[LAA] increase test coverage in symbolic-stride

[artagnon]

The test symbolic-stride.ll does not exercise all codepaths in getStrideFromPointer, particularly when the operand is an SCEVIntegralCastExpr. Cover these codepaths as well. This patch serves as pre-commit tests for #92119.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

Author: Ramkumar Ramachandra (artagnon)

Changes

The test symbolic-stride.ll does not exercise all codepaths in getStrideFromPointer, particularly when the operand is an SCEVIntegralCastExpr. Cover these codepaths as well.

---

Full diff: https://github.com/llvm/llvm-project/pull/92253.diff

1 Files Affected:

• (modified) llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll (+121)

diff --git a/llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll b/llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll
index 6cc045d7a681b..3da0f543c5c1c 100644
--- a/llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll
+++ b/llvm/test/Analysis/LoopAccessAnalysis/symbolic-stride.ll
@@ -95,6 +95,127 @@ exit:
   ret void
 }
 
+define void @single_stride_castexpr(i32 %offset, ptr %src, ptr %dst, i1 %cond) {
+; CHECK-LABEL: 'single_stride_castexpr'
+; CHECK-NEXT:    inner.loop:
+; CHECK-NEXT:      Memory dependences are safe with run-time checks
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Check 0:
+; CHECK-NEXT:        Comparing group ([[GRP1:0x[0-9a-f]+]]):
+; CHECK-NEXT:          %gep.dst = getelementptr i32, ptr %dst, i64 %iv.2
+; CHECK-NEXT:        Against group ([[GRP2:0x[0-9a-f]+]]):
+; CHECK-NEXT:          %gep.src = getelementptr inbounds i32, ptr %src, i32 %iv.3
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-NEXT:        Group [[GRP1]]:
+; CHECK-NEXT:          (Low: ((4 * %iv.1) + %dst) High: (804 + (4 * %iv.1) + %dst))
+; CHECK-NEXT:            Member: {((4 * %iv.1) + %dst),+,4}<%inner.loop>
+; CHECK-NEXT:        Group [[GRP2]]:
+; CHECK-NEXT:          (Low: %src High: (804 + %src))
+; CHECK-NEXT:            Member: {%src,+,4}<nuw><%inner.loop>
+; CHECK-EMPTY:
+; CHECK-NEXT:      Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT:      SCEV assumptions:
+; CHECK-NEXT:      Equal predicate: %offset == 1
+; CHECK-EMPTY:
+; CHECK-NEXT:      Expressions re-written:
+; CHECK-NEXT:      [PSE] %gep.dst = getelementptr i32, ptr %dst, i64 %iv.2:
+; CHECK-NEXT:        {((4 * %iv.1) + %dst),+,(4 * (sext i32 %offset to i64))<nsw>}<%inner.loop>
+; CHECK-NEXT:        --> {((4 * %iv.1) + %dst),+,4}<%inner.loop>
+; CHECK-NEXT:    outer.header:
+; CHECK-NEXT:      Report: loop is not the innermost loop
+; CHECK-NEXT:      Dependences:
+; 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:
+;
+entry:
+  %offset.ext = sext i32 %offset to i64
+  br label %outer.header
+
+outer.header:
+  %iv.1 = phi i64 [ 0, %entry ], [ %iv.2.next, %inner.loop ]
+  br i1 %cond, label %inner.loop, label %exit
+
+inner.loop:
+  %iv.2 = phi i64 [ %iv.1, %outer.header ], [ %iv.2.next, %inner.loop ]
+  %iv.3 = phi i32 [ 0, %outer.header ], [ %iv.3.next, %inner.loop ]
