<div dir="ltr">This transform is only valid if the sprintf result is unused. sprintf returns the number of characters copied. strcpy just returns the destination pointer.<div><br clear="all"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">~Craig</div></div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Aug 13, 2020 at 4:19 PM Dávid Bolvanský via llvm-commits <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Ok, i will do next time.<br>
<br>
> Dňa 14. 8. 2020 o 1:15 užívateľ Eli Friedman <<a href="mailto:efriedma@quicinc.com" target="_blank">efriedma@quicinc.com</a>> napísal:<br>
> <br>
> I think I'd prefer to use pre-commit review for all functional changes to SimplifyLibCalls, even if you're confident the change is safe; it's very easy to get something subtly wrong.<br>
> <br>
> This patch LGTM.<br>
> <br>
> -Eli<br>
> <br>
> -----Original Message-----<br>
> From: llvm-commits <<a href="mailto:llvm-commits-bounces@lists.llvm.org" target="_blank">llvm-commits-bounces@lists.llvm.org</a>> On Behalf Of Dávid Bolvanský via llvm-commits<br>
> Sent: Thursday, August 13, 2020 3:08 PM<br>
> To: <a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a><br>
> Subject: [EXT] [llvm] ab9fc8b - [SLC] sprintf(dst, "%s", str) -> strcpy(dst, str)<br>
> <br>
> <br>
> Author: Dávid Bolvanský<br>
> Date: 2020-08-14T00:05:55+02:00<br>
> New Revision: ab9fc8bae805c785066779e76e7846aabad5609e<br>
> <br>
> URL: <a href="https://github.com/llvm/llvm-project/commit/ab9fc8bae805c785066779e76e7846aabad5609e" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/ab9fc8bae805c785066779e76e7846aabad5609e</a><br>
> DIFF: <a href="https://github.com/llvm/llvm-project/commit/ab9fc8bae805c785066779e76e7846aabad5609e.diff" rel="noreferrer" target="_blank">https://github.com/llvm/llvm-project/commit/ab9fc8bae805c785066779e76e7846aabad5609e.diff</a><br>
> <br>
> LOG: [SLC] sprintf(dst, "%s", str) -> strcpy(dst, str)<br>
> <br>
> Solves 46489<br>
> <br>
> Added:<br>
> <br>
> <br>
> Modified:<br>
> llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
> llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll<br>
> llvm/test/Transforms/InstCombine/sprintf-1.ll<br>
> <br>
> Removed:<br>
> <br>
> <br>
> <br>
> ################################################################################<br>
> diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
> index 2f6e60fc09c4..b5f0f56029a4 100644<br>
> --- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
> +++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp<br>
> @@ -2487,21 +2487,11 @@ Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI,<br>
> }<br>
> <br>
> if (FormatStr[1] == 's') {<br>
> - // sprintf(dest, "%s", str) -> llvm.memcpy(align 1 dest, align 1 str,<br>
> - // strlen(str)+1)<br>
> + // sprintf(dest, "%s", str) -> strcpy(dest, str)<br>
> if (!CI->getArgOperand(2)->getType()->isPointerTy())<br>
> return nullptr;<br>
> <br>
> - Value *Len = emitStrLen(CI->getArgOperand(2), B, DL, TLI);<br>
> - if (!Len)<br>
> - return nullptr;<br>
> - Value *IncLen =<br>
> - B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");<br>
> - B.CreateMemCpy(CI->getArgOperand(0), Align(1), CI->getArgOperand(2),<br>
> - Align(1), IncLen);<br>
> -<br>
> - // The sprintf result is the unincremented number of bytes in the string.<br>
> - return B.CreateIntCast(Len, CI->getType(), false);<br>
> + return emitStrCpy(CI->getArgOperand(0), CI->getArgOperand(2), B, TLI);<br>
> }<br>
> return nullptr;<br>
> }<br>
> <br>
