llvm/test/CodeGen/X86/2011-12-28-vselecti8.ll
Andrea Di Biagio b2f47c6a34 Teach DAGCombiner how to fold a SIGN_EXTEND_INREG of a BUILD_VECTOR of
ConstantSDNodes (or UNDEFs) into a simple BUILD_VECTOR.

For example, given the following sequence of dag nodes:

  i32 C = Constant<1>
  v4i32 V = BUILD_VECTOR C, C, C, C
  v4i32 Result = SIGN_EXTEND_INREG V, ValueType:v4i1

The SIGN_EXTEND_INREG node can be folded into a build_vector since
the vector in input is a BUILD_VECTOR of constants.

The optimized sequence is:

  i32 C = Constant<-1>
  v4i32 Result = BUILD_VECTOR C, C, C, C



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198084 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-27 20:20:28 +00:00

30 lines
1.3 KiB
LLVM

; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=corei7 | FileCheck %s
; ModuleID = '<stdin>'
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-n8:16:32:64-S128"
target triple = "x86_64-apple-darwin11.2.0"
; During legalization, the vselect mask is 'type legalized' into a
; wider BUILD_VECTOR. This causes the introduction of a new
; sign_extend_inreg in the DAG.
;
; A sign_extend_inreg of a vector of ConstantSDNode or undef can be
; always folded into a simple build_vector.
;
; Make sure that the sign_extend_inreg is simplified and that we
; don't generate psll, psraw and pblendvb from the vselect.
; CHECK-LABEL: foo8
; CHECK-NOT: psll
; CHECK-NOT: psraw
; CHECK-NOT: pblendvb
; CHECK: ret
define void @foo8(float* nocapture %RET) nounwind {
allocas:
%resultvec.i = select <8 x i1> <i1 false, i1 true, i1 false, i1 true, i1 false, i1 true, i1 false, i1 true>, <8 x i8> <i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8>, <8 x i8> <i8 100, i8 100, i8 100, i8 100, i8 100, i8 100, i8 100, i8 100>
%uint2float = uitofp <8 x i8> %resultvec.i to <8 x float>
%ptr = bitcast float * %RET to <8 x float> *
store <8 x float> %uint2float, <8 x float>* %ptr, align 4
ret void
}