[Hexagon] Allow setting register in BitVal without storing into map

In the bit tracker, references to other bit values in which the register
is 0 are prohibited. This means that generating self-referential register
cells like { w:32 [0-15]:s[0-15] [16-31]:s[15] } is impossible. In order
to get a self-referential cell, it had to be stored into a map and then
reloaded from it. To avoid this step, add a function that will set the
register to a given value without going through the map.

llvm-svn: 296025

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/Target/Hexagon/BitTracker.h b/llvm/lib/Target/Hexagon/BitTracker.h
index 48c5f2266ac..a547b34e852 100644
--- a/llvm/lib/Target/Hexagon/BitTracker.h
+++ b/llvm/lib/Target/Hexagon/BitTracker.h
@@ -283,6 +283,9 @@ struct BitTracker::RegisterCell {
     return !operator==(RC);
   }
 
+  // Replace the ref-to-reg-0 bit values with the given register.
+  RegisterCell &regify(unsigned R);
+
   // Generate a "ref" cell for the corresponding register. In the resulting
   // cell each bit will be described as being the same as the corresponding
   // bit in register Reg (i.e. the cell is "defined" by register Reg).