[cfe-commits] r65376 - /cfe/trunk/lib/CodeGen/README.txt

[Daniel Dunbar]

Author: ddunbar
Date: Tue Feb 24 00:34:04 2009
New Revision: 65376

URL: http://llvm.org/viewvc/llvm-project?rev=65376&view=rev
Log:
Add a note about an IRgen optimization opportunity.

Modified:
    cfe/trunk/lib/CodeGen/README.txt

Modified: cfe/trunk/lib/CodeGen/README.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/README.txt?rev=65376&r1=65375&r2=65376&view=diff

==============================================================================
--- cfe/trunk/lib/CodeGen/README.txt (original)
+++ cfe/trunk/lib/CodeGen/README.txt Tue Feb 24 00:34:04 2009
@@ -28,6 +28,12 @@
 variables as long as the declaration dominates all statements in the
 block.
 
+NOTE: The main case we care about this for is for -O0 -g compile time
+performance, and in that scenario we will need to emit the alloca
+anyway currently to emit proper debug info. So this is blocked by
+being able to emit debug information which refers to an LLVM
+temporary, not an alloca.
+
 //===---------------------------------------------------------------------===//
 
 We should try and avoid generating basic blocks which only contain
@@ -36,7 +42,7 @@
 assembly time.
 
 On 176.gcc:expr.ll, it looks like over 12% of basic blocks are just
-direct branches.
+direct branches!
 
 //===---------------------------------------------------------------------===//