[llvm] r234763 - DAGCombiner: Fix crash in select(select) opt.

[Quentin Colombet]

Hi Matthias,


> On Apr 13, 2015, at 10:16 AM, Matthias Braun <matze at braunis.de> wrote:
> 
> Author: matze
> Date: Mon Apr 13 12:16:33 2015
> New Revision: 234763
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=234763&view=rev
> Log:
> DAGCombiner: Fix crash in select(select) opt.
> 
> In case of different types used for the condition of the selects the
> select(select) -> select(and) normalisation cannot be performed.
> 
> See also: http://reviews.llvm.org/D7622
> 
> Added:
>    llvm/trunk/test/CodeGen/Mips/dagcombine_crash.ll
> Modified:
>    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> 
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=234763&r1=234762&r2=234763&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Apr 13 12:16:33 2015
> @@ -4881,7 +4881,7 @@ SDValue DAGCombiner::visitSELECT(SDNode
>       SDValue N1_0 = N1->getOperand(0);
>       SDValue N1_1 = N1->getOperand(1);
>       SDValue N1_2 = N1->getOperand(2);
> -      if (N1_2 == N2) {
> +      if (N1_2 == N2 && N0.getValueType() == N1_0.getValueType()) {
>         // Create the actual and node if we can generate good code for it.
>         if (!TLI.shouldNormalizeToSelectSequence(*DAG.getContext(), VT)) {
>           SDValue And = DAG.getNode(ISD::AND, SDLoc(N), N0.getValueType(),
> @@ -4900,7 +4900,7 @@ SDValue DAGCombiner::visitSELECT(SDNode
>       SDValue N2_0 = N2->getOperand(0);
>       SDValue N2_1 = N2->getOperand(1);
>       SDValue N2_2 = N2->getOperand(2);
> -      if (N2_1 == N1) {
> +      if (N2_1 == N1 && N0.getValueType() == N2_0.getValueType()) {
>         // Create the actual or node if we can generate good code for it.
>         if (!TLI.shouldNormalizeToSelectSequence(*DAG.getContext(), VT)) {
>           SDValue Or = DAG.getNode(ISD::OR, SDLoc(N), N0.getValueType(),
> 
> Added: llvm/trunk/test/CodeGen/Mips/dagcombine_crash.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Mips/dagcombine_crash.ll?rev=234763&view=auto
> ==============================================================================
> --- llvm/trunk/test/CodeGen/Mips/dagcombine_crash.ll (added)
> +++ llvm/trunk/test/CodeGen/Mips/dagcombine_crash.ll Mon Apr 13 12:16:33 2015
> @@ -0,0 +1,21 @@
> +; RUN: llc -o - %s

Please add some, even trivial, check lines.

Thanks,
-Quentin

> +; The selection DAG select(select()) normalisation crashed for different types
> +; on the condition inputs.
> +target datalayout = "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"
> +target triple = "mips--"
> +
> +define i64 @foobar(double %a) #0 {
> +entry:
> +  %0 = bitcast double %a to i64
> +  %trunc = trunc i64 %0 to i32
> +  %and = and i32 %trunc, 32767
> +  %sub = add nsw i32 %and, -16383
> +  %cmp = icmp ugt i32 %and, 16382
> +  %and5 = and i32 %trunc, 32768
> +  %tobool = icmp eq i32 %and5, 0
> +  %or = and i1 %cmp, %tobool
> +  %cmp6 = icmp ugt i32 %sub, 64
> +  %sext = sext i1 %cmp6 to i64
> +  %retval.0 = select i1 %or, i64 %sext, i64 0
> +  ret i64 %retval.0
> +}
> 
> 
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