On Thu, Nov 23, 2017 at 1:16 AM, Jeff Law <l...@redhat.com> wrote:
>
> Clients of the evrp range analysis may not have initialized the SCEV
> infrastructure, and in fact my not want to (DOM for example).
>
> Yet inside both vr-values.c and gimple-ssa-evrp-analyze.c we have calls
> into SCEV (that will fault/abort if SCEV is not properly initialized).
>
> This patch allows clients of vr-values.c and gimple-ssa-evrp-analyze.c
> to indicate if they want SCEV analysis.
>
> Bootstrapped and regression tested by itself as well as with the DOM
> patches to use EVRP analysis (which test the "don't want SCEV path).
>
> OK for the trunk?
There's also scev_initialized_p () which you could conveniently use.
Richard.
>
> Jeff
>
> * gimple-ssa-evrp-analyze.h (class evrp_range_analyzer): New data
> member USE_SCEV.
> * gimple-ssa-evrp-analyze.c
> (evrp_range_analyzer::evrp_range_analyzer): Add new use_scev argument.
> Pass it to the vr_values ctor.
> (evrp_range_analyzer::record_ranges_from_phis): Conditionally use
> SCEV to refine ranges for PHIs.
> * gimple-ssa-evrp (evrp_dom_walker::evrp_dom_walker): Ask for
> SCEV analysis in the vr-values engine.
> * vr-values.h (class vr_values): New data meber USE_SCEV.
> * vr-values.c (vr_values::vr_values): Add new use_scev argument.
> (vr_values::extract_range_from_phi_node): Conditionally use
> SCEV to refine ranges for PHIs.
>
>
> diff --git a/gcc/gimple-ssa-evrp-analyze.c b/gcc/gimple-ssa-evrp-analyze.c
> index 68a2cdc..bc41be1 100644
> --- a/gcc/gimple-ssa-evrp-analyze.c
> +++ b/gcc/gimple-ssa-evrp-analyze.c
> @@ -42,7 +42,8 @@ along with GCC; see the file COPYING3. If not see
> #include "vr-values.h"
> #include "gimple-ssa-evrp-analyze.h"
>
> -evrp_range_analyzer::evrp_range_analyzer () : stack (10)
> +evrp_range_analyzer::evrp_range_analyzer (bool use_scev_)
> + : vr_values (use_scev_), stack (10), use_scev (use_scev_)
> {
> edge e;
> edge_iterator ei;
> @@ -176,7 +177,8 @@ evrp_range_analyzer::record_ranges_from_phis (basic_block
> bb)
> to use VARYING for them. But we can still resort to
> SCEV for loop header PHIs. */
> struct loop *l;
> - if (interesting
> + if (use_scev
> + && interesting
> && (l = loop_containing_stmt (phi))
> && l->header == gimple_bb (phi))
> vr_values.adjust_range_with_scev (&vr_result, l, phi, lhs);
> @@ -341,3 +343,4 @@ evrp_range_analyzer::pop_value_range (tree var)
> stack.pop ();
> return vr;
> }
> +
> diff --git a/gcc/gimple-ssa-evrp-analyze.h b/gcc/gimple-ssa-evrp-analyze.h
> index 3d64c50..18f5b8c 100644
> --- a/gcc/gimple-ssa-evrp-analyze.h
> +++ b/gcc/gimple-ssa-evrp-analyze.h
> @@ -23,7 +23,7 @@ along with GCC; see the file COPYING3. If not see
> class evrp_range_analyzer
> {
> public:
> - evrp_range_analyzer (void);
> + evrp_range_analyzer (bool);
> ~evrp_range_analyzer (void) { stack.release (); }
>
> void enter (basic_block);
> @@ -65,6 +65,9 @@ class evrp_range_analyzer
>
> /* STACK holds the old VR. */
