Index: llvm/test/Transforms/MemCpyOpt/memcpy.ll
===================================================================
--- llvm/test/Transforms/MemCpyOpt/memcpy.ll
+++ llvm/test/Transforms/MemCpyOpt/memcpy.ll
@@ -391,3 +391,106 @@
 
 declare void @f1(ptr nocapture sret(%struct.big))
 declare void @f2(ptr)
+
+declare void @f_noattr(ptr)
+declare void @f_full_readonly(ptr nocapture noalias readonly)
+declare void @f_full_readnone(ptr nocapture noalias readnone)
+declare void @f_full_memory_none(ptr nocapture noalias) memory(none)
+declare void @f_noa(ptr noalias)
+
+; TODO: remove memcpy, which is guaranteed to be invariant
+; before and after the call because of its attributes.
+define void @immut_param1(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param1(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_noattr(ptr noalias nocapture readonly align 4 [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_noattr(ptr align 4 nocapture noalias readonly %val1)
+  ret void
+}
+
+; TODO: remove memcpy
+define void @immut_param2_readonly(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param2(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_fullattr_immut(ptr align 4 [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_full_readonly(ptr align 4 %val1)
+  ret void
+}
+
+define void @immut_param2_readnone(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param2(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_fullattr_immut(ptr align 4 [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_full_readnone(ptr align 4 %val1)
+  ret void
+}
+
+define void @immut_param2_memory_none(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param2(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_fullattr_immut(ptr align 4 [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_full_memory_none(ptr align 4 %val1)
+  ret void
+}
+
+; TODO: remove memcpy, cause union of attributes on call-site
+; and palam shows immutability of arg ptr.
+define void @immut_param3(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param3(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_noa(ptr align 4 [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_noa(ptr align 4 %val1)
+  ret void
+}
+
+; can't remove memcpy because if the call doesn't specify the alignment,
+; then it is some target specific value that we can't know.
+define void @immut_param4_no_align(ptr align 4 noalias %val) {
+; CHECK-LABEL: @immut_param4_no_align(
+; CHECK-NEXT:  start:
+; CHECK-NEXT:    [[VAL1:%.*]] = alloca i8, align 4
+; CHECK-NEXT:    call void @llvm.memcpy.p0.p0.i64(ptr align 4 [[VAL1]], ptr align 4 [[VAL:%.*]], i64 1, i1 false)
+; CHECK-NEXT:    call void @f_fullattr_immut(ptr [[VAL1]])
+; CHECK-NEXT:    ret void
+;
+start:
+  %val1 = alloca i8, align 4
+  call void @llvm.memcpy.p0.p0.i64(ptr align 4 %val1, ptr align 4 %val, i64 1, i1 false)
+  call void @f_full_readonly(ptr %val1)
+  ret void
+}