llvm/test/CodeGen/PowerPC/2012-10-12-bitcast.ll

; RUN: llc -mattr=+altivec < %s | FileCheck %s
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-v128:128:128-n32:64"
target triple = "powerpc64-unknown-linux-gnu"

define i32 @test(<16 x i8> %v) nounwind {
entry:
  %0 = bitcast <16 x i8> %v to i128
  %1 = lshr i128 %0, 96
  %2 = trunc i128 %1 to i32
  ret i32 %2
}

; Verify that bitcast handles big-endian platforms correctly
; by checking we load the result from the correct offset

; CHECK: addi [[REGISTER:[0-9]+]], 1, -16
; CHECK: stvx 2, 0, [[REGISTER]]
; CHECK: lwz 3, -16(1)
; CHECK: blr
llvm/test/CodeGen/PowerPC/2012-10-12-bitcast.ll: Try to fix failure on non-ppc hosts, to add -mattr=+altivec. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165803 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-12 16:01:08 +00:00			`; RUN: llc -mattr=+altivec < %s \| FileCheck %s`
Fix big-endian codegen bug in DAGTypeLegalizer::ExpandRes_BITCAST On PowerPC, a bitcast of <16 x i8> to i128 may run through a code path in ExpandRes_BITCAST that attempts to do an intermediate bitcast to a <4 x i32> vector, and then construct the Hi and Lo parts of the resulting i128 by pairing up two of those i32 vector elements each. The code already recognizes that on a big-endian system, the first two vector elements form the Hi part, and the final two vector elements form the Lo part (vice-versa from the little-endian situation). However, we also need to take endianness into account when forming each of those separate pairs: on a big-endian system, vector element 0 is the high part of the pair making up the Hi part of the result, and vector element 1 is the low part of the pair. The code currently always uses vector element 0 as the low part and vector element 1 as the high part, as is appropriate for little-endian platforms only. This patch fixes this by swapping the vector elements as they are paired up as appropriate. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165802 91177308-0d34-0410-b5e6-96231b3b80d8 2012-10-12 15:42:58 +00:00			`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-v128:128:128-n32:64"`
			`target triple = "powerpc64-unknown-linux-gnu"`

			`define i32 @test(<16 x i8> %v) nounwind {`
			`entry:`
			`%0 = bitcast <16 x i8> %v to i128`
			`%1 = lshr i128 %0, 96`
			`%2 = trunc i128 %1 to i32`
			`ret i32 %2`
			`}`

			`; Verify that bitcast handles big-endian platforms correctly`
			`; by checking we load the result from the correct offset`

			`; CHECK: addi [[REGISTER:[0-9]+]], 1, -16`
			`; CHECK: stvx 2, 0, [[REGISTER]]`
			`; CHECK: lwz 3, -16(1)`
			`; CHECK: blr`