llvm/test/CodeGen/X86/fast-isel-bc.ll
Dale Johannesen 0488fb649a Massive rewrite of MMX:
The x86_mmx type is used for MMX intrinsics, parameters and
return values where these use MMX registers, and is also
supported in load, store, and bitcast.

Only the above operations generate MMX instructions, and optimizations
do not operate on or produce MMX intrinsics. 

MMX-sized vectors <2 x i32> etc. are lowered to XMM or split into
smaller pieces.  Optimizations may occur on these forms and the
result casted back to x86_mmx, provided the result feeds into a
previous existing x86_mmx operation.

The point of all this is prevent optimizations from introducing
MMX operations, which is unsafe due to the EMMS problem.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115243 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-30 23:57:10 +00:00

24 lines
750 B
LLVM

; RUN: llc < %s -O0 -regalloc=linearscan -march=x86-64 -mattr=+mmx | FileCheck %s
; PR4684
target datalayout =
"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
target triple = "x86_64-apple-darwin9.8"
declare void @func2(x86_mmx)
define void @func1() nounwind {
; This isn't spectacular, but it's MMX code at -O0...
; CHECK: movq2dq %mm0, %xmm0
; For now, handling of x86_mmx parameters in fast Isel is unimplemented,
; so we get pretty poor code. The below is preferable.
; CHEK: movl $2, %eax
; CHEK: movd %rax, %mm0
; CHEK: movd %mm0, %rdi
%tmp0 = bitcast <2 x i32><i32 0, i32 2> to x86_mmx
call void @func2(x86_mmx %tmp0)
ret void
}