[llvm-commits] [llvm] r125438 - /llvm/trunk/lib/Target/X86/README-SSE.txt

[Benjamin Kramer]

Author: d0k
Date: Sat Feb 12 11:58:16 2011
New Revision: 125438

URL: http://llvm.org/viewvc/llvm-project?rev=125438&view=rev
Log:
Add a note about SSE4.1 roundss/roundsd.

Modified:
    llvm/trunk/lib/Target/X86/README-SSE.txt

Modified: llvm/trunk/lib/Target/X86/README-SSE.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/README-SSE.txt?rev=125438&r1=125437&r2=125438&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/README-SSE.txt (original)
+++ llvm/trunk/lib/Target/X86/README-SSE.txt Sat Feb 12 11:58:16 2011
@@ -923,4 +923,15 @@
 
 //===---------------------------------------------------------------------===//
 
+If SSE4.1 is available we should inline rounding functions instead of emitting
+a libcall.
 
+floor: roundsd $0x01, %xmm, %xmm
+ceil:  roundsd $0x02, %xmm, %xmm
+
+and likewise for the single precision versions.
+
+Currently, SelectionDAGBuilder doesn't turn calls to these functions into the
+corresponding nodes and some targets (including X86) aren't ready for them.
+
+//===---------------------------------------------------------------------===//