Commit a590c655 authored by Tanya Lattner's avatar Tanya Lattner
Browse files

Merge 81821 from mainline. 

Don't pull a load through a callseq_start if the load's chain
has multiple uses, as one of the other uses may be on a path
to a different node above the callseq_start, because that
leads to a cyclic graph. This problem is exposed when
-combiner-global-alias-analysis is used. This fixes PR4880.

llvm-svn: 81978
parent c61881e7

llvm/lib/Target/X86/X86ISelDAGToDAG.cpp

+2 −1
Original line number Diff line number Diff line
@@ -447,7 +447,8 @@ static bool isCalleeLoad(SDValue Callee, SDValue &Chain) { 
  if (Chain.getOperand(0).getNode() == Callee.getNode())

    return true;

  if (Chain.getOperand(0).getOpcode() == ISD::TokenFactor &&

      Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()))

      Callee.getValue(1).isOperandOf(Chain.getOperand(0).getNode()) &&

      Callee.getValue(1).hasOneUse())

    return true;

  return false;

}

llvm/test/CodeGen/X86/combiner-aa-1.ll

0 → 100644
+23 −0
Original line number Diff line number Diff line 
; RUN: llc < %s --combiner-alias-analysis --combiner-global-alias-analysis

; PR4880



target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"

target triple = "i386-pc-linux-gnu"



%struct.alst_node = type { %struct.node }

%struct.arg_node = type { %struct.node, i8*, %struct.alst_node* }

%struct.arglst_node = type { %struct.alst_node, %struct.arg_node*, %struct.arglst_node* }

%struct.lam_node = type { %struct.alst_node, %struct.arg_node*, %struct.alst_node* }

%struct.node = type { i32 (...)**, %struct.node* }



define i32 @._ZN8lam_node18resolve_name_clashEP8arg_nodeP9alst_node._ZNK8lam_nodeeqERK8exp_node._ZN11arglst_nodeD0Ev(%struct.lam_node* %this.this, %struct.arg_node* %outer_arg, %struct.alst_node* %env.cmp, %struct.arglst_node* %this, i32 %functionID) {

comb_entry:

  %.SV59 = alloca %struct.node*                   ; <%struct.node**> [#uses=1]

  %0 = load i32 (...)*** null, align 4            ; <i32 (...)**> [#uses=1]

  %1 = getelementptr inbounds i32 (...)** %0, i32 3 ; <i32 (...)**> [#uses=1]

  %2 = load i32 (...)** %1, align 4               ; <i32 (...)*> [#uses=1]

  store %struct.node* undef, %struct.node** %.SV59

  %3 = bitcast i32 (...)* %2 to i32 (%struct.node*)* ; <i32 (%struct.node*)*> [#uses=1]

  %4 = tail call i32 %3(%struct.node* undef)      ; <i32> [#uses=0]

  unreachable

}