evan implemented this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47948 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/README-SSE.txt b/lib/Target/X86/README-SSE.txt
index 7248a57df3218238f05d8701511cf7e2d47efe71..7f4a707c30f73cec75ab32ceaed67f428d36fce7 100644 (file)
--- a/lib/Target/X86/README-SSE.txt
+++ b/lib/Target/X86/README-SSE.txt
@@ -586,32 +586,6 @@ ABS/NEG/copysign etc.
 
 //===---------------------------------------------------------------------===//
 
-"converting 64-bit constant pool entry to 32-bit not necessarily beneficial"
-http://llvm.org/PR1264
-
-For this test case:
-
-define double @foo(double %x) {
-        %y = mul double %x, 5.000000e-01
-        ret double %y
-}
-
-llc -march=x86-64 currently produces a 32-bit constant pool entry and this code:
-
-        cvtss2sd .LCPI1_0(%rip), %xmm1
-        mulsd %xmm1, %xmm0
-
-instead of just using a 64-bit constant pool entry with this:
-
-        mulsd .LCPI1_0(%rip), %xmm0
-
-This is due to the code in ExpandConstantFP in LegalizeDAG.cpp. It notices that
-x86-64 indeed has an instruction to load a 32-bit float from memory and convert
-it into a 64-bit float in a register, however it doesn't notice that this isn't
-beneficial because it prevents the load from being folded into the multiply.
-
-//===---------------------------------------------------------------------===//
-
 These functions:
 
 #include <xmmintrin.h>