Another entry.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26430 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 6c9a235..c85477c 100644 (file)
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -517,3 +517,19 @@ It would be better to emit "cmp %al, 1" than a xor and test.
 //===---------------------------------------------------------------------===//
 
 Enable X86InstrInfo::convertToThreeAddress().
+
+//===---------------------------------------------------------------------===//
+
+Investigate whether it is better to codegen the following
+
+        %tmp.1 = mul int %x, 9
+to
+
+       movl    4(%esp), %eax
+       leal    (%eax,%eax,8), %eax
+
+as opposed to what llc is currently generating:
+
+       imull $9, 4(%esp), %eax
+
+Currently the load folding imull has a higher complexity than the LEA32 pattern.