[test,instcombine] Precommit test for upcoming transform

Author: preames

llvm/test/Transforms/InstCombine/memcpy_alloca.ll

@@ -0,0 +1,94 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes=instcombine -S | FileCheck %s
+
+; Memcpy is copying known-undef, and is thus removable
+define void @test(i8* %dest) {
+; CHECK-LABEL: @test(
+; CHECK-NEXT:    [[A:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[SRC:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A]], i64 0, i64 0
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(7) [[DEST:%.*]], i8* noundef nonnull align 1 dereferenceable(7) [[SRC]], i64 7, i1 false)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %src = getelementptr inbounds [7 x i8], [7 x i8]* %a, i64 0, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 7, i1 false)
+  ret void
+}
+
+; Some non-undef elements
+define void @test2(i8* %dest) {
+; CHECK-LABEL: @test2(
+; CHECK-NEXT:    [[A:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[SRC:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A]], i64 0, i64 0
+; CHECK-NEXT:    store i8 0, i8* [[SRC]], align 1
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(7) [[DEST:%.*]], i8* noundef nonnull align 1 dereferenceable(7) [[SRC]], i64 7, i1 false)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %src = getelementptr inbounds [7 x i8], [7 x i8]* %a, i64 0, i64 0
+  store i8 0, i8* %src
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 7, i1 false)
+  ret void
+}
+
+; Volatile write is still required
+define void @test3(i8* %dest) {
+; CHECK-LABEL: @test3(
+; CHECK-NEXT:    [[A:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[SRC:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A]], i64 0, i64 0
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DEST:%.*]], i8* [[SRC]], i64 7, i1 true)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %src = getelementptr inbounds [7 x i8], [7 x i8]* %a, i64 0, i64 0
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 7, i1 true)
+  ret void
+}
+
+define void @test4(i8* %dest) {
+; CHECK-LABEL: @test4(
+; CHECK-NEXT:    [[A1:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[A1_SUB:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A1]], i64 0, i64 0
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(7) [[DEST:%.*]], i8* noundef nonnull align 1 dereferenceable(7) [[A1_SUB]], i64 7, i1 false)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %src = bitcast [7 x i8]* %a to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 7, i1 false)
+  ret void
+}
+
+define void @test5(i8* %dest) {
+; CHECK-LABEL: @test5(
+; CHECK-NEXT:    [[A:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[P2:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A]], i64 0, i64 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(3) [[DEST:%.*]], i8* noundef nonnull align 1 dereferenceable(3) [[P2]], i64 3, i1 false)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %p1 = bitcast [7 x i8]* %a to i32*
+  %p2 = getelementptr i32, i32* %p1, i32 1
+  %src = bitcast i32* %p2 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 3, i1 false)
+  ret void
+}
+
+define void @test6(i8* %dest) {
+; CHECK-LABEL: @test6(
+; CHECK-NEXT:    [[A:%.*]] = alloca [7 x i8], align 1
+; CHECK-NEXT:    [[P2:%.*]] = getelementptr inbounds [7 x i8], [7 x i8]* [[A]], i64 0, i64 2
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[P2]] to i16*
+; CHECK-NEXT:    store i16 42, i16* [[TMP1]], align 2
+; CHECK-NEXT:    call void @llvm.memcpy.p0i8.p0i8.i64(i8* noundef nonnull align 1 dereferenceable(7) [[DEST:%.*]], i8* noundef nonnull align 1 dereferenceable(7) [[P2]], i64 7, i1 false)
+; CHECK-NEXT:    ret void
+;
+  %a = alloca [7 x i8]
+  %p1 = bitcast [7 x i8]* %a to i16*
+  %p2 = getelementptr i16, i16* %p1, i32 1
+  store i16 42, i16* %p2
+  %src = bitcast i16* %p2 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dest, i8* %src, i64 7, i1 false)
+  ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i1)