[llvm] Reapply "[LowerMemIntrinsics] Use correct alignment in residual loop for variable llvm.memcpy" (PR #98482)

Thu Jul 11 06:43:10 PDT 2024

llvmbot wrote:



@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-backend-amdgpu

Author: Fabian Ritter (ritter-x2a)

<details>
<summary>Changes</summary>

Reverts llvm/llvm-project#98295, which reverted llvm/llvm-project#97998

The failure in the "InOneWeekend" test of the HIP test suite on clang-hip-vega20 (https://lab.llvm.org/buildbot/#/builders/123/builds/1498) seems to be unrelated; I observed it (and a similar failure for the "TheNextWeek" test in the same suite) intermittently on my system, with and without the patch applied. (It occurred in 2 out of 50 repeated runs without the patch and in 1 out of 50 runs with the patch.)

I suggest reapplying the patch for now; eventually we should look into fixing the tests.

---
Full diff: https://github.com/llvm/llvm-project/pull/98482.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp (+6-3) 
- (modified) llvm/test/CodeGen/AMDGPU/lower-mem-intrinsics.ll (+12-12) 


``````````diff

diff --git a/llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp b/llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp
index d2814f07530d8..b38db412f786a 100644
--- a/llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp
+++ b/llvm/lib/Transforms/Utils/LowerMemIntrinsics.cpp
@@ -262,6 +262,9 @@ void llvm::createMemCpyLoopUnknownSize(
     assert((ResLoopOpSize == AtomicElementSize ? *AtomicElementSize : 1) &&
            "Store size is expected to match type size");
 
+    Align ResSrcAlign(commonAlignment(PartSrcAlign, ResLoopOpSize));
+    Align ResDstAlign(commonAlignment(PartDstAlign, ResLoopOpSize));
+
     Value *RuntimeResidual = getRuntimeLoopRemainder(DL, PLBuilder, CopyLen,
                                                      CILoopOpSize, LoopOpSize);
     Value *RuntimeBytesCopied = PLBuilder.CreateSub(CopyLen, RuntimeResidual);
@@ -303,7 +306,7 @@ void llvm::createMemCpyLoopUnknownSize(
     Value *SrcGEP =
         ResBuilder.CreateInBoundsGEP(ResLoopOpType, SrcAddr, FullOffset);
     LoadInst *Load = ResBuilder.CreateAlignedLoad(ResLoopOpType, SrcGEP,
-                                                  PartSrcAlign, SrcIsVolatile);
+                                                  ResSrcAlign, SrcIsVolatile);
     if (!CanOverlap) {
       // Set alias scope for loads.
       Load->setMetadata(LLVMContext::MD_alias_scope,
@@ -311,8 +314,8 @@ void llvm::createMemCpyLoopUnknownSize(
     }
     Value *DstGEP =
         ResBuilder.CreateInBoundsGEP(ResLoopOpType, DstAddr, FullOffset);
-    StoreInst *Store = ResBuilder.CreateAlignedStore(Load, DstGEP, PartDstAlign,
-                                                     DstIsVolatile);
+    StoreInst *Store =
+        ResBuilder.CreateAlignedStore(Load, DstGEP, ResDstAlign, DstIsVolatile);
     if (!CanOverlap) {
       // Indicate that stores don't overlap loads.
       Store->setMetadata(LLVMContext::MD_noalias, MDNode::get(Ctx, NewScope));
diff --git a/llvm/test/CodeGen/AMDGPU/lower-mem-intrinsics.ll b/llvm/test/CodeGen/AMDGPU/lower-mem-intrinsics.ll
index d53db69f9f2e0..5cb57ee112b3a 100644
--- a/llvm/test/CodeGen/AMDGPU/lower-mem-intrinsics.ll
+++ b/llvm/test/CodeGen/AMDGPU/lower-mem-intrinsics.ll
@@ -930,9 +930,9 @@ define amdgpu_kernel void @memcpy_global_align4_global_align4_variable(ptr addrs
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i64 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i64 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[SRC]], i64 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 4
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[DST]], i64 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 4
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i64 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i64 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]
@@ -966,9 +966,9 @@ define amdgpu_kernel void @memcpy_global_align2_global_align2_variable(ptr addrs
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i64 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i64 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[SRC]], i64 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 2
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[DST]], i64 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 2
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i64 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i64 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]
@@ -1038,9 +1038,9 @@ define amdgpu_kernel void @memcpy_local_align4_local_align4_variable(ptr addrspa
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i32 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i32 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[SRC]], i32 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 4
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[DST]], i32 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 4
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i32 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i32 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]
@@ -1074,9 +1074,9 @@ define amdgpu_kernel void @memcpy_local_align2_local_align2_variable(ptr addrspa
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i32 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i32 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[SRC]], i32 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 2
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[DST]], i32 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 2
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i32 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i32 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]
@@ -1146,9 +1146,9 @@ define amdgpu_kernel void @memcpy_local_align4_global_align4_variable(ptr addrsp
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i32 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i32 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[SRC]], i32 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 4
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(1) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[DST]], i32 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 4
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(3) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i32 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i32 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]
@@ -1182,9 +1182,9 @@ define amdgpu_kernel void @memcpy_global_align4_local_align4_variable(ptr addrsp
 ; OPT-NEXT:    [[RESIDUAL_LOOP_INDEX:%.*]] = phi i32 [ 0, [[LOOP_MEMCPY_RESIDUAL_HEADER]] ], [ [[TMP14:%.*]], [[LOOP_MEMCPY_RESIDUAL:%.*]] ]
 ; OPT-NEXT:    [[TMP10:%.*]] = add i32 [[TMP3]], [[RESIDUAL_LOOP_INDEX]]
 ; OPT-NEXT:    [[TMP11:%.*]] = getelementptr inbounds i8, ptr addrspace(3) [[SRC]], i32 [[TMP10]]
-; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 4
+; OPT-NEXT:    [[TMP12:%.*]] = load i8, ptr addrspace(3) [[TMP11]], align 1
 ; OPT-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i8, ptr addrspace(1) [[DST]], i32 [[TMP10]]
-; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 4
+; OPT-NEXT:    store i8 [[TMP12]], ptr addrspace(1) [[TMP13]], align 1
 ; OPT-NEXT:    [[TMP14]] = add i32 [[RESIDUAL_LOOP_INDEX]], 1
 ; OPT-NEXT:    [[TMP15:%.*]] = icmp ult i32 [[TMP14]], [[TMP2]]
 ; OPT-NEXT:    br i1 [[TMP15]], label [[LOOP_MEMCPY_RESIDUAL]], label [[POST_LOOP_MEMCPY_EXPANSION:%.*]]

``````````

</details>


https://github.com/llvm/llvm-project/pull/98482
