MemCpyOpt: combine local load/store sequences into memcpy.

Sort of the BB-local equivalent to idiom-recognizer: if we have a basic-block
that really implements a memcpy operation, backends can benefit from seeing
this.

llvm-svn: 269125

1 files changed, 353 insertions, 0 deletions

diff --git a/llvm/test/Transforms/MemCpyOpt/form-memcpy.ll b/llvm/test/Transforms/MemCpyOpt/form-memcpy.ll
new file mode 100644
index 00000000000..c381ffcd5aa
--- /dev/null
+++ b/llvm/test/Transforms/MemCpyOpt/form-memcpy.ll
@@ -0,0 +1,353 @@
+; RUN: opt < %s -memcpyopt -S | FileCheck %s
+
+define void @test_simple_memcpy(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_simple_memcpy
+; CHECK-DAG: [[DST:%.*]] = bitcast i32* %dst to i8*
+; CHECK-DAG: [[SRC:%.*]] = bitcast i32* %src to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i32 4, i1 false)
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_simple_memmove(i32* %dst, i32* %src) {
+; CHECK-LABEL: @test_simple_memmove
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+; Make sure we can handle calculating bases & offsets from a real memcpy.
+define void @test_initial_memcpy(i32* noalias %dst, i32* noalias%src) {
+; CHECK-LABEL: @test_initial_memcpy
+; CHECK: {{%.*}} = bitcast i32* %dst to i8*
+; CHECK: {{%.*}} = bitcast i32* %src to i8*
+; CHECK: [[DST:%.*]] = bitcast i32* %dst to i8*
+; CHECK: [[SRC:%.*]] = bitcast i32* %src to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i32 4, i1 false)
+
+  %dst.0 = bitcast i32* %dst to i8*
+  %src.0 = bitcast i32* %src to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %dst.0, i8* %src.0, i64 4, i32 4, i1 false)
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_volatile_skipped(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_volatile_skipped
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load volatile i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_atomic_skipped(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_atomic_skipped
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store atomic i32 %val.1, i32* %dst.1 unordered, align 4
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define i32 @test_multi_use_skipped(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_multi_use_skipped
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret i32 %val.1
+}
+
+define void @test_side_effect_skipped(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_side_effect_skipped
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  call void asm sideeffect "", ""()
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_holes_handled(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_holes_handled
+; CHECK-DAG: [[DST:%.*]] = bitcast i32* %dst to i8*
+; CHECK-DAG: [[SRC:%.*]] = bitcast i32* %src to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i32 4, i1 false)
+; CHECK-DAG: [[DST:%.*]] = bitcast i32* %dst.7 to i8*
+; CHECK-DAG: [[SRC:%.*]] = bitcast i32* %src.7 to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i32 4, i1 false)
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+
+  %src.7 = getelementptr i32, i32* %src, i32 7
+  %dst.7 = getelementptr i32, i32* %dst, i32 7
+  %val.7 = load i32, i32* %src.7
+  store i32 %val.7, i32* %dst.7
+
+  %src.9 = getelementptr i32, i32* %src, i32 9
+  %dst.9 = getelementptr i32, i32* %dst, i32 9
+  %val.9 = load i32, i32* %src.9
+  store i32 %val.9, i32* %dst.9
+
+  %src.10 = getelementptr i32, i32* %src, i32 10
+  %dst.10 = getelementptr i32, i32* %dst, i32 10
+  %val.10 = load i32, i32* %src.10
+  store i32 %val.10, i32* %dst.10
+
+  %src.8 = getelementptr i32, i32* %src, i32 8
+  %dst.8 = getelementptr i32, i32* %dst, i32 8
+  %val.8 = load i32, i32* %src.8
+  store i32 %val.8, i32* %dst.8
+
+  ret void
+}
+
+define void @test_offset_mismatch(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_offset_mismatch
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 1
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 2
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_non_idempotent_ops(i8* %dst, i8* %src) {
+; CHECK-LABEL: @test_non_idempotent_ops
+; CHECK-NOT: call void @llvm.memcpy
+; CHECK-NOT: call void @llvm.memmove
+
+  %val.0 = load i8, i8* %src
+  store i8 %val.0, i8* %dst
+
+  %src.2 = getelementptr i8, i8* %src, i8 2
+  %dst.2 = getelementptr i8, i8* %dst, i8 2
+  %val.2 = load i8, i8* %src.2
+  store i8 %val.2, i8* %dst.2
+
+  %val.0.dup = load i8, i8* %src
+  store i8 %val.0.dup, i8* %dst
+
+  %src.1 = getelementptr i8, i8* %src, i8 1
+  %dst.1 = getelementptr i8, i8* %dst, i8 1
+  %val.1 = load i8, i8* %src.1
+  store i8 %val.1, i8* %dst.1
+
+  %src.3 = getelementptr i8, i8* %src, i8 3
+  %dst.3 = getelementptr i8, i8* %dst, i8 3
+  %val.3 = load i8, i8* %src.3
+  store i8 %val.3, i8* %dst.3
+
+  ret void
+}
+
+define void @test_intervening_op(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_intervening_op
+; CHECK-NOT: call void @llvm.memcpy
+
+  %val.0 = load i32, i32* %src
+  store i32 %val.0, i32* %dst
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %src16.2 = bitcast i32* %src.2 to i16*
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val16.2 = load i16, i16* %src16.2
+  %val.2 = sext i16 %val16.2 to i32
+  store i32 %val.2, i32* %dst.2
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+define void @test_infer_align(i32* noalias %dst, i32* noalias %src) {
+; CHECK-LABEL: @test_infer_align
+; CHECK-DAG: [[DST:%.*]] = bitcast i32* %dst to i8*
+; CHECK-DAG: [[SRC:%.*]] = bitcast i32* %src to i8*
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64(i8* [[DST]], i8* [[SRC]], i64 16, i32 8, i1 false)
+
+  %src.2 = getelementptr i32, i32* %src, i32 2
+  %dst.2 = getelementptr i32, i32* %dst, i32 2
+  %val.2 = load i32, i32* %src.2
+  store i32 %val.2, i32* %dst.2
+
+  %val.0 = load i32, i32* %src, align 8
+  store i32 %val.0, i32* %dst, align 16
+
+  %src.1 = getelementptr i32, i32* %src, i32 1
+  %dst.1 = getelementptr i32, i32* %dst, i32 1
+  %val.1 = load i32, i32* %src.1
+  store i32 %val.1, i32* %dst.1
+
+  %src.3 = getelementptr i32, i32* %src, i32 3
+  %dst.3 = getelementptr i32, i32* %dst, i32 3
+  %val.3 = load i32, i32* %src.3
+  store i32 %val.3, i32* %dst.3
+
+  ret void
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1)