[llvm] bbff5b8 - [VPlan] Use alloc-type to compute interleave group offset.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2024-10-16T07:21:58+01:00
New Revision: bbff5b8891c0ce929d6ace2d86ea6891425042e2

URL: https://github.com/llvm/llvm-project/commit/bbff5b8891c0ce929d6ace2d86ea6891425042e2
DIFF: https://github.com/llvm/llvm-project/commit/bbff5b8891c0ce929d6ace2d86ea6891425042e2.diff

LOG: [VPlan] Use alloc-type to compute interleave group offset.

Use getAllocTypeSize to get compute the offset to the start of
interleave groups instead getScalarSizeInBits, which may return 0 for
pointers. This is in line with the analysis building the interleave
groups and fixes a mis-compile reported for
https://github.com/llvm/llvm-project/pull/106431.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
    llvm/test/Transforms/LoopVectorize/interleaved-accesses-different-insert-position.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
index 4443a7be4ad45b..faec08cac18751 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanTransforms.cpp
@@ -1646,8 +1646,9 @@ void VPlanTransforms::createInterleaveGroups(
       // zero.
       assert(IG->getIndex(IRInsertPos) != 0 &&
              "index of insert position shouldn't be zero");
+      auto &DL = IRInsertPos->getDataLayout();
       APInt Offset(32,
-                   getLoadStoreType(IRInsertPos)->getScalarSizeInBits() / 8 *
+                   DL.getTypeAllocSize(getLoadStoreType(IRInsertPos)) *
                        IG->getIndex(IRInsertPos),
                    /*IsSigned=*/true);
       VPValue *OffsetVPV = Plan.getOrAddLiveIn(

diff  --git a/llvm/test/Transforms/LoopVectorize/interleaved-accesses-
diff erent-insert-position.ll b/llvm/test/Transforms/LoopVectorize/interleaved-accesses-
diff erent-insert-position.ll
index 665fd1b9aeacaa..5913bae082f1da 100644
--- a/llvm/test/Transforms/LoopVectorize/interleaved-accesses-
diff erent-insert-position.ll
+++ b/llvm/test/Transforms/LoopVectorize/interleaved-accesses-
diff erent-insert-position.ll
@@ -183,7 +183,7 @@ define i64 @interleave_group_load_pointer_type(ptr %start, ptr %end) {
 ; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[OFFSET_IDX]], 0
 ; CHECK-NEXT:    [[NEXT_GEP:%.*]] = getelementptr i8, ptr [[START]], i64 [[TMP6]]
 ; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr i8, ptr [[NEXT_GEP]], i64 16
-; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[TMP7]], i32 0
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr i8, ptr [[TMP7]], i32 -8
 ; CHECK-NEXT:    [[WIDE_VEC:%.*]] = load <12 x ptr>, ptr [[TMP8]], align 8
 ; CHECK-NEXT:    [[STRIDED_VEC:%.*]] = shufflevector <12 x ptr> [[WIDE_VEC]], <12 x ptr> poison, <4 x i32> <i32 0, i32 3, i32 6, i32 9>
 ; CHECK-NEXT:    [[STRIDED_VEC3:%.*]] = shufflevector <12 x ptr> [[WIDE_VEC]], <12 x ptr> poison, <4 x i32> <i32 1, i32 4, i32 7, i32 10>