> diff --git a/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll b/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll<br>
> index 51610698c244..e3cf763917a0 100644<br>
> --- a/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll<br>
> +++ b/llvm/test/Transforms/InstCombine/2010-05-30-memcpy-Struct.ll<br>
> @@ -1,3 +1,4 @@<br>
> +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py<br>
> ; RUN: opt -instcombine -S < %s | FileCheck %s<br>
> ; PR7265<br>
> <br>
> @@ -9,10 +10,14 @@ target triple = "x86_64-unknown-linux-gnu"<br>
> @.str = private constant [3 x i8] c"%s\00"<br>
> <br>
> define void @CopyEventArg(%union.anon* %ev) nounwind {<br>
> +; CHECK-LABEL: @CopyEventArg(<br>
> +; CHECK-NEXT: entry:<br>
> +; CHECK-NEXT: [[CSTR:%.*]] = bitcast %union.anon* [[EV:%.*]] to i8*<br>
> +; CHECK-NEXT: [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) undef, i8* nonnull dereferenceable(1) [[CSTR]])<br>
> +; CHECK-NEXT: ret void<br>
> +;<br>
> entry:<br>
> %call = call i32 (i8*, i8*, ...) @sprintf(i8* undef, i8* getelementptr inbounds ([3 x i8], [3 x i8]* @.str, i64 0, i64 0), %union.anon* %ev) nounwind<br>
> -; CHECK: bitcast %union.anon* %ev to i8*<br>
> -; CHECK: call void @llvm.memcpy.p0i8.p0i8.i64<br>
> ret void<br>
> }<br>
> <br>
> <br>
> diff --git a/llvm/test/Transforms/InstCombine/sprintf-1.ll b/llvm/test/Transforms/InstCombine/sprintf-1.ll<br>
> index 9dbfecaecb31..77c2d4bbd9b6 100644<br>
> --- a/llvm/test/Transforms/InstCombine/sprintf-1.ll<br>
> +++ b/llvm/test/Transforms/InstCombine/sprintf-1.ll<br>
> @@ -81,19 +81,15 @@ define void @test_simplify4(i8* %dst) {<br>
> ret void<br>
> }<br>
> <br>
> -; Check sprintf(dst, "%s", str) -> llvm.memcpy(dest, str, strlen(str) + 1, 1).<br>
> +; Check sprintf(dst, "%s", str) -> strcpy(dst, str)<br>
> <br>
> define void @test_simplify5(i8* %dst, i8* %str) {<br>
> ; CHECK-LABEL: @test_simplify5(<br>
> -; CHECK-NEXT: [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])<br>
> -; CHECK-NEXT: [[LENINC:%.*]] = add i32 [[STRLEN]], 1<br>
> -; CHECK-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)<br>
> +; CHECK-NEXT: [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) [[STR:%.*]])<br>
> ; CHECK-NEXT: ret void<br>
> ;<br>
> ; CHECK-IPRINTF-LABEL: @test_simplify5(<br>
> -; CHECK-IPRINTF-NEXT: [[STRLEN:%.*]] = call i32 @strlen(i8* nonnull dereferenceable(1) [[STR:%.*]])<br>
> -; CHECK-IPRINTF-NEXT: [[LENINC:%.*]] = add i32 [[STRLEN]], 1<br>
> -; CHECK-IPRINTF-NEXT: call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 1 [[DST:%.*]], i8* align 1 [[STR]], i32 [[LENINC]], i1 false)<br>
> +; CHECK-IPRINTF-NEXT: [[STRCPY:%.*]] = call i8* @strcpy(i8* nonnull dereferenceable(1) [[DST:%.*]], i8* nonnull dereferenceable(1) [[STR:%.*]])<br>
> ; CHECK-IPRINTF-NEXT: ret void<br>
> ;<br>
> %fmt = getelementptr [3 x i8], [3 x i8]* @percent_s, i32 0, i32 0<br>
> <br>
> <br>
> <br>
> _______________________________________________<br>
> llvm-commits mailing list<br>
> <a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a><br>
> <a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits" rel="noreferrer" target="_blank">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits</a><br>
_______________________________________________<br>
llvm-commits mailing list<br>
<a href="mailto:llvm-commits@lists.llvm.org" target="_blank">llvm-commits@lists.llvm.org</a><br>
<a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits" rel="noreferrer" target="_blank">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits</a><br>
</blockquote></div>