[MemCpyOpt] Introduce test for PR101930 (NFC)

Author: antoniofrighetto

llvm/test/Transforms/MemCpyOpt/memset-memmove-redundant-memmove.ll

@@ -0,0 +1,89 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=memcpyopt -S %s -verify-memoryssa | FileCheck %s
+
+; Redundant memmove.
+define i32 @test() {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:    [[ARRAY:%.*]] = alloca [26 x i32], align 16
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], i8 0, i64 104, i1 false)
+; CHECK-NEXT:    [[ARRAY_IDX:%.*]] = getelementptr inbounds i8, ptr [[ARRAY]], i64 4
+; CHECK-NEXT:    call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], ptr noundef nonnull align 4 [[ARRAY_IDX]], i64 100, i1 false)
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, ptr [[ARRAY]], align 16
+; CHECK-NEXT:    ret i32 [[VAL]]
+;
+  %array = alloca [26 x i32], align 16
+  call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 %array, i8 0, i64 104, i1 false)
+  %array.idx = getelementptr inbounds i8, ptr %array, i64 4
+  call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 %array, ptr noundef nonnull align 4 %array.idx, i64 100, i1 false)
+  %val = load i32, ptr %array, align 16
+  ret i32 %val
+}
+
+; Used memmmove, buffer is reset to zero.
+define i32 @test1() {
+; CHECK-LABEL: @test1(
+; CHECK-NEXT:    [[ARRAY:%.*]] = alloca [26 x i32], align 16
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], i8 0, i64 104, i1 false)
+; CHECK-NEXT:    [[ARRAY_IDX:%.*]] = getelementptr inbounds i8, ptr [[ARRAY]], i64 4
+; CHECK-NEXT:    store i32 1, ptr [[ARRAY_IDX]], align 4
+; CHECK-NEXT:    call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], ptr noundef nonnull align 4 [[ARRAY_IDX]], i64 100, i1 false)
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, ptr [[ARRAY_IDX]], align 4
+; CHECK-NEXT:    ret i32 [[VAL]]
+;
+  %array = alloca [26 x i32], align 16
+  call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 %array, i8 0, i64 104, i1 false)
+  %array.idx = getelementptr inbounds i8, ptr %array, i64 4
+  store i32 1, ptr %array.idx
+  call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 %array, ptr noundef nonnull align 4 %array.idx, i64 100, i1 false)
+  %val = load i32, ptr %array.idx, align 4
+  ret i32 %val
+}
+
+; Used memmove, buffer clobbered by opaque.
+define i32 @test2() {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:    [[ARRAY:%.*]] = alloca [25 x i32], align 16
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 dereferenceable(100) [[ARRAY]], i8 0, i64 100, i1 false)
+; CHECK-NEXT:    call void @opaque(ptr noundef nonnull [[ARRAY]])
+; CHECK-NEXT:    [[ARRAY_IDX:%.*]] = getelementptr inbounds i8, ptr [[ARRAY]], i64 4
+; CHECK-NEXT:    call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 dereferenceable(96) [[ARRAY]], ptr noundef nonnull align 4 dereferenceable(96) [[ARRAY_IDX]], i64 96, i1 false)
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, ptr [[ARRAY]], align 16
+; CHECK-NEXT:    ret i32 [[VAL]]
+;
+  %array = alloca [25 x i32], align 16
+  call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 dereferenceable(100) %array, i8 0, i64 100, i1 false)
+  call void @opaque(ptr noundef nonnull %array)
+  %array.idx = getelementptr inbounds i8, ptr %array, i64 4
+  call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 dereferenceable(96) %array, ptr noundef nonnull align 4 dereferenceable(96) %array.idx, i64 96, i1 false)
+  %val = load i32, ptr %array, align 16
+  ret i32 %val
+}
+
+; Redundant memmove, but not within the same basic block.
+define i32 @test3() {
+; CHECK-LABEL: @test3(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[ARRAY:%.*]] = alloca [26 x i32], align 16
+; CHECK-NEXT:    call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], i8 0, i64 104, i1 false)
+; CHECK-NEXT:    [[ARRAY_IDX:%.*]] = getelementptr inbounds i8, ptr [[ARRAY]], i64 4
+; CHECK-NEXT:    br label [[USE:%.*]]
+; CHECK:       use:
+; CHECK-NEXT:    call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 [[ARRAY]], ptr noundef nonnull align 4 [[ARRAY_IDX]], i64 100, i1 false)
+; CHECK-NEXT:    [[VAL:%.*]] = load i32, ptr [[ARRAY]], align 16
+; CHECK-NEXT:    ret i32 [[VAL]]
+;
+entry:
+  %array = alloca [26 x i32], align 16
+  call void @llvm.memset.p0.i64(ptr noundef nonnull align 16 %array, i8 0, i64 104, i1 false)
+  %array.idx = getelementptr inbounds i8, ptr %array, i64 4
+  br label %use
+
+use:                                              ; preds = %entry
+  call void @llvm.memmove.p0.p0.i64(ptr noundef nonnull align 16 %array, ptr noundef nonnull align 4 %array.idx, i64 100, i1 false)
+  %val = load i32, ptr %array, align 16
+  ret i32 %val
+}
+
+declare void @opaque(ptr)
+declare void @llvm.memset.p0.i64(ptr nocapture, i8, i64, i1)
+declare void @llvm.memmove.p0.p0.i64(ptr nocapture, ptr nocapture, i64, i1) nounwind