From: Nadav Rotem <nadav.rotem@intel.com>
Date: Mon, 16 Jul 2012 18:34:53 +0000 (+0000)
Subject: Make ComputeDemandedBits return a deterministic result when computing an AssertZext... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=7ee0e5ae6093dba18ecc5eaafb91e8fa82f4c409;p=oota-llvm.git

Make ComputeDemandedBits return a deterministic result when computing an AssertZext value.
In the added testcase the constant 55 was behind an AssertZext of type i1, and ComputeDemandedBits
reported that some of the bits were both known to be one and known to be zero.

Together with Michael Kuperstein <michael.m.kuperstein@intel.com>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160305 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 3947648e6a7..cfe71708fe0 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1965,6 +1965,7 @@ void SelectionDAG::ComputeMaskedBits(SDValue Op, APInt &KnownZero,
     APInt InMask = APInt::getLowBitsSet(BitWidth, VT.getSizeInBits());
     ComputeMaskedBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
     KnownZero |= (~InMask);
+    KnownOne  &= (~KnownZero);
     return;
   }
   case ISD::FGETSIGN:
diff --git a/test/CodeGen/X86/2012-07-16-fp2ui-i1.ll b/test/CodeGen/X86/2012-07-16-fp2ui-i1.ll
new file mode 100644
index 00000000000..17533a1e164
--- /dev/null
+++ b/test/CodeGen/X86/2012-07-16-fp2ui-i1.ll
@@ -0,0 +1,12 @@
+; RUN: llc < %s -march=x86-64 -mcpu=corei7
+
+define void @autogen_SD3100() {
+BB:
+  %FC123 = fptoui float 0x40693F5D00000000 to i1
+  br i1 %FC123, label %V, label %W
+
+V:
+  ret void
+W:
+  ret void
+}