[llvm] r347227 - [SelectionDAG] simplify vector select with undef operand(s)
Jordan Rupprecht via llvm-commits
llvm-commits at lists.llvm.org
Wed Nov 28 12:57:51 PST 2018
Looks like this is causing llvm to crash with msan + opt. Here's a test
case courtesy of creduce:
$ cat repro.cc
float a, b, c, d, e;
void f(float *j, float *k) {
float g(a ? b * (1.0f - c) : b * (1.0f + c));
float h(a ? (1.0f - b) * (1.0f + c) : (1.0f - b) * c);
*j = g * 0;
*k = h * 0;
}
float *i;
void l() {
float m = 0, n = 0;
f(&d, &e);
m *= d;
n *= e;
i[0] = i[1] = m;
i[2] = i[3] = n;
}
$ ~/path/to/clang++ -fsanitize=memory -msse4.2 -O2 -c repro.cc
fatal error: error in backend: Cannot select: t389: v2i64 = bitcast t388
t388: v4i32 = X86ISD::PSHUFD t387, Constant:i8<68>
t387: v4i32 = bitcast t266
t266: v2i64 = scalar_to_vector t216
t216: i64,ch = load<(load 4 from `i32* inttoptr (i64 xor (i64
ptrtoint (float* @c to i64), i64 87960930222080) to i32*)`), anyext from
i32> t0, t20, undef:i64
t20: i64 = xor t317, Constant:i64<87960930222080>
t317: i64 = X86ISD::Wrapper TargetGlobalAddress:i64<float* @c> 0
t316: i64 = TargetGlobalAddress<float* @c> 0
t5: i64 = Constant<87960930222080>
t3: i64 = undef
t361: i8 = Constant<68>
In function: _Z1lv
clang-8: error: clang frontend command failed with exit code 70 (use -v to
see invocation)
clang version 8.0.0 (trunk 347216) (llvm/trunk 347227)
On Mon, Nov 19, 2018 at 9:08 AM Sanjay Patel via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: spatel
> Date: Mon Nov 19 09:06:05 2018
> New Revision: 347227
>
> URL: http://llvm.org/viewvc/llvm-project?rev=347227&view=rev
> Log:
> [SelectionDAG] simplify vector select with undef operand(s)
>
> Modified:
> llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
> llvm/trunk/test/CodeGen/X86/pr30284.ll
> llvm/trunk/test/CodeGen/X86/pr37499.ll
>
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=347227&r1=347226&r2=347227&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Nov 19
> 09:06:05 2018
> @@ -7816,9 +7816,8 @@ SDValue DAGCombiner::visitVSELECT(SDNode
> SDValue N2 = N->getOperand(2);
> SDLoc DL(N);
>
> - // fold (vselect C, X, X) -> X
> - if (N1 == N2)
> - return N1;
> + if (SDValue V = DAG.simplifySelect(N0, N1, N2))
> + return V;
>
> // Canonicalize integer abs.
> // vselect (setg[te] X, 0), X, -X ->
>
> Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=347227&r1=347226&r2=347227&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
> +++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Mon Nov 19
> 09:06:05 2018
> @@ -5078,6 +5078,7 @@ SDValue SelectionDAG::getNode(unsigned O
> break;
> }
> case ISD::SELECT:
> + case ISD::VSELECT:
> if (SDValue V = simplifySelect(N1, N2, N3))
> return V;
> break;
> @@ -6790,11 +6791,18 @@ SDValue SelectionDAG::simplifySelect(SDV
> if (F.isUndef())
> return T;
>
> - // fold (select true, T, F) -> T
> - // fold (select false, T, F) -> F
> + // select true, T, F --> T
> + // select false, T, F --> F
> if (auto *CondC = dyn_cast<ConstantSDNode>(Cond))
> return CondC->isNullValue() ? F : T;
>
> + // TODO: This should simplify VSELECT with constant condition using
> something
> + // like this (but check boolean contents to be complete?):
> + // if (ISD::isBuildVectorAllOnes(Cond.getNode()))
> + // return T;
> + // if (ISD::isBuildVectorAllZeros(Cond.getNode()))
> + // return F;
> +
> // select ?, T, T --> T
> if (T == F)
> return T;
>
> Modified: llvm/trunk/test/CodeGen/X86/pr30284.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr30284.ll?rev=347227&r1=347226&r2=347227&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/pr30284.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/pr30284.ll Mon Nov 19 09:06:05 2018
> @@ -4,14 +4,6 @@
> define void @undef_cond() {
> ; CHECK-LABEL: undef_cond:
> ; CHECK: # %bb.0:
> -; CHECK-NEXT: vmovapd 0, %zmm0
> -; CHECK-NEXT: vmovapd 64, %zmm1
> -; CHECK-NEXT: vmovapd {{.*#+}} zmm2 =
> [0,16,0,16,0,16,0,16,0,16,0,16,0,16,0,16]
> -; CHECK-NEXT: vorpd %zmm2, %zmm0, %zmm0 {%k1}
> -; CHECK-NEXT: vorpd %zmm2, %zmm1, %zmm1 {%k1}
> -; CHECK-NEXT: vmovapd %zmm1, 64
> -; CHECK-NEXT: vmovapd %zmm0, 0
> -; CHECK-NEXT: vzeroupper
> ; CHECK-NEXT: retl
> %a_load22 = load <16 x i64>, <16 x i64>* null, align 1
> %bitop = or <16 x i64> %a_load22, <i64 68719476736, i64 68719476736,
> i64 68719476736, i64 68719476736, i64 68719476736, i64 68719476736, i64
> 68719476736, i64 68719476736, i64 68719476736, i64 68719476736, i64
> 68719476736, i64 68719476736, i64 68719476736, i64 68719476736, i64
> 68719476736, i64 68719476736>
>
> Modified: llvm/trunk/test/CodeGen/X86/pr37499.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/pr37499.ll?rev=347227&r1=347226&r2=347227&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/pr37499.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/pr37499.ll Mon Nov 19 09:06:05 2018
> @@ -4,14 +4,7 @@
> define <2 x i64> @undef_tval() {
> ; CHECK-LABEL: undef_tval:
> ; CHECK: # %bb.0:
> -; CHECK-NEXT: vmovdqa {{.*#+}} xmm0 = [1,1,1,1,1,1,1,1]
> -; CHECK-NEXT: movb $1, %al
> -; CHECK-NEXT: kmovw %eax, %k1
> -; CHECK-NEXT: vpcmpeqd %ymm1, %ymm1, %ymm1
> -; CHECK-NEXT: vmovdqa32 %ymm1, %ymm1 {%k1} {z}
> -; CHECK-NEXT: vpmovdw %ymm1, %xmm1
> -; CHECK-NEXT: vpblendvb %xmm1, %xmm0, %xmm0, %xmm0
> -; CHECK-NEXT: vzeroupper
> +; CHECK-NEXT: vmovaps {{.*#+}} xmm0 = [1,1,1,1,1,1,1,1]
> ; CHECK-NEXT: retq
> %1 = tail call <8 x i16> @llvm.x86.avx512.mask.pmov.qw.512(<8 x i64>
> undef, <8 x i16> <i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1, i16 1>,
> i8 1) #3
> %2 = bitcast <8 x i16> %1 to <2 x i64>
>
>
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