[InterleavedAccessPass]: Ensure that dead nodes get erased only once

[hassnaaHamdi]

Use SmallSetVector instead of SmallVector to avoid duplication,
so that dead nodes get erased/deleted only once.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Hassnaa Hamdi (hassnaaHamdi)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/122643.diff

2 Files Affected:

• (modified) llvm/lib/CodeGen/InterleavedAccessPass.cpp (+2-1)
• (modified) llvm/test/Transforms/InterleavedAccess/AArch64/sve-interleave4.ll (+14)

diff --git a/llvm/lib/CodeGen/InterleavedAccessPass.cpp b/llvm/lib/CodeGen/InterleavedAccessPass.cpp
index 8b6e3180986c30..a197e1c7e4b202 100644
--- a/llvm/lib/CodeGen/InterleavedAccessPass.cpp
+++ b/llvm/lib/CodeGen/InterleavedAccessPass.cpp
@@ -545,7 +545,8 @@ bool InterleavedAccessImpl::runOnFunction(Function &F) {
   }
 
   for (auto *I : DeadInsts)
-    I->eraseFromParent();
+    if (I->getParent())
+      I->eraseFromParent();
 
   return Changed;
 }
diff --git a/llvm/test/Transforms/InterleavedAccess/AArch64/sve-interleave4.ll b/llvm/test/Transforms/InterleavedAccess/AArch64/sve-interleave4.ll
index e8d113ae3763d7..085089978d8f51 100644
--- a/llvm/test/Transforms/InterleavedAccess/AArch64/sve-interleave4.ll
+++ b/llvm/test/Transforms/InterleavedAccess/AArch64/sve-interleave4.ll
@@ -55,3 +55,17 @@ define void @mix_interleave4_interleave2(ptr %dst1, ptr %dst2, <vscale x 4 x i32
   store <vscale x 8 x i32> %interleaved, ptr %dst2, align 4
   ret void
 }
+
+; This case tests when the interleave is using same parameter twice,
+; the dead parameter will not get deleted twice.
+define void @duplicate_by_interleave(<vscale x 4 x i32> %A, <vscale x 4 x i32> %B, ptr writeonly %AB_duplicate) {
+; CHECK-LABEL: define void @duplicate_by_interleave
+; CHECK-SAME: (<vscale x 4 x i32> [[A:%.*]], <vscale x 4 x i32> [[B:%.*]], ptr writeonly [[AB_DUPLICATE:%.*]]) #[[ATTR0]] {
+; CHECK-NEXT:    call void @llvm.aarch64.sve.st4.nxv4i32(<vscale x 4 x i32> [[A]], <vscale x 4 x i32> [[A]], <vscale x 4 x i32> [[B]], <vscale x 4 x i32> [[B]], <vscale x 4 x i1> splat (i1 true), ptr [[AB_DUPLICATE]])
+; CHECK-NEXT:    ret void
+;
+  %interleave = tail call <vscale x 8 x i32> @llvm.vector.interleave2.nxv8i32(<vscale x 4 x i32> %A, <vscale x 4 x i32> %B)
+  %duplicate_by_interleave = tail call <vscale x 16 x i32> @llvm.vector.interleave2.nxv16i32(<vscale x 8 x i32> %interleave, <vscale x 8 x i32> %interleave)
+  store <vscale x 16 x i32> %duplicate_by_interleave, ptr %AB_duplicate, align 4
+  ret void
+}

[david-arm]

It looks like you're trying to fix a scenario where the same Instruction is included twice in DeadInsts, right? I think the problem here is that I may have been deleted and so you're dereferencing unreliable contents in memory or we could seg fault. I think you probably need to fix this a different way either by:

1. Keeping track of which instructions you've deleted, i.e. by maintaining a map of visited instructions. Or,
2. Removing duplicate dead instructions from the list before iterating over them.

[davemgreen]

Could it use SmallSetVector to store the Dead instructions? It should rule out any duplicated whilst keeping them in order, so that they are removed in the correct order.

[hassnaaHamdi]

Could it use SmallSetVector to store the Dead instructions? It should rule out any duplicated whilst keeping them in order, so that they are removed in the correct order.

I thought about this, but I found that there will be changes in other functions also.
but based on what @david-arm said, it seems that I will have to use SmallSetVector.
Thank you both.

[davemgreen]

LGTM

[llvm-ci]

LLVM Buildbot has detected a new failure on builder llvm-clang-x86_64-expensive-checks-debian running on gribozavr4 while building llvm at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/11951

Here is the relevant piece of the build log for the reference

Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: tools/llvm-gsymutil/ARM_AArch64/macho-merged-funcs-dwarf.yaml' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
Input file: /b/1/llvm-clang-x86_64-expensive-checks-debian/build/test/tools/llvm-gsymutil/ARM_AArch64/Output/macho-merged-funcs-dwarf.yaml.tmp.dSYM
Output file (aarch64): /b/1/llvm-clang-x86_64-expensive-checks-debian/build/test/tools/llvm-gsymutil/ARM_AArch64/Output/macho-merged-funcs-dwarf.yaml.tmp.default.gSYM
Loaded 3 functions from DWARF.
Loaded 3 functions from symbol table.
warning: same address range contains different debug info. Removing:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000047
addr=0x0000000000000248, file=  3, line=  5
addr=0x0000000000000254, file=  3, line=  7
addr=0x0000000000000258, file=  3, line=  9
addr=0x000000000000025c, file=  3, line=  8
addr=0x0000000000000260, file=  3, line= 11
addr=0x0000000000000264, file=  3, line= 10
addr=0x0000000000000268, file=  3, line=  6


In favor of this one:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000001
addr=0x0000000000000248, file=  1, line=  5
addr=0x0000000000000254, file=  1, line=  7
addr=0x0000000000000258, file=  1, line=  9
addr=0x000000000000025c, file=  1, line=  8
addr=0x0000000000000260, file=  1, line= 11
addr=0x0000000000000264, file=  1, line= 10
addr=0x0000000000000268, file=  1, line=  6


warning: same address range contains different debug info. Removing:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000001
addr=0x0000000000000248, file=  1, line=  5
addr=0x0000000000000254, file=  1, line=  7
addr=0x0000000000000258, file=  1, line=  9
addr=0x000000000000025c, file=  1, line=  8
addr=0x0000000000000260, file=  1, line= 11
addr=0x0000000000000264, file=  1, line= 10
addr=0x0000000000000268, file=  1, line=  6


In favor of this one:
[0x0000000000000248 - 0x0000000000000270): Name=0x00000030
addr=0x0000000000000248, file=  2, line=  5
addr=0x0000000000000254, file=  2, line=  7
addr=0x0000000000000258, file=  2, line=  9
addr=0x000000000000025c, file=  2, line=  8
addr=0x0000000000000260, file=  2, line= 11
addr=0x0000000000000264, file=  2, line= 10
...