CodeGen: Make folds User/DefinerOfRegs INLINEABLE.

Reduces allocation for the test case I was looking at by about 1.2%.
Mostly from avoiding allocation of some folding functions which turn
into let-no-escape bindings which just reuse their environment instead.

We also force inlining in a few key places in CmmSink which helps a bit
more.

2 files changed, 7 insertions, 0 deletions

diff --git a/compiler/GHC/Cmm/Expr.hs b/compiler/GHC/Cmm/Expr.hs
index e1251c6c27..ab613192ba 100644
--- a/compiler/GHC/Cmm/Expr.hs
+++ b/compiler/GHC/Cmm/Expr.hs
@@ -363,6 +363,7 @@ instance DefinerOfRegs LocalReg CmmReg where
     foldRegsDefd _ _ z (CmmGlobal _)  = z
 
 instance UserOfRegs GlobalReg CmmReg where
+    {-# INLINEABLE foldRegsUsed #-}
     foldRegsUsed _ _ z (CmmLocal _)    = z
     foldRegsUsed _ f z (CmmGlobal reg) = f z reg
 
@@ -379,6 +380,7 @@ instance Ord r => DefinerOfRegs r r where
 instance (Ord r, UserOfRegs r CmmReg) => UserOfRegs r CmmExpr where
   -- The (Ord r) in the context is necessary here
   -- See Note [Recursive superclasses] in GHC.Tc.TyCl.Instance
+  {-# INLINEABLE foldRegsUsed #-}
   foldRegsUsed platform f !z e = expr z e
     where expr z (CmmLit _)          = z
           expr z (CmmLoad addr _)    = foldRegsUsed platform f z addr
diff --git a/compiler/GHC/Cmm/Node.hs b/compiler/GHC/Cmm/Node.hs
index 61b4030620..943efaa3fd 100644
--- a/compiler/GHC/Cmm/Node.hs
+++ b/compiler/GHC/Cmm/Node.hs
@@ -318,6 +318,7 @@ foreignTargetHints target
 -- Instances of register and slot users / definers
 
 instance UserOfRegs LocalReg (CmmNode e x) where
+  {-# INLINEABLE foldRegsUsed #-}
   foldRegsUsed platform f !z n = case n of
     CmmAssign _ expr -> fold f z expr
     CmmStore addr rval -> fold f (fold f z addr) rval
@@ -332,6 +333,7 @@ instance UserOfRegs LocalReg (CmmNode e x) where
           fold f z n = foldRegsUsed platform f z n
 
 instance UserOfRegs GlobalReg (CmmNode e x) where
+  {-# INLINEABLE foldRegsUsed #-}
   foldRegsUsed platform f !z n = case n of
     CmmAssign _ expr -> fold f z expr
     CmmStore addr rval -> fold f (fold f z addr) rval
@@ -348,10 +350,12 @@ instance UserOfRegs GlobalReg (CmmNode e x) where
 instance (Ord r, UserOfRegs r CmmReg) => UserOfRegs r ForeignTarget where
   -- The (Ord r) in the context is necessary here
   -- See Note [Recursive superclasses] in GHC.Tc.TyCl.Instance
+  {-# INLINEABLE foldRegsUsed #-}
   foldRegsUsed _        _ !z (PrimTarget _)      = z
   foldRegsUsed platform f !z (ForeignTarget e _) = foldRegsUsed platform f z e
 
 instance DefinerOfRegs LocalReg (CmmNode e x) where
+  {-# INLINEABLE foldRegsDefd #-}
   foldRegsDefd platform f !z n = case n of
     CmmAssign lhs _ -> fold f z lhs
     CmmUnsafeForeignCall _ fs _ -> fold f z fs
@@ -362,6 +366,7 @@ instance DefinerOfRegs LocalReg (CmmNode e x) where
           fold f z n = foldRegsDefd platform f z n
 
 instance DefinerOfRegs GlobalReg (CmmNode e x) where
+  {-# INLINEABLE foldRegsDefd #-}
   foldRegsDefd platform f !z n = case n of
     CmmAssign lhs _ -> fold f z lhs
     CmmUnsafeForeignCall tgt _ _  -> fold f z (foreignTargetRegs tgt)