[llvm] aef6d46 - [LAA] Add test that shows MaxSafeDepDistBytes is incorrect. NFC.

[Michael Maitland via llvm-commits]

Author: Michael Maitland
Date: 2023-07-06T14:37:30-07:00
New Revision: aef6d4610fabf2b4c2f9e2fcfab24fce6f59cc86

URL: https://github.com/llvm/llvm-project/commit/aef6d4610fabf2b4c2f9e2fcfab24fce6f59cc86
DIFF: https://github.com/llvm/llvm-project/commit/aef6d4610fabf2b4c2f9e2fcfab24fce6f59cc86.diff

LOG: [LAA] Add test that shows MaxSafeDepDistBytes is incorrect. NFC.

This precommit patch shows MaxSafeDepBytesDist is 24 when it should
be 8.

Differential Revision: https://reviews.llvm.org/D154173

Added: 
    llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll

Modified: 
    

Removed: 
    


################################################################################
diff  --git a/llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll b/llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll
new file mode 100644
index 00000000000000..946d9b7cfd9b83
--- /dev/null
+++ b/llvm/test/Analysis/LoopAccessAnalysis/max_safe_dep_dist_non_unit_stride.ll
@@ -0,0 +1,52 @@
+; RUN: opt -S -disable-output -passes='print<access-info>' < %s 2>&1 | FileCheck %s
+
+; Generated from following C program:
+; void foo(int len, int *a) {
+;   for (int k = 0; k < len; k+=3) {
+;     a[k] = a[k + 4];
+;     a[k+2] = a[k+6];
+;   }
+; }
+define void @foo(i64  %len, ptr %a) {
+; CHECK-LABEL: Loop access info in function 'foo':
+; CHECK-NEXT:  loop:
+; CHECK-NEXT:    Memory dependences are safe with a maximum dependence distance of 24 bytes
+; CHECK-NEXT:    Dependences:
+; CHECK-NEXT:      BackwardVectorizable:
+; CHECK-NEXT:          store i32 %0, ptr %arrayidx2, align 4 ->
+; CHECK-NEXT:          %1 = load i32, ptr %arrayidx5, align 4
+; CHECK-EMPTY:
+; CHECK-NEXT:    Run-time memory checks:
+; CHECK-NEXT:    Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT:    Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:    SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT:    Expressions re-written:
+;
+loop.preheader:
+  br label %loop
+
+loop.exit:
+  br label %exit
+
+exit:
+  ret void
+
+loop:
+  %iv = phi i64 [ 0, %loop.preheader ], [ %iv.next, %loop ]
+  %iv.4 = add nuw nsw i64 %iv, 4
+  %arrayidx = getelementptr inbounds i32, ptr %a, i64 %iv.4
+  %0 = load i32, ptr %arrayidx, align 4
+  %arrayidx2 = getelementptr inbounds i32, ptr %a, i64 %iv
+  store i32 %0, ptr %arrayidx2, align 4
+  %iv.6 = add nuw nsw i64 %iv, 6
+  %arrayidx5 = getelementptr inbounds i32, ptr %a, i64 %iv.6
+  %1 = load i32, ptr %arrayidx5, align 4
+  %iv.2 = add nuw nsw i64 %iv, 2
+  %arrayidx8 = getelementptr inbounds i32, ptr %a, i64 %iv.2
+  store i32 %1, ptr %arrayidx8, align 4
+  %iv.next = add nuw nsw i64 %iv, 3
+  %cmp = icmp ult i64 %iv.next, %len
+  br i1 %cmp, label %loop, label %loop.exit
+}