+  %gep.src = getelementptr inbounds i32, ptr %src, i32 %iv.3
+  %load = load i32, ptr %gep.src, align 8
+  %gep.dst = getelementptr i32, ptr %dst, i64 %iv.2
+  store i32 %load, ptr %gep.dst, align 8
+  %iv.2.next = add i64 %iv.2, %offset.ext
+  %iv.3.next = add i32 %iv.3, 1
+  %ec = icmp eq i32 %iv.3, 200
+  br i1 %ec, label %outer.header, label %inner.loop
+
+exit:
+  ret void
+}
+
+define void @single_stride_castexpr_multiuse(i32 %offset, ptr %src, ptr %dst, i1 %cond) {
+; CHECK-LABEL: 'single_stride_castexpr_multiuse'
+; CHECK-NEXT:    inner.loop:
+; CHECK-NEXT:      Memory dependences are safe with run-time checks
+; CHECK-NEXT:      Dependences:
+; CHECK-NEXT:      Run-time memory checks:
+; CHECK-NEXT:      Check 0:
+; CHECK-NEXT:        Comparing group ([[GRP3:0x[0-9a-f]+]]):
+; CHECK-NEXT:          %gep.dst = getelementptr i32, ptr %dst, i64 %iv.2
+; CHECK-NEXT:        Against group ([[GRP4:0x[0-9a-f]+]]):
+; CHECK-NEXT:          %gep.src = getelementptr inbounds i32, ptr %src, i64 %iv.3
+; CHECK-NEXT:      Grouped accesses:
+; CHECK-NEXT:        Group [[GRP3]]:
+; CHECK-NEXT:          (Low: (((4 * %iv.1) + %dst) umin ((4 * %iv.1) + (4 * (sext i32 %offset to i64) * (200 + (-1 * (zext i32 %offset to i64))<nsw>)<nsw>) + %dst)) High: (4 + (((4 * %iv.1) + %dst) umax ((4 * %iv.1) + (4 * (sext i32 %offset to i64) * (200 + (-1 * (zext i32 %offset to i64))<nsw>)<nsw>) + %dst))))
+; CHECK-NEXT:            Member: {((4 * %iv.1) + %dst),+,(4 * (sext i32 %offset to i64))<nsw>}<%inner.loop>
+; CHECK-NEXT:        Group [[GRP4]]:
+; CHECK-NEXT:          (Low: ((4 * (zext i32 %offset to i64))<nuw><nsw> + %src) High: (804 + %src))
+; CHECK-NEXT:            Member: {((4 * (zext i32 %offset to i64))<nuw><nsw> + %src),+,4}<%inner.loop>
+; 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:
+; CHECK-NEXT:    outer.header:
+; CHECK-NEXT:      Report: loop is not the innermost loop
+; CHECK-NEXT:      Dependences:
+; 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:
+;
+entry:
+  %offset.ext = sext i32 %offset to i64
+  %offset.zext = zext i32 %offset to i64
+  br label %outer.header
+
+outer.header:
+  %iv.1 = phi i64 [ 0, %entry ], [ %iv.2.next, %inner.loop ]
+  br i1 %cond, label %inner.loop, label %exit
+
+inner.loop:
+  %iv.2 = phi i64 [ %iv.1, %outer.header ], [ %iv.2.next, %inner.loop ]
+  %iv.3 = phi i64 [ %offset.zext, %outer.header ], [ %iv.3.next, %inner.loop ]
+  %gep.src = getelementptr inbounds i32, ptr %src, i64 %iv.3
+  %load = load i32, ptr %gep.src, align 8
+  %gep.dst = getelementptr i32, ptr %dst, i64 %iv.2
+  store i32 %load, ptr %gep.dst, align 8
+  %iv.2.next = add i64 %iv.2, %offset.ext
+  %iv.3.next = add i64 %iv.3, 1
+  %ec = icmp eq i64 %iv.3, 200
+  br i1 %ec, label %outer.header, label %inner.loop
+
+exit:
+  ret void
+}
+
 ; A loop with two symbolic strides.
 define void @two_strides(ptr noalias %A, ptr noalias %B, i64 %N, i64 %stride.1, i64 %stride.2) {
 ; CHECK-LABEL: 'two_strides'

[fhahn]

LGTM, thanks!

would be good to mention that this patch adds extra tests for #92119