Thanks, attached is the updated patch.
Dehao
Index: gcc/testsuite/gcc.dg/predict-3.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-3.c (revision 185903)
+++ gcc/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: gcc/testsuite/gcc.dg/predict-4.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-4.c (revision 185903)
+++ gcc/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: gcc/testsuite/gcc.dg/predict-1.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-1.c (revision 185903)
+++ gcc/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: gcc/testsuite/gcc.dg/predict-5.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-5.c (revision 0)
+++ gcc/testsuite/gcc.dg/predict-5.c (revision 0)
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
+
+extern int global;
+
+int bar (int);
+
+void foo (int base, int bound)
+{
+ int i, ret = 0;
+ for (i = base; i <= bound; i++)
+ {
+ if (i > base)
+ global += bar (i);
+ if (i > base + 1)
+ global += bar (i);
+ if (i >= base + 3)
+ global += bar (i);
+ if (i - 2 >= base)
+ global += bar (i);
+ }
+}
+
+/* { dg-final { scan-tree-dump-times "loop iv compare heuristics:
100.0%" 4 "profile_estimate"} } */
+/* { dg-final { cleanup-tree-dump "profile_estimate" } } */
Index: gcc/testsuite/gcc.dg/predict-2.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-2.c (revision 185903)
+++ gcc/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: gcc/testsuite/gcc.dg/predict-6.c
===================================================================
--- gcc/testsuite/gcc.dg/predict-6.c (revision 0)
+++ gcc/testsuite/gcc.dg/predict-6.c (revision 0)
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
+
+extern int global;
+
+int bar (int);
+
+void foo (int base, int bound)
+{
+ int i, ret = 0;
+ for (i = base; i <= bound; i++)
+ {
+ if (i < base)
+ global += bar (i);
+ if (i < base + 1)
+ global += bar (i);
+ if (i <= base + 3)
+ global += bar (i);
+ if (i - 1 < base)
+ global += bar (i);
+ }
+}
+
+/* { dg-final { scan-tree-dump-times "loop iv compare heuristics:
0.0%" 4 "profile_estimate"} } */
+/* { dg-final { cleanup-tree-dump "profile_estimate" } } */
Index: gcc/predict.c
===================================================================
--- gcc/predict.c (revision 185903)
+++ gcc/predict.c (working copy)
@@ -1070,6 +1070,8 @@
bound = get_base_value (bound);
if (!bound)
return false;
+ if (TREE_CODE (base) != INTEGER_CST)
+ base = get_base_value (base);
*loop_invariant = bound;
*compare_code = code;
@@ -1185,8 +1187,7 @@
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 +1231,52 @@
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. */
On Thu, Mar 29, 2012 at 8:06 AM, Xinliang David Li <[email protected]> wrote:
> Can the test case be improved so that expected prediction results is
> checked (with the help of more dumping such as blah blah is predicted
> to be taken/not taken with probability xyz) ?
>
> Also the more test cases need to be added to cover more cases >base, >
> base +1, >=base +2, < base+1, <=base+1 etc -- even though expression
> reassociation will normalize them ...
>
> Thanks,
>
> David
>
> On Wed, Mar 28, 2012 at 4:54 PM, Dehao Chen <[email protected]> wrote:
>> Hi,
>>
>> This patch handles the comparison of iv against the loop iv initial
>> value. Previously, we only handle the comparison of iv against its
>> bound.
>>
>> Bootstrapped and passed all regression tests.
>>
>> Ok for google branches?
>>
>> Thanks,
>> Dehao
>>
>> 2012-03-29 Dehao Chen <[email protected]>
>>
>> * predict.c (predict_iv_comparison): Add the comparison of induction
>> variable against its initial value.
>>
>> 2012-03-29 Dehao Chen <[email protected]>
>>
>> * gcc.dg/predict-5.c: Check if LOOP_IV_COMPARE static predict
>> heuristic is working properly.
>>
>> Index: gcc/testsuite/gcc.dg/predict-5.c
>> ===================================================================
>> --- gcc/testsuite/gcc.dg/predict-5.c (revision 0)
>> +++ gcc/testsuite/gcc.dg/predict-5.c (revision 0)
>> @@ -0,0 +1,21 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-O2 -fdump-tree-profile_estimate" } */
>> +
>> +extern int global;
>> +
>> +int bar(int);
>> +
>> +void foo (int base, int bound)
>> +{
>> + int i, ret = 0;
>> + for (i = base; i <= bound; i++)
>> + {
>> + if (i > base + 2)
>> + global += bar (i);
>> + else
>> + global += bar (i + 1);
>> + }
>> +}
>> +
>> +/* { dg-final { scan-tree-dump "loop iv compare heuristics"
>> "profile_estimate"} } */
>> +/* { dg-final { cleanup-tree-dump "profile_estimate" } } */
>> Index: gcc/predict.c
>> ===================================================================
>> --- gcc/predict.c (revision 185903)
>> +++ gcc/predict.c (working copy)
>> @@ -1185,8 +1185,7 @@
>> return;
>> }
>>
>> - if (!expr_coherent_p (loop_bound_var, compare_var)
>> - || loop_iv_base_var != compare_base)
>> + if (loop_iv_base_var != compare_base)
>> return;
>>
>> /* If loop bound, base and compare bound are all constents, we can
>> @@ -1230,34 +1229,52 @@
>> 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. */
