<div dir="ltr">No, this is not a regression; the oldest LLVM I have, 3.4, fails with the exact same test case. Trunk has a more comprehensive series of commits which really fix this bug.</div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Aug 1, 2016 at 1:38 PM, Hans Wennborg <span dir="ltr"><<a href="mailto:hans@chromium.org" target="_blank">hans@chromium.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Ping?<br>
<div class="HOEnZb"><div class="h5"><br>
On Thu, Jul 28, 2016 at 9:00 AM, Hans Wennborg <<a href="mailto:hans@chromium.org">hans@chromium.org</a>> wrote:<br>
> Should this be merged to 3.9?<br>
><br>
> Cheers,<br>
> Hans<br>
><br>
> On Tue, Jul 26, 2016 at 7:39 PM, David Majnemer via llvm-commits<br>
> <<a href="mailto:llvm-commits@lists.llvm.org">llvm-commits@lists.llvm.org</a>> wrote:<br>
>> Author: majnemer<br>
>> Date: Tue Jul 26 21:39:16 2016<br>
>> New Revision: 276827<br>
>><br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project?rev=276827&view=rev" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project?rev=276827&view=rev</a><br>
>> Log:<br>
>> [ConstantFolding] Correctly handle failures in ConstantFoldConstantExpressionImpl<br>
>><br>
>> Failures in ConstantFoldConstantExpressionImpl were ignored causing<br>
>> crashes down the line.<br>
>><br>
>> This fixes PR28725.<br>
>><br>
>> Added:<br>
>> llvm/trunk/test/Transforms/InstSimplify/pr28725.ll<br>
>> Modified:<br>
>> llvm/trunk/lib/Analysis/ConstantFolding.cpp<br>
>><br>
>> Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp<br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=276827&r1=276826&r2=276827&view=diff" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=276827&r1=276826&r2=276827&view=diff</a><br>
>> ==============================================================================<br>
>> --- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)<br>
>> +++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Tue Jul 26 21:39:16 2016<br>
>> @@ -1007,8 +1007,12 @@ Constant *llvm::ConstantFoldInstruction(<br>
>> for (const Use &OpU : I->operands()) {<br>
>> auto *Op = cast<Constant>(&OpU);<br>
>> // Fold the Instruction's operands.<br>
>> - if (auto *NewCE = dyn_cast<ConstantExpr>(Op))<br>
>> - Op = ConstantFoldConstantExpression(NewCE, DL, TLI);<br>
>> + if (auto *NewCE = dyn_cast<ConstantExpr>(Op)) {<br>
>> + auto *FoldedOp = ConstantFoldConstantExpression(NewCE, DL, TLI);<br>
>> + if (!FoldedOp)<br>
>> + return nullptr;<br>
>> + Op = FoldedOp;<br>
>> + }<br>
>><br>
>> Ops.push_back(Op);<br>
>> }<br>
>> @@ -1048,8 +1052,13 @@ ConstantFoldConstantExpressionImpl(const<br>
>> // Recursively fold the ConstantExpr's operands. If we have already folded<br>
>> // a ConstantExpr, we don't have to process it again.<br>
>> if (auto *NewCE = dyn_cast<ConstantExpr>(NewC)) {<br>
>> - if (FoldedOps.insert(NewCE).second)<br>
>> - NewC = ConstantFoldConstantExpressionImpl(NewCE, DL, TLI, FoldedOps);<br>
>> + if (FoldedOps.insert(NewCE).second){<br>
>> + auto *FoldedC =<br>
>> + ConstantFoldConstantExpressionImpl(NewCE, DL, TLI, FoldedOps);<br>
>> + if (!FoldedC)<br>
>> + return nullptr;<br>
>> + NewC = FoldedC;<br>
>> + }<br>
>> }<br>
>> Ops.push_back(NewC);<br>
>> }<br>
>><br>
>> Added: llvm/trunk/test/Transforms/InstSimplify/pr28725.ll<br>
>> URL: <a href="http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/pr28725.ll?rev=276827&view=auto" rel="noreferrer" target="_blank">http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/pr28725.ll?rev=276827&view=auto</a><br>
>> ==============================================================================<br>
>> --- llvm/trunk/test/Transforms/InstSimplify/pr28725.ll (added)<br>
>> +++ llvm/trunk/test/Transforms/InstSimplify/pr28725.ll Tue Jul 26 21:39:16 2016<br>
>> @@ -0,0 +1,14 @@<br>
>> +; RUN: opt -S -instsimplify < %s | FileCheck %s<br>
>> +target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"<br>
>> +target triple = "x86_64-pc-windows-msvc"<br>
>> +%S = type { i16, i32 }<br>
>> +<br>
>> +define <2 x i16> @test1() {<br>
>> +entry:<br>
>> + %b = insertelement <2 x i16> <i16 undef, i16 0>, i16 extractvalue (%S select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), %S zeroinitializer, %S { i16 0, i32 1 }), 0), i32 0<br>
>> + ret <2 x i16> %b<br>
>> +}<br>
>> +<br>
>> +; CHECK-LABEL: @test1(<br>
>> +; CHECK: %[[ie:.*]] = insertelement <2 x i16> <i16 undef, i16 0>, i16 extractvalue (%S select (i1 icmp eq (i16 extractelement (<2 x i16> bitcast (<1 x i32> <i32 1> to <2 x i16>), i32 0), i16 0), %S zeroinitializer, %S { i16 0, i32 1 }), 0), i32 0<br>
>> +; CHECK: ret <2 x i16> %[[ie]]<br>
>><br>
>><br>
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</div></div></blockquote></div><br></div>