X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fdriver%2Fmangler%2Fghc-asm.lprl;h=63b753fdfd8a7b1545b5dd4767dd64a1f30cb70d;hb=085a9ce77c7c1b42941af23b2f41c910a4a35720;hp=8a66422a81efb6bbf7ca433794a5670ce4fdd506;hpb=0546faf2e57f78739e6a00a61dd6ba034289cf82;p=ghc-hetmet.git

diff --git a/ghc/driver/mangler/ghc-asm.lprl b/ghc/driver/mangler/ghc-asm.lprl
index 8a66422..63b753f 100644
--- a/ghc/driver/mangler/ghc-asm.lprl
+++ b/ghc/driver/mangler/ghc-asm.lprl
@@ -1430,12 +1430,24 @@ sub hppa_mash_prologue { # OK, epilogue, too
 sub print_doctored {
     local($_, $need_fallthru_patch) = @_;
 
+    if ( $TargetPlatform =~ /^x86_64-/ ) {
+	    # Catch things like
+	    #	
+	    #    movq -4(%ebp), %rax
+	    #    jmp  *%rax
+	    # 
+	    # and optimise:
+	    #
+	    s/^\tmovq\s+(-?\d*\(\%r(bx|bp)\)),\s*(\%r(ax|cx|dx|10|11))\n\tjmp\s+\*\3/\tjmp\t\*$1/g;
+    }
+
     if ( $TargetPlatform !~ /^i386-/ 
       || ! /^\t[a-z]/  # no instructions in here, apparently
       || /^${T_US}__stginit_[A-Za-z0-9_]+${T_POST_LBL}/) {
 	print OUTASM $_;
 	return;
     }
+
     # OK, must do some x86 **HACKING**
 
     local($entry_patch)	= '';