Issue description:

SchedulerDAGInstrs::buildSchedGraph ignores dependencies between FixedStack
objects and byval parameters. So loading byval parameters from stack may be
inserted *before* it will be stored, since these operations are treated as
independent.

Fix:
Currently ARMTargetLowering::LowerFormalArguments saves byval registers with
FixedStack MachinePointerInfo. To fix the problem we need to store byval
registers with MachinePointerInfo referenced to first the "byval" parameter.

Also commit adds two new fields to the InputArg structure: Function's argument
index and InputArg's part offset in bytes relative to the start position of
Function's argument. E.g.: If function's argument is 128 bit width and it was
splitted onto 32 bit regs, then we got 4 InputArg structs with same arg index,
but different offset values. 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165616 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 2 deletions

diff --git a/include/llvm/Target/TargetCallingConv.h b/include/llvm/Target/TargetCallingConv.h
index f8cebefb0ea..8030d38d738 100644
--- a/include/llvm/Target/TargetCallingConv.h
+++ b/include/llvm/Target/TargetCallingConv.h
@@ -113,9 +113,18 @@ namespace ISD {
     MVT VT;
     bool Used;
 
+    /// Index original Function's argument.
+    unsigned OrigArgIndex;
+
+    /// Offset in bytes of current input value relative to the beginning of
+    /// original argument. E.g. if argument was splitted into four 32 bit
+    /// registers, we got 4 InputArgs with PartOffsets 0, 4, 8 and 12.
+    unsigned PartOffset;
+
     InputArg() : VT(MVT::Other), Used(false) {}
-    InputArg(ArgFlagsTy flags, EVT vt, bool used)
-      : Flags(flags), Used(used) {
+    InputArg(ArgFlagsTy flags, EVT vt, bool used,
+             unsigned origIdx, unsigned partOffs)
+      : Flags(flags), Used(used), OrigArgIndex(origIdx), PartOffset(partOffs) {
       VT = vt.getSimpleVT();
     }
   };