FIX #1910: fix code generated for GDTOI on x86_32

[ghc-hetmet.git] / compiler / nativeGen / PprMach.hs

diff --git a/compiler/nativeGen/PprMach.hs b/compiler/nativeGen/PprMach.hs
index dd3d029..26a6f28 100644 (file)
--- a/compiler/nativeGen/PprMach.hs
+++ b/compiler/nativeGen/PprMach.hs
@@ -1,3 +1,10 @@
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 -----------------------------------------------------------------------------
 --
 -- Pretty-printing assembly language
@@ -10,13 +17,6 @@
 -- (e.g., 'pprReg'); we conclude with the no-commonality monster,
 -- 'pprInstr'.
 
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
--- for details
-
 #include "nativeGen/NCG.h"
 
 module PprMach ( 
@@ -72,23 +72,19 @@ pprNatCmmTop (CmmProc [] lbl _ (ListGraph [])) = pprLabel lbl
 
 pprNatCmmTop (CmmProc info lbl params (ListGraph blocks)) = 
   pprSectionHeader Text $$
-  (if not (null info)
-       then
+  (if null info then -- blocks guaranteed not null, so label needed
+       pprLabel lbl
+   else
 #if HAVE_SUBSECTIONS_VIA_SYMBOLS
             pprCLabel_asm (mkDeadStripPreventer $ entryLblToInfoLbl lbl)
                 <> char ':' $$
 #endif
-            vcat (map pprData info) $$
-            pprLabel (entryLblToInfoLbl lbl)
-       else empty) $$
-  (case blocks of
-       [] -> empty
-       (BasicBlock _ instrs : rest) -> 
-               (if null info then pprLabel lbl else empty) $$
-               -- the first block doesn't get a label:
-               vcat (map pprInstr instrs) $$
-               vcat (map pprBasicBlock rest)
-  )
+       vcat (map pprData info) $$
+       pprLabel (entryLblToInfoLbl lbl)
+  ) $$
+  vcat (map pprBasicBlock blocks)
+     -- ^ Even the first block gets a label, because with branch-chain
+     -- elimination, it might be the target of a goto.
 #if HAVE_SUBSECTIONS_VIA_SYMBOLS
         -- If we are using the .subsections_via_symbols directive
         -- (available on recent versions of Darwin),
@@ -1419,9 +1415,18 @@ pprInstr g@(GDTOI src dst)
 pprInstr g@(GITOF src dst) 
    = pprInstr (GITOD src dst)
 pprInstr g@(GITOD src dst) 
-   = pprG g (hcat [gtab, text "pushl ", pprReg I32 src, 
-                   text " ; ffree %st(7); fildl (%esp) ; ",
-                   gpop dst 1, text " ; addl $4,%esp"])
+   = pprG g (vcat [
+         hcat [gtab, text "subl $8, %esp ; fnstcw 4(%esp)"],
+         hcat [gtab, gpush src 0],
+         hcat [gtab, text "movzwl 4(%esp), ", reg,
+                     text " ; orl $0xC00, ", reg],
+         hcat [gtab, text "movl ", reg, text ", 0(%esp) ; fldcw 0(%esp)"],
+         hcat [gtab, text "fistpl 0(%esp)"],
+         hcat [gtab, text "fldcw 4(%esp) ; movl 0(%esp), ", reg],
+         hcat [gtab, text "addl $8, %esp"]
+     ])
+   where
+     reg = pprReg I32 dst
 
 {- Gruesome swamp follows.  If you're unfortunate enough to have ventured
    this far into the jungle AND you give a Rat's Ass (tm) what's going