[llvm-commits] [llvm] r112109 - /llvm/trunk/lib/Target/X86/README-SSE.txt

[Chris Lattner]

Author: lattner
Date: Wed Aug 25 18:31:42 2010
New Revision: 112109

URL: http://llvm.org/viewvc/llvm-project?rev=112109&view=rev
Log:
we should pattern match the SSE complex arithmetic ops.

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=112109&r1=112108&r2=112109&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/README-SSE.txt (original)
+++ llvm/trunk/lib/Target/X86/README-SSE.txt Wed Aug 25 18:31:42 2010
@@ -19,6 +19,32 @@
 
 //===---------------------------------------------------------------------===//
 
+SSE has instructions for doing operations on complex numbers, we should pattern
+match them.  Compiling this:
+
+_Complex float f32(_Complex float A, _Complex float B) {
+  return A+B;
+}
+
+into:
+
+_f32:
+	movdqa	%xmm0, %xmm2
+	addss	%xmm1, %xmm2
+	pshufd	$16, %xmm2, %xmm2
+	pshufd	$1, %xmm1, %xmm1
+	pshufd	$1, %xmm0, %xmm0
+	addss	%xmm1, %xmm0
+	pshufd	$16, %xmm0, %xmm1
+	movdqa	%xmm2, %xmm0
+	unpcklps	%xmm1, %xmm0
+	ret
+
+seems silly. 
+
+
+//===---------------------------------------------------------------------===//
+
 Expand libm rounding functions inline:  Significant speedups possible.
 http://gcc.gnu.org/ml/gcc-patches/2006-10/msg00909.html