[llvm-commits] [llvm] r72668 - /llvm/trunk/lib/Target/X86/X86Instr64bit.td

[Dan Gohman]

Author: djg
Date: Sun May 31 12:52:18 2009
New Revision: 72668

URL: http://llvm.org/viewvc/llvm-project?rev=72668&view=rev
Log:
Fix a grammaro and clarify a comment.

Modified:
    llvm/trunk/lib/Target/X86/X86Instr64bit.td

Modified: llvm/trunk/lib/Target/X86/X86Instr64bit.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86Instr64bit.td?rev=72668&r1=72667&r2=72668&view=diff

==============================================================================
--- llvm/trunk/lib/Target/X86/X86Instr64bit.td (original)
+++ llvm/trunk/lib/Target/X86/X86Instr64bit.td Sun May 31 12:52:18 2009
@@ -1588,11 +1588,11 @@
       Requires<[In64BitMode]>;
 
 // h-register tricks.
-// For now, be conservative and only the extract if the value is immediately
-// zero-extended or stored, which are somewhat common cases. This uses a bunch
-// of code to prevent a register requiring a REX prefix from being allocated in
-// the same instruction as the h register, as there's currently no way to
-// describe this requirement to the register allocator.
+// For now, be conservative on x86-64 and use an h-register extract only if the
+// value is immediately zero-extended or stored, which are somewhat common
+// cases. This uses a bunch of code to prevent a register requiring a REX prefix
+// from being allocated in the same instruction as the h register, as there's
+// currently no way to describe this requirement to the register allocator.
 
 // h-register extract and zero-extend.
 def : Pat<(and (srl_su GR64:$src, (i8 8)), (i64 255)),