[ARM] Don't abort on variable-idx extractelt in ReconstructShuffle.

The code introduced in r244314 assumed that EXTRACT_VECTOR_ELT only
takes constant indices, but it does accept variables.
Bail out for those: we can't use them, as the shuffles we want to
reconstruct do require constant masks.

llvm-svn: 246594
This commit is contained in:
Ahmed Bougacha 2015-09-01 21:56:00 +00:00
parent ee1364f7f6
commit 699a9dd7c3
2 changed files with 20 additions and 0 deletions

View File

@ -5554,6 +5554,10 @@ SDValue ARMTargetLowering::ReconstructShuffle(SDValue Op,
// A shuffle can only come from building a vector from various
// elements of other vectors.
return SDValue();
} else if (!isa<ConstantSDNode>(V.getOperand(1))) {
// Furthermore, shuffles require a constant mask, whereas extractelts
// accept variable indices.
return SDValue();
}
// Add this element source to the list if it's not already there.

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@ -364,3 +364,19 @@ define <4 x float> @check_spr_splat4_lane1(<4 x float> %p, i16 %q) {
%sub = fsub <4 x float> %splat.splat, %p
ret <4 x float> %sub
}
; Also make sure we don't barf on variable-index extractelts, where we almost
; could have generated a vdup.
define <8 x i8> @check_i8_varidx(<16 x i8> %v, i32 %idx) {
; CHECK-LABEL: check_i8_varidx:
; CHECK: mov r[[FP:[0-9]+]], sp
; CHECK: ldr r[[IDX:[0-9]+]], [r[[FP]], #4]
; CHECK: mov r[[SPCOPY:[0-9]+]], sp
; CHECK: vst1.64 {d{{.*}}, d{{.*}}}, [r[[SPCOPY]]:128], r[[IDX]]
; CHECK: vld1.8 {d{{.*}}[]}, [r[[SPCOPY]]]
%x = extractelement <16 x i8> %v, i32 %idx
%1 = insertelement <8 x i8> undef, i8 %x, i32 0
%2 = insertelement <8 x i8> %1, i8 %x, i32 1
ret <8 x i8> %2
}