[polly] 283feb4 - [polly] Make reduction detection checks more robust - part 2 (#80721)

[via llvm-commits]

Author: Karthika Devi C
Date: 2024-02-12T13:49:32-08:00
New Revision: 283feb42ee509cc56fb75316b4fd86b53a714cf4

URL: https://github.com/llvm/llvm-project/commit/283feb42ee509cc56fb75316b4fd86b53a714cf4
DIFF: https://github.com/llvm/llvm-project/commit/283feb42ee509cc56fb75316b4fd86b53a714cf4.diff

LOG: [polly] Make reduction detection checks more robust - part 2 (#80721)

Existing reduction detection algorithm does two types of memory checks
before marking a load store pair as reduction.
Second check is to verify there is no other memory access in ScopStmt
overlapping with the memory of load and store that forms the reduction.
Existing check misses cases where there could be probable overlap such
as
	A[V] += A[P];
In the above case there is chance of overlap between A[V] and A[P] which
is missed.
This commit addresses this by removing the parameter from space before
checking for compatible space.

Part 1 of this patch :
[75297](https://github.com/llvm/llvm-project/pull/75297)

Added: 
    

Modified: 
    polly/lib/Analysis/ScopBuilder.cpp
    polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_2.ll
    polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_3.ll
    polly/test/ScopInfo/int2ptr_ptr2int.ll

Removed: 
    


################################################################################
diff  --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index 4486164ce0e2a2..0edc41d106415c 100644
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -2516,15 +2516,19 @@ bool hasIntersectingAccesses(isl::set AllAccs, MemoryAccess *LoadMA,
                              MemoryAccess *StoreMA, isl::set Domain,
                              SmallVector<MemoryAccess *, 8> &MemAccs) {
   bool HasIntersectingAccs = false;
+  auto AllAccsNoParams = AllAccs.project_out_all_params();
+
   for (MemoryAccess *MA : MemAccs) {
     if (MA == LoadMA || MA == StoreMA)
       continue;
+    auto AccRel = MA->getAccessRelation().intersect_domain(Domain);
+    auto Accs = AccRel.range();
+    auto AccsNoParams = Accs.project_out_all_params();
 
-    isl::map AccRel = MA->getAccessRelation().intersect_domain(Domain);
-    isl::set Accs = AccRel.range();
+    bool CompatibleSpace = AllAccsNoParams.has_equal_space(AccsNoParams);
 
-    if (AllAccs.has_equal_space(Accs)) {
-      isl::set OverlapAccs = Accs.intersect(AllAccs);
+    if (CompatibleSpace) {
+      auto OverlapAccs = Accs.intersect(AllAccs);
       bool DoesIntersect = !OverlapAccs.is_empty();
       HasIntersectingAccs |= DoesIntersect;
     }

diff  --git a/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_2.ll b/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_2.ll
index f2574b77d6e5ee..e39569abc52da5 100644
--- a/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_2.ll
+++ b/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_2.ll
@@ -44,9 +44,9 @@
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_1] };
 ; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_2] };
-; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: +] [Scalar: 0]
+; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_0 + i0] };
-; INNERMOST-NEXT:         MustWriteAccess :=    [Reduction Type: +] [Scalar: 0]
+; INNERMOST-NEXT:         MustWriteAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_0 + i0] };
 ; INNERMOST-NEXT:     Stmt_bb26
 ; INNERMOST-NEXT:         Domain :=

diff  --git a/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_3.ll b/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_3.ll
index 463db235960800..75dd7ac26bb3ef 100644
--- a/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_3.ll
+++ b/polly/test/ScopInfo/NonAffine/non-affine-loop-condition-dependent-access_3.ll
@@ -44,9 +44,9 @@
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_1] };
 ; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[p_2] };
-; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: +] [Scalar: 0]
+; INNERMOST-NEXT:         ReadAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[i0] };
-; INNERMOST-NEXT:         MustWriteAccess :=    [Reduction Type: +] [Scalar: 0]
+; INNERMOST-NEXT:         MustWriteAccess :=    [Reduction Type: NONE] [Scalar: 0]
 ; INNERMOST-NEXT:             [p_0, p_1, p_2] -> { Stmt_bb16[i0] -> MemRef_A[i0] };
 ; INNERMOST-NEXT:     Stmt_bb26
 ; INNERMOST-NEXT:         Domain :=

diff  --git a/polly/test/ScopInfo/int2ptr_ptr2int.ll b/polly/test/ScopInfo/int2ptr_ptr2int.ll
index 2e7bfbe5eaee3f..9fadc5a8eb2896 100644
--- a/polly/test/ScopInfo/int2ptr_ptr2int.ll
+++ b/polly/test/ScopInfo/int2ptr_ptr2int.ll
@@ -11,9 +11,9 @@
 ;
 ; CHECK:        ReadAccess :=	[Reduction Type: NONE] [Scalar: 0]
 ; CHECK-NEXT:       [val, ptr] -> { Stmt_for_body[i0] -> MemRef_A[9 + val] };
-; CHECK-NEXT:   ReadAccess :=	[Reduction Type: +] [Scalar: 0]
+; CHECK-NEXT:   ReadAccess :=	[Reduction Type: NONE] [Scalar: 0]
 ; CHECK-NEXT:       [val, ptr] -> { Stmt_for_body[i0] -> MemRef_A[9 + ptr] };
-; CHECK-NEXT:   MustWriteAccess :=	[Reduction Type: +] [Scalar: 0]
+; CHECK-NEXT:   MustWriteAccess :=	[Reduction Type: NONE] [Scalar: 0]
 ; CHECK-NEXT:       [val, ptr] -> { Stmt_for_body[i0] -> MemRef_A[9 + ptr] };
 ;
 ; IR:      entry: