[X86] Relax an assertion when legalizing vector types.

WidenVSELECTAndMask can fold (and it folds in this case) so we
get a BUILD_VECTOR of constants as mask. convertMask() seems to
work fine when the input is a vector of constants, and we still
need to call it to extend/add elements at the end. but the current
code just asserts on anything but a SETCC or AND/OR/XOR of 2xSETCC.
This change was discussed briefly with Simon Pilgrim, who also
suggests we might consider dropping this assertion in the future.

Fixes PR33715.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@307508 91177308-0d34-0410-b5e6-96231b3b80d8

Author: dcci

lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

@@ -2977,7 +2977,11 @@ SDValue DAGTypeLegalizer::convertMask(SDValue InMask, EVT MaskVT,
 
   // Currently a SETCC or a AND/OR/XOR with two SETCCs are handled.
   unsigned InMaskOpc = InMask->getOpcode();
+
+  // FIXME: This code seems to be too restrictive, we might consider
+  // generalizing it or dropping it.
   assert((InMaskOpc == ISD::SETCC ||
+          ISD::isBuildVectorOfConstantSDNodes(InMask.getNode()) ||
           (isLogicalMaskOp(InMaskOpc) &&
            isSETCCorConvertedSETCC(InMask->getOperand(0)) &&
            isSETCCorConvertedSETCC(InMask->getOperand(1)))) &&

test/CodeGen/X86/pr33715.ll

@@ -0,0 +1,16 @@
+; Make sure we don't crash with a build vector of integer constants.
+; RUN: llc %s -o /dev/null
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @patatino() {
+  %tmp = insertelement <4 x i32> <i32 1, i32 1, i32 undef, i32 undef>, i32 1, i32 2
+  %tmp1 = insertelement <4 x i32> %tmp, i32 1, i32 3
+  %tmp2 = icmp ne <4 x i32> %tmp1, zeroinitializer
+  %tmp3 = icmp slt <4 x i32> %tmp1, <i32 4, i32 4, i32 4, i32 4>
+  %tmp4 = or <4 x i1> %tmp2, %tmp3
+  %tmp5 = select <4 x i1> %tmp4, <4 x i32> zeroinitializer, <4 x i32> <i32 4, i32 4, i32 4, i32 4>
+  %tmp6 = extractelement <4 x i32> %tmp5, i32 0
+  ret i32 %tmp6
+}