[project @ 2005-02-01 15:08:06 by simonmar]

small perf hack in emitVectoredReturnInstr: work around lack of CSE in
the NCG by assigning info_amode to a new temporary.

diff --git a/ghc/compiler/codeGen/CgInfoTbls.hs b/ghc/compiler/codeGen/CgInfoTbls.hs
index 7692e7d..981b4b0 100644 (file)
--- a/ghc/compiler/codeGen/CgInfoTbls.hs
+++ b/ghc/compiler/codeGen/CgInfoTbls.hs
@@ -44,7 +44,8 @@ import CgCallConv     ( isBigLiveness, mkLivenessCLit, buildContLiveness,
                          CtrlReturnConvention(..) )
 import CgUtils         ( mkStringCLit, packHalfWordsCLit, mkWordCLit, 
                          cmmOffsetB, cmmOffsetExprW, cmmLabelOffW, cmmOffsetW,
-                         emitDataLits, emitRODataLits, emitSwitch, cmmNegate )
+                         emitDataLits, emitRODataLits, emitSwitch, cmmNegate,
+                         newTemp )
 import CgMonad
 
 import CmmUtils                ( mkIntCLit, zeroCLit )
@@ -348,7 +349,11 @@ emitVectoredReturnInstr :: CmmExpr -- *Zero-indexed* constructor tag
                        -> Code
 emitVectoredReturnInstr zero_indexed_tag
   = do { info_amode <- getSequelAmode
-       ; let target = retVec info_amode zero_indexed_tag
+               -- HACK! assign info_amode to a temp, because retVec
+               -- uses it twice and the NCG doesn't have any CSE yet.
+       ; x <- newTemp wordRep
+       ; stmtC (CmmAssign x info_amode)
+       ; let target = retVec (CmmReg x) zero_indexed_tag
        ; stmtC (CmmJump target []) }