Allow C argument regs to be used as global regs (R1, R2, etc.)

[ghc-hetmet.git] / ghc / compiler / cmm / CmmOpt.hs

diff --git a/ghc/compiler/cmm/CmmOpt.hs b/ghc/compiler/cmm/CmmOpt.hs
index 95d1318..c8d48b4 100644 (file)
--- a/ghc/compiler/cmm/CmmOpt.hs
+++ b/ghc/compiler/cmm/CmmOpt.hs
@@ -15,6 +15,7 @@ module CmmOpt (
 #include "HsVersions.h"
 
 import Cmm
+import CmmUtils        ( hasNoGlobalRegs )
 import CLabel  ( entryLblToInfoLbl )
 import MachOp
 import SMRep   ( tablesNextToCode )
@@ -85,8 +86,17 @@ lookForInline u expr (CmmNop : rest)
 
 lookForInline u expr (stmt:stmts)
   = case lookupUFM (getStmtUses stmt) u of
-       Just 1 -> Just (inlineStmt u expr stmt : stmts)
+       Just 1 | ok_to_inline -> Just (inlineStmt u expr stmt : stmts)
        _other -> Nothing
+  where
+       -- we don't inline into CmmCall if the expression refers to global
+       -- registers.  This is a HACK to avoid global registers clashing with
+       -- C argument-passing registers, really the back-end ought to be able
+       -- to handle it properly, but currently neither PprC nor the NCG can
+       -- do it.  See also CgForeignCall:load_args_into_temps.
+    ok_to_inline = case stmt of
+                    CmmCall{} -> hasNoGlobalRegs expr
+                    _ -> True
 
 -- -----------------------------------------------------------------------------
 -- Boring Cmm traversals for collecting usage info and substitutions.