[llvm] r348574 - [SelectionDAG] Don't pass on DemandedElts when handling SCALAR_TO_VECTOR

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Fri Dec  7 01:18:44 2018
New Revision: 348574

URL: http://llvm.org/viewvc/llvm-project?rev=348574&view=rev
Log:
[SelectionDAG] Don't pass on DemandedElts when handling SCALAR_TO_VECTOR

Fixes an assertion:

llc: lib/CodeGen/SelectionDAG/SelectionDAG.cpp:2200: llvm::KnownBits llvm::SelectionDAG::computeKnownBits(llvm::SDValue, const llvm::APInt&, unsigned int) const: Assertion `(!Op.getValueType().isVector() || NumElts == Op.getValueType().getVectorNumElements()) && "Unexpected vector size"' failed.

Committed on behalf of: @pendingchaos (Rhys Perry)

Differential Revision: https://reviews.llvm.org/D55223

Added:
    llvm/trunk/test/CodeGen/AMDGPU/computeKnownBits-scalar-to-vector-crash.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp?rev=348574&r1=348573&r2=348574&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAG.cpp Fri Dec  7 01:18:44 2018
@@ -2352,7 +2352,7 @@ KnownBits SelectionDAG::computeKnownBits
       break;
 
     SDValue N0 = Op.getOperand(0);
-    Known = computeKnownBits(N0, DemandedElts, Depth + 1);
+    Known = computeKnownBits(N0, Depth + 1);
     if (N0.getValueSizeInBits() != BitWidth)
       Known = Known.trunc(BitWidth);
 

Added: llvm/trunk/test/CodeGen/AMDGPU/computeKnownBits-scalar-to-vector-crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AMDGPU/computeKnownBits-scalar-to-vector-crash.ll?rev=348574&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AMDGPU/computeKnownBits-scalar-to-vector-crash.ll (added)
+++ llvm/trunk/test/CodeGen/AMDGPU/computeKnownBits-scalar-to-vector-crash.ll Fri Dec  7 01:18:44 2018
@@ -0,0 +1,11 @@
+; RUN: llc -march=amdgcn -mcpu=gfx802 -verify-machineinstrs < %s | FileCheck %s
+
+; CHECK: s_waitcnt
+define <2 x i16> @main(<2 x float>) #0 {
+  %2 = bitcast <2 x float> %0 to <4 x i16>
+  %3 = shufflevector <4 x i16> %2, <4 x i16> undef, <2 x i32> <i32 0, i32 undef>
+  %4 = extractelement <4 x i16> %2, i32 0
+  %5 = insertelement <2 x i16> %3, i16 %4, i32 0
+  ret <2 x i16> %5
+}
+