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[LoongArch] Move widenShuffleMask before lowerVECTOR_SHUFFLE_XVPERMI to improve code quality #164219

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Merged
merged 3 commits into from
Oct 23, 2025
Merged

[LoongArch] Move widenShuffleMask before lowerVECTOR_SHUFFLE_XVPERMI to improve code quality #164219

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b190975
[LoongArch] Always try to widen vectors at the beginning of lowerVECT…
ylzsx Oct 20, 2025
bad130f
modify according to zhaoqi5's review.
ylzsx Oct 21, 2025
6f78c1d
use V2
ylzsx Oct 22, 2025
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3 changes: 3 additions & 0 deletions llvm/lib/Target/LoongArch/LoongArchISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2614,6 +2614,9 @@ static SDValue lower256BitShuffle(const SDLoc &DL, ArrayRef<int> Mask, MVT VT,
if ((Result = lowerVECTOR_SHUFFLE_XVSHUF4I(DL, Mask, VT, V1, V2, DAG,
Subtarget)))
return Result;
// Try to widen vectors to gain more optimization opportunities.
if (SDValue NewShuffle = widenShuffleMask(DL, Mask, VT, V1, V2, DAG))
return NewShuffle;
if ((Result =
lowerVECTOR_SHUFFLE_XVPERMI(DL, Mask, VT, V1, DAG, Subtarget)))
return Result;
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12 changes: 3 additions & 9 deletions llvm/test/CodeGen/LoongArch/lasx/shuffle-as-permute-and-shuffle.ll
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Expand Up @@ -32,9 +32,7 @@ define <16 x i16> @shuffle_v16i16(<16 x i16> %a) {
; CHECK: # %bb.0:
; CHECK-NEXT: pcalau12i $a0, %pc_hi20(.LCPI2_0)
; CHECK-NEXT: xvld $xr1, $a0, %pc_lo12(.LCPI2_0)
; CHECK-NEXT: xvpermi.d $xr2, $xr0, 78
; CHECK-NEXT: xvshuf.w $xr1, $xr2, $xr0
; CHECK-NEXT: xvori.b $xr0, $xr1, 0
; CHECK-NEXT: xvperm.w $xr0, $xr0, $xr1
; CHECK-NEXT: ret
%shuffle = shufflevector <16 x i16> %a, <16 x i16> poison, <16 x i32> <i32 8, i32 9, i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
ret <16 x i16> %shuffle
Expand All @@ -55,9 +53,7 @@ define <16 x i16> @shuffle_v16i16_same_lane(<16 x i16> %a) {
define <8 x i32> @shuffle_v8i32(<8 x i32> %a) {
; CHECK-LABEL: shuffle_v8i32:
; CHECK: # %bb.0:
; CHECK-NEXT: pcalau12i $a0, %pc_hi20(.LCPI4_0)
; CHECK-NEXT: xvld $xr1, $a0, %pc_lo12(.LCPI4_0)
; CHECK-NEXT: xvperm.w $xr0, $xr0, $xr1
; CHECK-NEXT: xvpermi.d $xr0, $xr0, 226
; CHECK-NEXT: ret
%shuffle = shufflevector <8 x i32> %a, <8 x i32> poison, <8 x i32> <i32 4, i32 5, i32 0, i32 1, i32 4, i32 5, i32 6, i32 7>
ret <8 x i32> %shuffle
Expand Down Expand Up @@ -93,9 +89,7 @@ define <4 x i64> @shuffle_v4i64_same_lane(<4 x i64> %a) {
define <8 x float> @shuffle_v8f32(<8 x float> %a) {
; CHECK-LABEL: shuffle_v8f32:
; CHECK: # %bb.0:
; CHECK-NEXT: pcalau12i $a0, %pc_hi20(.LCPI8_0)
; CHECK-NEXT: xvld $xr1, $a0, %pc_lo12(.LCPI8_0)
; CHECK-NEXT: xvperm.w $xr0, $xr0, $xr1
; CHECK-NEXT: xvpermi.d $xr0, $xr0, 226
; CHECK-NEXT: ret
%shuffle = shufflevector <8 x float> %a, <8 x float> poison, <8 x i32> <i32 4, i32 5, i32 0, i32 1, i32 4, i32 5, i32 6, i32 7>
ret <8 x float> %shuffle
Expand Down