loop_iv_base_var != compare_base)
> + if (!expr_coherent_p(loop_iv_base_var, compare_base))
> return;
>
> /* If loop bound, base and compare bound are all constents, we can
> @@ -1230,34 +1233,52 @@
> return;
> }
>
> - if ((loop_bound_code == LT_EXPR || loop_bound_code == LE_EXPR)
> - && (compare_code == LT_EXPR || compare_code == LE_EXPR))
> - predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> - else if ((loop_bound_code == GT_EXPR || loop_bound_code == GE_EXPR)
> - && (compare_code == GT_EXPR || compare_code == GE_EXPR))
> - predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> - else if (loop_bound_code == NE_EXPR)
> - {
> - /* If the loop backedge condition is "(i != bound)", we do
> - the comparison based on the step of IV:
> - * step < 0 : backedge condition is like (i > bound)
> - * step > 0 : backedge condition is like (i < bound) */
> - gcc_assert (loop_bound_step != 0);
> + if (expr_coherent_p (loop_bound_var, compare_var))
> + {
> + if ((loop_bound_code == LT_EXPR || loop_bound_code == LE_EXPR)
> + && (compare_code == LT_EXPR || compare_code == LE_EXPR))
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> + else if ((loop_bound_code == GT_EXPR || loop_bound_code == GE_EXPR)
> + && (compare_code == GT_EXPR || compare_code == GE_EXPR))
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> + else if (loop_bound_code == NE_EXPR)
> + {
> + /* If the loop backedge condition is "(i != bound)", we do
> + the comparison based on the step of IV:
> + * step < 0 : backedge condition is like (i > bound)
> + * step > 0 : backedge condition is like (i < bound) */
> + gcc_assert (loop_bound_step != 0);
> + if (loop_bound_step > 0
> + && (compare_code == LT_EXPR
> + || compare_code == LE_EXPR))
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> + else if (loop_bound_step < 0
> + && (compare_code == GT_EXPR
> + || compare_code == GE_EXPR))
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> + else
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, NOT_TAKEN);
> + }
> + else
> + /* The branch is predicted not-taken if loop_bound_code is
> + opposite with compare_code. */
> + predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, NOT_TAKEN);
> + }
> + else if (expr_coherent_p (loop_iv_base_var, compare_var))
> + {
> + /* For cases like:
> + for (i = s; i < h; i++)
> + if (i > s + 2) ....
> + The branch should be predicted taken. */
> if (loop_bound_step > 0
> - && (compare_code == LT_EXPR
> - || compare_code == LE_EXPR))
> + && (compare_code == GT_EXPR || compare_code == GE_EXPR))
> predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> else if (loop_bound_step < 0
> - && (compare_code == GT_EXPR
> - || compare_code == GE_EXPR))
> + && (compare_code == LT_EXPR || compare_code == LE_EXPR))
> predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, TAKEN);
> else
> predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, NOT_TAKEN);
> }
> - else
> - /* The branch is predicted not-taken if loop_bound_code is
> - opposite with compare_code. */
> - predict_edge_def (then_edge, PRED_LOOP_IV_COMPARE, NOT_TAKEN);
> }
>
> /* Predict edge probabilities by exploiting loop structure. */
>
