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llvm-mirror/test/Transforms/InstCombine/obfuscated_splat.ll
Michael Gottesman b9205da3c6 [InstCombine] Teach InstCombine how to handle an obfuscated splat.
An obfuscated splat is where the frontend poorly generates code for a splat
using several different shuffles to create the splat, i.e.,

  %A = load <4 x float>* %in_ptr, align 16
  %B = shufflevector <4 x float> %A, <4 x float> undef, <4 x i32> <i32 0, i32 0, i32 undef, i32 undef>
  %C = shufflevector <4 x float> %B, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 4, i32 undef>
  %D = shufflevector <4 x float> %C, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 2, i32 4>

llvm-svn: 166061
2012-10-16 21:29:38 +00:00

12 lines
594 B
LLVM

; RUN: opt -instcombine -S %s | FileCheck %s
define void @test(<4 x float> *%in_ptr, <4 x float> *%out_ptr) {
%A = load <4 x float>* %in_ptr, align 16
%B = shufflevector <4 x float> %A, <4 x float> undef, <4 x i32> <i32 0, i32 0, i32 undef, i32 undef>
%C = shufflevector <4 x float> %B, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 4, i32 undef>
%D = shufflevector <4 x float> %C, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 2, i32 4>
; CHECK: %D = shufflevector <4 x float> %A, <4 x float> undef, <4 x i32> zeroinitializer
store <4 x float> %D, <4 x float> *%out_ptr
ret void
}