Add a bit to mark operands of asm's that conflict

with an earlyclobber operand elsewhere.  Propagate
this bit and the earlyclobber bit through SDISel.
Change linear-scan RA not to allocate regs in a way 
that conflicts with an earlyclobber.  See also comments.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56290 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 22 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h
index c77513ca98..31eadcf7f8 100644
--- a/include/llvm/CodeGen/LiveIntervalAnalysis.h
+++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h
@@ -28,6 +28,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/Allocator.h"
 #include <cmath>
+#include <map>
 
 namespace llvm {
 
@@ -64,6 +65,22 @@ namespace llvm {
     AliasAnalysis *aa_;
     LiveVariables* lv_;
 
+    /// AsmsWithEarlyClobber - maps a virtual register number to all the
+    /// inline asm's that have the register marked earlyclobber.
+    /// 
+    std::multimap<unsigned, MachineInstr*> AsmsThatEarlyClobber;
+
+    /// AsmsWithEarlyClobberConflict - maps a virtual register number
+    /// to all the inline asm's that have earlyclobber operands elsewhere
+    /// and use the register as a (non-earlyclobber) input.
+    ///
+    /// Note: earlyclobber operands may not be assigned the same register as
+    /// each other, or as earlyclobber-conflict operands.  However two
+    /// earlyclobber-conflict operands may be assigned the same register if
+    /// they happen to contain the same value.
+    /// 
+    std::multimap<unsigned, MachineInstr*> AsmsWithEarlyClobberConflict;
+
     /// Special pool allocator for VNInfo's (LiveInterval val#).
     ///
     BumpPtrAllocator VNInfoAllocator;
@@ -336,6 +353,11 @@ namespace llvm {
     unsigned getNumConflictsWithPhysReg(const LiveInterval &li,
                                         unsigned PhysReg) const;
 
+    /// noEarlyclobberConflict - see whether virtual reg VReg has a conflict
+    /// with hard reg HReg because HReg is used as an earlyclobber register in
+    /// asm that also has VReg live into or across it.
+    bool noEarlyclobberConflict(unsigned VReg, VirtRegMap &vrm, unsigned HReg);
+
     /// computeNumbering - Compute the index numbering.
     void computeNumbering();