[llvm-commits] [llvm] r107569 - /llvm/trunk/lib/Target/README.txt

[Eli Friedman]

Author: efriedma
Date: Sat Jul  3 03:43:32 2010
New Revision: 107569

URL: http://llvm.org/viewvc/llvm-project?rev=107569&view=rev
Log:
Minor amendment to switch-lowering improvement.


Modified:
    llvm/trunk/lib/Target/README.txt

Modified: llvm/trunk/lib/Target/README.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/README.txt?rev=107569&r1=107568&r2=107569&view=diff
==============================================================================
--- llvm/trunk/lib/Target/README.txt (original)
+++ llvm/trunk/lib/Target/README.txt Sat Jul  3 03:43:32 2010
@@ -1918,9 +1918,17 @@
 .LBB0_2:
 	ret
 .LBB0_3:
-	xorb	%al, %al
-	jmp	foo at PLT  # TAILCALL
+	jmp	foo  # TAILCALL
 
 The movl+movl+btq+jb could be simplified to a cmpl+jne.
 
+Or, if we wanted to be really clever, we could simplify the whole thing to
+something like the following, which eliminates a branch:
+	xorl    $1, %edi
+	cmpl	$4, %edi
+	ja	.LBB0_2
+	ret
+.LBB0_2:
+	jmp	foo  # TAILCALL
+
 //===---------------------------------------------------------------------===//