Test commit

[oota-llvm.git] / lib / Target / Mips / MSA.txt

diff --git a/lib/Target/Mips/MSA.txt b/lib/Target/Mips/MSA.txt
index 270a723048e8bd87e34a5d74ce1e67f932b998b9..cc934263287bc33aab0d85e0da0477c4a720d303 100644 (file)
--- a/lib/Target/Mips/MSA.txt
+++ b/lib/Target/Mips/MSA.txt
@@ -14,6 +14,11 @@ This section describes any quirks of instruction selection for MSA. For
 example, two instructions might be equally valid for some given IR and one is
 chosen in preference to the other.
 
+bclri.b:
+        It is not possible to emit bclri.b since andi.b covers exactly the
+        same cases. andi.b should use fractionally less power than bclri.b in
+        most hardware implementations so it is used in preference to bclri.b.
+
 vshf.w:
         It is not possible to emit vshf.w when the shuffle description is
         constant since shf.w covers exactly the same cases. shf.w is used
@@ -57,11 +62,16 @@ binsri.[bhwd],  binsli.[bhwd]:
 
 bmnz.v, bmz.v, bsel.v:
         These three operations differ only in the operand that is tied to the
-        result.
+        result and the order of the operands.
         It is (currently) not possible to emit bmz.v, or bsel.v since bmnz.v is
         the same operation and will be emitted instead.
         In future, the compiler may choose between these three instructions
         according to register allocation.
+        These three operations can be very confusing so here is a mapping
+        between the instructions and the vselect node in one place:
+                bmz.v  wd, ws, wt/i8 -> (vselect wt/i8, wd, ws)
+                bmnz.v wd, ws, wt/i8 -> (vselect wt/i8, ws, wd)
+                bsel.v wd, ws, wt/i8 -> (vselect wd, wt/i8, ws)
 
 bmnzi.b, bmzi.b:
         Like their non-immediate counterparts, bmnzi.v and bmzi.v are the same
@@ -71,3 +81,4 @@ bmnzi.b, bmzi.b:
 bseli.v:
         Unlike the non-immediate versions, bseli.v is distinguishable from
         bmnzi.b and bmzi.b and can be emitted.
+