> auto_vec<std::pair <tree, value_range*> > stack;
> +
> + /* Whether or not to use SCEV to refine ranges. */
> + bool use_scev;
> };
>
> #endif /* GCC_GIMPLE_SSA_EVRP_ANALYZE_H */
> diff --git a/gcc/gimple-ssa-evrp.c b/gcc/gimple-ssa-evrp.c
> index f56d67f..13e4e16 100644
> --- a/gcc/gimple-ssa-evrp.c
> +++ b/gcc/gimple-ssa-evrp.c
> @@ -69,6 +69,7 @@ class evrp_dom_walker : public dom_walker
> public:
> evrp_dom_walker ()
> : dom_walker (CDI_DOMINATORS),
> + evrp_range_analyzer (true),
> evrp_folder (evrp_range_analyzer.get_vr_values ())
> {
> need_eh_cleanup = BITMAP_ALLOC (NULL);
> diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
> index 838822d..46be749 100644
> --- a/gcc/tree-vrp.c
> +++ b/gcc/tree-vrp.c
> @@ -4737,6 +4737,7 @@ insert_range_assertions (void)
> class vrp_prop : public ssa_propagation_engine
> {
> public:
> + vrp_prop (bool use_scev_) : vr_values (use_scev_) { }
> enum ssa_prop_result visit_stmt (gimple *, edge *, tree *) FINAL OVERRIDE;
> enum ssa_prop_result visit_phi (gphi *) FINAL OVERRIDE;
>
> @@ -6862,7 +6863,7 @@ execute_vrp (bool warn_array_bounds_p)
> /* For visiting PHI nodes we need EDGE_DFS_BACK computed. */
> mark_dfs_back_edges ();
>
> - class vrp_prop vrp_prop;
> + class vrp_prop vrp_prop (true);
> vrp_prop.vrp_initialize ();
> vrp_prop.ssa_propagate ();
> vrp_prop.vrp_finalize (warn_array_bounds_p);
> diff --git a/gcc/vr-values.c b/gcc/vr-values.c
> index 2d11861..54b0be5 100644
> --- a/gcc/vr-values.c
> +++ b/gcc/vr-values.c
> @@ -1907,7 +1907,8 @@ vr_values::dump_all_value_ranges (FILE *file)
>
> /* Initialize VRP lattice. */
>
> -vr_values::vr_values () : vrp_value_range_pool ("Tree VRP value ranges")
> +vr_values::vr_values (bool use_scev_)
> + : vrp_value_range_pool ("Tree VRP value ranges"), use_scev (use_scev_)
> {
> values_propagated = false;
> num_vr_values = num_ssa_names;
> @@ -2935,7 +2936,8 @@ scev_check:
> scev_check can be reached from two paths, one is a fall through from
> above
> "varying" label, the other is direct goto from code block which tries to
> avoid infinite simulation. */
> - if ((l = loop_containing_stmt (phi))
> + if (use_scev
> + && (l = loop_containing_stmt (phi))
> && l->header == gimple_bb (phi))
> adjust_range_with_scev (vr_result, l, phi, lhs);
>
> diff --git a/gcc/vr-values.h b/gcc/vr-values.h
> index 124ee6f..bfeb1e4 100644
> --- a/gcc/vr-values.h
> +++ b/gcc/vr-values.h
> @@ -37,7 +37,7 @@ along with GCC; see the file COPYING3. If not see
> class vr_values
> {
> public:
> - vr_values (void);
> + vr_values (bool);
> ~vr_values (void);
>
> value_range *get_value_range (const_tree);
> @@ -115,6 +115,9 @@ class vr_values
> /* Allocations for equivalences all come from this obstack. */
> bitmap_obstack vrp_equiv_obstack;
>
> + /* Whether or not to use SCEV to refine ranges. */
> + bool use_scev;
> +
> /* Value range array. After propagation, VR_VALUE[I] holds the range
> of values that SSA name N_I may take. */
> unsigned int num_vr_values;
>
