forked from OSchip/llvm-project
df8e140349
This patch removes the heuristic in
- Polly :: lib/Support/ScopHelper.cpp
The heuristic forces blocks that directly follow a loop header to not to be considered error blocks.
It was introduced in r249611 with the following commit message:
> This replaces the support for user defined error functions by a
> heuristic that tries to determine if a call to a non-pure function
> should be considered "an error". If so the block is assumed not to be
> executed at runtime. While treating all non-pure function calls as
> errors will allow a lot more regions to be analyzed, it will also
> cause us to dismiss a lot again due to an infeasible runtime context.
> This patch tries to limit that effect. A non-pure function call is
> considered an error if it is executed only in conditionally with
> regards to a cheap but simple heuristic.
In the code below `CCK_Abort2()` would be considered as an error block, but not `CCK_Abort1()` due to this heuristic.
```
for (int i = 0; i < n; i+=1) {
if (ErrorCondition1)
CCK_Abort1(); // No __attribute__((noreturn))
if (ErrorCondition2)
CCK_Abort2(); // No __attribute__((noreturn))
}
```
This does not seem useful. Checking error conditions in the beginning of some work is quite common. It causes a switch default-case to be not considered an error block in SPEC's cactuBSSN. The comment justifying the heuristic mentions a "load", which does not seem to be applicable here. It has been proposed to remove the heuristic.
In addition, the patch fixes the following test cases:
- Polly :: ScopDetect/mod_ref_read_pointer.ll
- Polly :: ScopInfo/max-loop-depth.ll
- Polly :: ScopInfo/mod_ref_access_pointee_arguments.ll
- Polly :: ScopInfo/mod_ref_read_pointee_arguments.ll
- Polly :: ScopInfo/mod_ref_read_pointer.ll
- Polly :: ScopInfo/mod_ref_read_pointers.ll
The test cases failed after removing the heuristic.
Differential Revision: https://reviews.llvm.org/D45274
Contributed-by: Lorenzo Chelini <l.chelini@icloud.com>
llvm-svn: 329548
|
||
|---|---|---|
| .. | ||
| aliasing_parametric_simple_1.ll | ||
| aliasing_parametric_simple_2.ll | ||
| aliasing_simple_1.ll | ||
| aliasing_simple_2.ll | ||
| base_pointer.ll | ||
| base_pointer_is_inst_inside_invariant_1___%for.i---%exit.jscop | ||
| base_pointer_load_is_inst_inside_invariant_1___%for.i---%exit.jscop | ||
| base_pointer_load_setNewAccessRelation.ll | ||
| base_pointer_setNewAccessRelation.ll | ||
| cross_loop_non_single_exit.ll | ||
| cross_loop_non_single_exit_2.ll | ||
| dependency_to_phi_node_outside_of_region.ll | ||
| dot-scops.ll | ||
| error-block-always-executed.ll | ||
| error-block-referenced-from-scop.ll | ||
| error-block-unreachable.ll | ||
| expand-region-correctly-2.ll | ||
| expand-region-correctly.ll | ||
| ignore_func_flag_regex.ll | ||
| index_from_unpredictable_loop.ll | ||
| index_from_unpredictable_loop2.ll | ||
| indvars.ll | ||
| intrinsics_1.ll | ||
| intrinsics_2.ll | ||
| intrinsics_3.ll | ||
| invalid-latch-conditions.ll | ||
| invalidate_scalar_evolution.ll | ||
| invariant-load-before-scop.ll | ||
| keep_going_expansion.ll | ||
| mod_ref_read_pointer.ll | ||
| more-than-one-loop.ll | ||
| multidim-with-undef-size.ll | ||
| multidim.ll | ||
| multidim_indirect_access.ll | ||
| multidim_two_accesses_different_delinearization.ll | ||
| nested_loop_single_exit.ll | ||
| non-affine-conditional.ll | ||
| non-affine-float-compare.ll | ||
| non-affine-loop-condition-dependent-access.ll | ||
| non-affine-loop-condition-dependent-access_2.ll | ||
| non-affine-loop-condition-dependent-access_3.ll | ||
| non-affine-loop.ll | ||
| non-beneficial-loops-small-trip-count.ll | ||
| non-constant-add-rec-start-expr.ll | ||
| non-simple-memory-accesses.ll | ||
| non_affine_loop_condition.ll | ||
| only-one-affine-loop.ll | ||
| only_func_flag.ll | ||
| only_func_flag_regex.ll | ||
| parametric-multiply-in-scev-2.ll | ||
| parametric-multiply-in-scev.ll | ||
| phi_with_multi_exiting_edges.ll | ||
| profitability-large-basic-blocks.ll | ||
| profitability-two-nested-loops.ll | ||
| remove_all_children.ll | ||
| report-scop-location.ll | ||
| restrict-undef-size-scopdetect.ll | ||
| run_time_alias_check.ll | ||
| scev_remove_max.ll | ||
| sequential_loops.ll | ||
| simple_loop.ll | ||
| simple_loop_non_single_entry.ll | ||
| simple_loop_non_single_exit.ll | ||
| simple_loop_non_single_exit_2.ll | ||
| simple_loop_two_phi_nodes.ll | ||
| simple_loop_with_param.ll | ||
| simple_loop_with_param_2.ll | ||
| simple_non_single_entry.ll | ||
| skip_function_attribute.ll | ||
| srem_with_parametric_divisor.ll | ||
| statistics.ll | ||
| switch-in-loop-patch.ll | ||
| tlr_is_hoistable_load.ll | ||