From 7bc99d38c051c67517696aef2644725e140a57f0 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Tue, 13 Aug 2024 22:36:00 +0800 Subject: [PATCH 1/2] [MemCpyOpt] Avoid infinite loops in `MemCpyOptPass::processMemCpyMemCpyDependence` --- llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp | 4 ++++ llvm/test/Transforms/MemCpyOpt/pr102994.ll | 18 ++++++++++++++++++ 2 files changed, 22 insertions(+) create mode 100644 llvm/test/Transforms/MemCpyOpt/pr102994.ll diff --git a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp index 1d779128e454c..3f15fa2163d27 100644 --- a/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp +++ b/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp @@ -1193,6 +1193,10 @@ bool MemCpyOptPass::processMemCpyMemCpyDependence(MemCpyInst *M, CopySourceAlign = commonAlignment(*CopySourceAlign, MForwardOffset); } + // Avoid infinite loops + if (BAA.isMustAlias(M->getSource(), CopySource)) + return false; + // Verify that the copied-from memory doesn't change in between the two // transfers. For example, in: // memcpy(a <- b) diff --git a/llvm/test/Transforms/MemCpyOpt/pr102994.ll b/llvm/test/Transforms/MemCpyOpt/pr102994.ll new file mode 100644 index 0000000000000..53d6335f6e9d0 --- /dev/null +++ b/llvm/test/Transforms/MemCpyOpt/pr102994.ll @@ -0,0 +1,18 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5 +; RUN: opt -S -passes=memcpyopt < %s | FileCheck %s + +@g1 = external global i8 +@g2 = external global [64 x i8] + +define void @func() { +; CHECK-LABEL: define void @func() { +; CHECK-NEXT: [[ENTRY:.*:]] +; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr getelementptr inbounds (i8, ptr @g2, i64 16), ptr getelementptr inbounds nuw (i8, ptr @g2, i64 16), i64 20, i1 false) +; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr @g1, ptr getelementptr inbounds (i8, ptr @g2, i64 24), i64 1, i1 false) +; CHECK-NEXT: ret void +; +entry: + call void @llvm.memcpy.p0.p0.i64(ptr getelementptr inbounds (i8, ptr @g2, i64 16), ptr getelementptr inbounds nuw (i8, ptr @g2, i64 16), i64 20, i1 false) + call void @llvm.memcpy.p0.p0.i64(ptr @g1, ptr getelementptr inbounds (i8, ptr @g2, i64 24), i64 1, i1 false) + ret void +} From bd8d6dd19ca3f424751875d3d026749d6d935bd6 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Thu, 22 Aug 2024 15:47:09 +0800 Subject: [PATCH 2/2] [MemCpyOpt] Add new tests without constantexpr --- llvm/test/Transforms/MemCpyOpt/pr102994.ll | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/llvm/test/Transforms/MemCpyOpt/pr102994.ll b/llvm/test/Transforms/MemCpyOpt/pr102994.ll index 53d6335f6e9d0..9a782b9b3752a 100644 --- a/llvm/test/Transforms/MemCpyOpt/pr102994.ll +++ b/llvm/test/Transforms/MemCpyOpt/pr102994.ll @@ -3,6 +3,7 @@ @g1 = external global i8 @g2 = external global [64 x i8] +@g3 = global i8 0, align 1 define void @func() { ; CHECK-LABEL: define void @func() { @@ -16,3 +17,23 @@ entry: call void @llvm.memcpy.p0.p0.i64(ptr @g1, ptr getelementptr inbounds (i8, ptr @g2, i64 24), i64 1, i1 false) ret void } + +define void @func2(ptr %p) { +; CHECK-LABEL: define void @func2( +; CHECK-SAME: ptr [[P:%.*]]) { +; CHECK-NEXT: [[ENTRY:.*:]] +; CHECK-NEXT: [[GEP1:%.*]] = getelementptr i8, ptr [[P]], i64 32 +; CHECK-NEXT: [[GEP2:%.*]] = getelementptr i8, ptr [[P]], i64 34 +; CHECK-NEXT: [[GEP3:%.*]] = getelementptr i8, ptr [[P]], i64 32 +; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr [[GEP1]], ptr [[GEP3]], i64 32, i1 false) +; CHECK-NEXT: call void @llvm.memcpy.p0.p0.i64(ptr @g3, ptr [[GEP2]], i64 1, i1 false) +; CHECK-NEXT: ret void +; +entry: + %gep1 = getelementptr i8, ptr %p, i64 32 + %gep2 = getelementptr i8, ptr %p, i64 34 + %gep3 = getelementptr i8, ptr %p, i64 32 + call void @llvm.memcpy.p0.p0.i64(ptr %gep1, ptr %gep3, i64 32, i1 false) + call void @llvm.memcpy.p0.p0.i64(ptr @g3, ptr %gep2, i64 1, i1 false) + ret void +}