[PATCH] D9379: llvm.noalias - don't interfere with llvm.assume

[Philip Reames via llvm-commits]

Hal, several of these have been previously approved.  Please either land 
them or close them.  We trust you to rebase correctly and call out 
anything that needs particular attention.  :)


On 08/14/2017 07:51 PM, Hal Finkel via Phabricator wrote:
> hfinkel updated this revision to Diff 111117.
> hfinkel added a comment.
>
> Rebased.
>
>
> https://reviews.llvm.org/D9379
>
> Files:
>    lib/Analysis/ValueTracking.cpp
>    test/Transforms/InstCombine/assume.ll
>
>
> Index: test/Transforms/InstCombine/assume.ll
> ===================================================================
> --- test/Transforms/InstCombine/assume.ll
> +++ test/Transforms/InstCombine/assume.ll
> @@ -275,6 +275,26 @@
>     ret i1 %rval
>   }
>   
> +define i1 @nonnull5(i32** %a) {
> +entry:
> +  %load = load i32*, i32** %a
> +  ;; This call cannot actually trap, and so should not disrupt the assume.
> +  %v = call i32* @llvm.noalias.p0i32(i32* %load, metadata !1)
> +  %cmp = icmp ne i32* %load, null
> +  tail call void @llvm.assume(i1 %cmp)
> +  %q = bitcast i32** %a to i32*
> +  %rval = icmp eq i32* %v, %q
> +  ret i1 %rval
> +
> +; CHECK-LABEL: @nonnull5
> +; CHECK: !nonnull
> +; CHECK-NOT: call void @llvm.assume
> +}
> +
> +declare i32* @llvm.noalias.p0i32(i32*, metadata) nounwind
> +
> +!0 = !{!0, !"some domain"}
> +!1 = !{!1, !0, !"some scope"}
>   
>   attributes #0 = { nounwind uwtable }
>   attributes #1 = { nounwind }
> Index: lib/Analysis/ValueTracking.cpp
> ===================================================================
> --- lib/Analysis/ValueTracking.cpp
> +++ lib/Analysis/ValueTracking.cpp
> @@ -411,6 +411,7 @@
>         case Intrinsic::invariant_end:
>         case Intrinsic::lifetime_start:
>         case Intrinsic::lifetime_end:
> +      case Intrinsic::noalias:
>         case Intrinsic::objectsize:
>         case Intrinsic::ptr_annotation:
>         case Intrinsic::var_annotation:
>
>