vendor/llvm/llvm-release_50-r310316

1 files changed, 9 insertions, 2 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index ba8eb8656585a..7563bffd8f873 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3984,6 +3984,13 @@ bool MatchingStackOffset(SDValue Arg, unsigned Offset, ISD::ArgFlagsTy Flags,
   if (Offset != MFI.getObjectOffset(FI))
     return false;
 
+  // If this is not byval, check that the argument stack object is immutable.
+  // inalloca and argument copy elision can create mutable argument stack
+  // objects. Byval objects can be mutated, but a byval call intends to pass the
+  // mutated memory.
+  if (!Flags.isByVal() && !MFI.isImmutableObjectIndex(FI))
+    return false;
+
   if (VA.getLocVT().getSizeInBits() > Arg.getValueSizeInBits()) {
     // If the argument location is wider than the argument type, check that any
     // extension flags match.
@@ -30605,8 +30612,8 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG,
     assert(BitWidth >= 8 && BitWidth <= 64 && "Invalid mask size");
     APInt DemandedMask(APInt::getSignMask(BitWidth));
     KnownBits Known;
-    TargetLowering::TargetLoweringOpt TLO(DAG, DCI.isBeforeLegalize(),
-                                          DCI.isBeforeLegalizeOps());
+    TargetLowering::TargetLoweringOpt TLO(DAG, !DCI.isBeforeLegalize(),
+                                          !DCI.isBeforeLegalizeOps());
     if (TLI.ShrinkDemandedConstant(Cond, DemandedMask, TLO) ||
         TLI.SimplifyDemandedBits(Cond, DemandedMask, Known, TLO)) {
       // If we changed the computation somewhere in the DAG, this change will