[llvm] r372142 - Reland "[SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y)"

Roman Lebedev via llvm-commits llvm-commits at lists.llvm.org
Tue Sep 17 10:33:00 PDT 2019


On Tue, Sep 17, 2019 at 8:10 PM David Bolvansky via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
> Author: xbolva00
> Date: Tue Sep 17 10:12:24 2019
> New Revision: 372142
>
> URL: http://llvm.org/viewvc/llvm-project?rev=372142&view=rev
> Log:
> Reland "[SLC] Preserve attrs for strncpy(x, "", y) -> memset(align 1 x, '\0', y)"
Commit message does not mention anything about the revert, or why it's
being recommitted.

> Modified:
>     llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
>     llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll
>
> Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=372142&r1=372141&r2=372142&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
> +++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Tue Sep 17 10:12:24 2019
> @@ -610,7 +610,10 @@ Value *LibCallSimplifier::optimizeStrNCp
>
>    if (SrcLen == 0) {
>      // strncpy(x, "", y) -> memset(align 1 x, '\0', y)
> -    B.CreateMemSet(Dst, B.getInt8('\0'), Size, 1);
> +    CallInst *NewCI = B.CreateMemSet(Dst, B.getInt8('\0'), Size, 1);
> +    AttrBuilder ArgAttrs(CI->getAttributes().getParamAttributes(0));
> +    NewCI->setAttributes(NewCI->getAttributes().addParamAttributes(
> +        CI->getContext(), 0, ArgAttrs));
>      return Dst;
>    }
>
>
> Modified: llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll?rev=372142&r1=372141&r2=372142&view=diff
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll (original)
> +++ llvm/trunk/test/Transforms/InstCombine/strncpy-1.ll Tue Sep 17 10:12:24 2019
> @@ -134,6 +134,16 @@ define i8* @test2(i8* %dst) {
>    ret i8* %ret
>  }
>
> +define i8* @test3(i8* %dst, i32 %n) {
> +; CHECK-LABEL: @test3(
> +; CHECK-NEXT:    call void @llvm.memset.p0i8.i32(i8* noalias nonnull align 1 dereferenceable(5) [[DST:%.*]], i8 0, i32 5, i1 false)
> +; CHECK-NEXT:    ret i8* [[DST]]
> +;
> +  %src = getelementptr [1 x i8], [1 x i8]* @null, i32 0, i32 0
> +  %ret = call i8* @strncpy(i8* noalias nonnull %dst, i8* nonnull %src, i32 5);
> +  ret i8* %ret
> +}
> +
>  ; Check cases that shouldn't be simplified.
>
>  define void @test_no_simplify1() {
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits


More information about the llvm-commits mailing list