Increase efficiency of sign_extend_inreg by using subregisters for truncation. As...

[oota-llvm.git] / lib / Target / X86 / README.txt

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 7786f178b77b6f6bc828c7c94466b05ade243bfc..073e2dacef183b26bab7ac32332d4a19f2702471 100644 (file)
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -473,21 +473,6 @@ require a copy to be inserted (in X86InstrInfo::convertToThreeAddress).
 
 //===---------------------------------------------------------------------===//
 
-Bad codegen:
-
-char foo(int x) { return x; }
-
-_foo:
-       movl 4(%esp), %eax
-       shll $24, %eax
-       sarl $24, %eax
-       ret
-
-SIGN_EXTEND_INREG can be implemented as (sext (trunc)) to take advantage of 
-sub-registers.
-
-//===---------------------------------------------------------------------===//
-
 Consider this:
 
 typedef struct pair { float A, B; } pair;