[Polly] Use assumed context during ast generation

[Meinersbur]

Summary missing?

Could you explain why this changes anything, because the scheduler should produce a schedule withing the assumed context only. (i.e. because we gist the assumed context before scheduling if I am not mistaken)

Does this change the output other than adding conditionals? I guess these are irrelevant because they are checked beforehand for loop versioning anyway. Do the additional conditions affect execution time?

[jdoerfert]

Meinersbur added a comment.

Summary missing?

Could you explain why this changes anything, because the scheduler
should produce a schedule withing the assumed context only. (i.e.
because we gist the assumed context before scheduling if I am not
mistaken)

It does not. There is no assumed context involved in scheduling.

Does this change the output other than adding conditionals? I guess
these are irrelevant because they are checked beforehand for loop
versioning anyway. Do the additional conditions affect execution time?

This removes dead statements from the schedule and hence the AST.

• signature.asc219 BDownload

lib/CodeGen/IslAst.cpp

 #include "llvm/Analysis/RegionInfo.h"
 #include "llvm/Support/Debug.h"
 #include "isl/aff.h"
 #include "isl/ast_build.h"
 #include "isl/list.h"
 #include "isl/map.h"
 #include "isl/set.h"
 #include "isl/union_map.h"
+#include "isl/union_set.h"
 
 #define DEBUG_TYPE "polly-ast"
 
 using namespace llvm;
 using namespace polly;
 
 using IslAstUserPayload = IslAstInfo::IslAstUserPayload;
 
if (PerformParallelTest) {
     Build = isl_ast_build_set_before_each_for(Build, &astBuildBeforeFor,
                                               &BuildInfo);
     Build =
         isl_ast_build_set_after_each_for(Build, &astBuildAfterFor, &BuildInfo);
   }
 
   buildRunCondition(Build);
 
-  Root = isl_ast_build_node_from_schedule(Build, S->getScheduleTree());
+  isl_schedule *Schedule = S->getScheduleTree();
+  Schedule = isl_schedule_intersect_domain(
+      Schedule, isl_union_set_from_set(S->getAssumedContext()));
+  Schedule = isl_schedule_gist_domain_params(Schedule, S->getAssumedContext());
+  Root = isl_ast_build_node_from_schedule(Build, Schedule);
 
   isl_ast_build_free(Build);
 }
 
 IslAst *IslAst::create(Scop *Scop, const Dependences &D) {
   auto Ast = new IslAst(Scop);
   Ast->init(D);
   return Ast;

test/Isl/Ast/simple-run-time-condition.ll

 ; cause any code to be executed are not generated.
 
 ; CHECK: if (
 ; CHECK: (o >= 1 && n + p <= 9223372036854775808 && q <= 0 && m + q >= 0)
 ; CHECK: ||
 ; CHECK; (o <= 0 && m + q >= 100 && q <= 100)
 ; CHECK: )
 
-; CHECK:     if (o <= 0) {
+; CHECK:     if (o <= 0 && m + q >= 100) {
 ; CHECK:       for (int c0 = 0; c0 < n; c0 += 1)
 ; CHECK:         for (int c1 = 0; c1 < m; c1 += 1)
 ; CHECK:           Stmt_for_j_1(c0, c1);
 ; CHECK:     } else
 ; CHECK:       for (int c0 = 0; c0 < n; c0 += 1)
 ; CHECK:         for (int c1 = 0; c1 < m; c1 += 1)
 ; CHECK:           Stmt_for_j(c0, c1);