RPCS3/llvm
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm.git synced 2025-01-05 03:10:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

Added a couple of entries about movhps and movlhps.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27212 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2006-03-28 02:49:12 +00:00
parent 000e4dd54b
commit 4c4a2e2a0d
1 changed files with 26 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
lib/Target/X86/README.txt
View File

@ -662,3 +662,29 @@ call _foo
Obviously it would have been better for the first mov (or any op) to store
directly %esp[0] if there are no other uses.
//===---------------------------------------------------------------------===//
Is it really a good idea to use movlhps to move 1 double-precision FP value from
low quadword of source to high quadword of destination?
e.g.
void test2 (v2sd *b, double X, double Y) {
v2sd a = (v2sd) {X, X*Y};
*b = a;
}
movsd 8(%esp), %xmm0
movapd %xmm0, %xmm1
mulsd 16(%esp), %xmm1
movlhps %xmm1, %xmm0
movl 4(%esp), %eax
movapd %xmm0, (%eax)
ret
icc uses unpcklpd instead.
//===---------------------------------------------------------------------===//
Use movhps and movlhps to update upper 64-bits of a v4sf value.