durin42 added inline comments.
================
Comment at:
clang/test/CodeGen/catch-alignment-assumption-attribute-alloc_align-on-function-variable.cpp:55
// CHECK-NEXT: %[[ALIGNMENT_RELOADED:.*]] = load i64,
i64* %[[ALIGNMENT_ADDR]], align 8
- // CHECK-NEXT: %[[X_RETURNED:.*]] = call noundef i8**
@[[PASSTHROUGH]](i8** noundef %[[X_RELOADED]], i64 noundef
%[[ALIGNMENT_RELOADED]])
- // CHECK-SANITIZE-NEXT: %[[PTRINT:.*]] = ptrtoint i8**
%[[X_RETURNED]] to i64
- // CHECK-SANITIZE-NEXT: %[[MASK:.*]] = sub i64
%[[ALIGNMENT_RELOADED]], 1
- // CHECK-SANITIZE-NEXT: %[[MASKEDPTR:.*]] = and i64
%[[PTRINT]], %[[MASK]]
- // CHECK-SANITIZE-NEXT: %[[MASKCOND:.*]] = icmp eq i64
%[[MASKEDPTR]], 0
- // CHECK-SANITIZE-NEXT: %[[PTRINT_DUP:.*]] = ptrtoint i8**
%[[X_RETURNED]] to i64, !nosanitize
- // CHECK-SANITIZE-NEXT: br i1 %[[MASKCOND]], label
%[[CONT:.*]], label %[[HANDLER_ALIGNMENT_ASSUMPTION:[^,]+]],{{.*}} !nosanitize
- // CHECK-SANITIZE: [[HANDLER_ALIGNMENT_ASSUMPTION]]:
- // CHECK-SANITIZE-NORECOVER-NEXT: call void
@__ubsan_handle_alignment_assumption_abort(i8* bitcast ({ {{{.*}}}, {{{.*}}},
{{{.*}}}* }* @[[LINE_100_ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]],
i64 %[[ALIGNMENT_RELOADED]], i64 0){{.*}}, !nosanitize
- // CHECK-SANITIZE-RECOVER-NEXT: call void
@__ubsan_handle_alignment_assumption(i8* bitcast ({ {{{.*}}}, {{{.*}}},
{{{.*}}}* }* @[[LINE_100_ALIGNMENT_ASSUMPTION]] to i8*), i64 %[[PTRINT_DUP]],
i64 %[[ALIGNMENT_RELOADED]], i64 0){{.*}}, !nosanitize
- // CHECK-SANITIZE-TRAP-NEXT: call void @llvm.ubsantrap(i8
23){{.*}}, !nosanitize
- // CHECK-SANITIZE-UNREACHABLE-NEXT: unreachable, !nosanitize
- // CHECK-SANITIZE: [[CONT]]:
- // CHECK-NEXT: call void @llvm.assume(i1 true) [
"align"(i8** %[[X_RETURNED]], i64 %1) ]
+ // CHECK-NEXT: %[[X_RETURNED:.*]] = call noundef i8**
@[[PASSTHROUGH]](i8** noundef %[[X_RELOADED]], i64 allocalign noundef
%[[ALIGNMENT_RELOADED]])
// CHECK-NEXT: ret i8** %[[X_RETURNED]]
----------------
lebedev.ri wrote:
> durin42 wrote:
> > lebedev.ri wrote:
> > > This is a regression, the old behavior was correct.
> > I don't think so: we now (as of D121629) check the alignment of the
> > returned pointer in the callee instead of the caller, and LLVM knows about
> > allocalign implying an alignment at the callsite. So I think it's correctly
> > optimizing away the sanitizer checks here.
> >
> > You or @jyknight will need to correct me if my understanding is incorrect
> > here, but my understanding was that this change was what motivated D121629
> > in the first place.
> I'm saying that as the author of said test and it's behavior.
How is this wrong though? Are you concerned because the `allocalign` isn't
being asserted upon by the sanitizer in the caller? How this a problem given
that the callee code now does the assertions in sanitizer mode?
(If I'm not understanding please elaborate: this is my first nontrivial work on
LLVM, so I'm going to need more than "I wrote this, and you are wrong" by way
of help understanding my error.)
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D119271/new/
https://reviews.llvm.org/D119271
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