[X86] Peek through bitcast to find more opportunity for VPERMV3 -> VPERMV combine

A follow up of #96414

Author: phoebewang

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -41336,8 +41336,9 @@ static SDValue combineTargetShuffle(SDValue N, const SDLoc &DL,
   case X86ISD::VPERMV3: {
     // VPERM[I,T]2[B,W] are 3 uops on Skylake and Icelake so we try to use
     // VPERMV.
-    SDValue V1 = N.getOperand(0);
-    SDValue V2 = N.getOperand(2);
+    SDValue V1 = peekThroughBitcasts(N.getOperand(0));
+    SDValue V2 = peekThroughBitcasts(N.getOperand(2));
+    MVT SVT = V1.getSimpleValueType();
     MVT EVT = VT.getVectorElementType();
     MVT NVT = VT.getDoubleNumVectorElementsVT();
     if ((EVT == MVT::i8 || EVT == MVT::i16) &&
@@ -41346,14 +41347,15 @@ static SDValue combineTargetShuffle(SDValue N, const SDLoc &DL,
         V1.getOpcode() == ISD::EXTRACT_SUBVECTOR &&
         V1.getConstantOperandVal(1) == 0 &&
         V2.getOpcode() == ISD::EXTRACT_SUBVECTOR &&
-        V2.getConstantOperandVal(1) == VT.getVectorNumElements() &&
+        V2.getConstantOperandVal(1) == SVT.getVectorNumElements() &&
         V1.getOperand(0) == V2.getOperand(0)) {
       SDValue Mask =
           DAG.getNode(ISD::INSERT_SUBVECTOR, DL, NVT, DAG.getUNDEF(NVT),
                       N.getOperand(1), DAG.getIntPtrConstant(0, DL));
       return DAG.getNode(
           ISD::EXTRACT_SUBVECTOR, DL, VT,
-          DAG.getNode(X86ISD::VPERMV, DL, NVT, Mask, V1.getOperand(0)),
+          DAG.getNode(X86ISD::VPERMV, DL, NVT, Mask,
+                      DAG.getBitcast(NVT, V1.getOperand(0))),
           DAG.getIntPtrConstant(0, DL));
     }
 

llvm/test/CodeGen/X86/any_extend_vector_inreg_of_broadcast.ll

@@ -1638,10 +1638,9 @@ define void @vec256_i16_widen_to_i32_factor2_broadcast_to_v8i32_factor8(ptr %in.
 ; AVX512BW:       # %bb.0:
 ; AVX512BW-NEXT:    vmovdqa64 (%rdi), %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rsi), %zmm0, %zmm0
-; AVX512BW-NEXT:    vextracti64x4 $1, %zmm0, %ymm1
-; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} ymm2 = [0,17,0,19,0,21,0,23,0,25,0,27,0,29,0,31]
-; AVX512BW-NEXT:    vpermi2w %ymm1, %ymm0, %ymm2
-; AVX512BW-NEXT:    vpaddb (%rdx), %zmm2, %zmm0
+; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} ymm1 = [0,17,0,19,0,21,0,23,0,25,0,27,0,29,0,31]
+; AVX512BW-NEXT:    vpermw %zmm0, %zmm1, %zmm0
+; AVX512BW-NEXT:    vpaddb (%rdx), %zmm0, %zmm0
 ; AVX512BW-NEXT:    vmovdqa64 %zmm0, (%rcx)
 ; AVX512BW-NEXT:    vzeroupper
 ; AVX512BW-NEXT:    retq
@@ -3539,11 +3538,10 @@ define void @vec384_i16_widen_to_i32_factor2_broadcast_to_v12i32_factor12(ptr %i
 ; AVX512BW:       # %bb.0:
 ; AVX512BW-NEXT:    vmovdqa64 (%rdi), %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rsi), %zmm0, %zmm0
-; AVX512BW-NEXT:    vextracti64x4 $1, %zmm0, %ymm1
-; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} xmm2 = [0,25,0,27,0,29,0,31]
-; AVX512BW-NEXT:    vpermi2w %ymm1, %ymm0, %ymm2
+; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} xmm1 = [0,25,0,27,0,29,0,31]
+; AVX512BW-NEXT:    vpermw %zmm0, %zmm1, %zmm1
 ; AVX512BW-NEXT:    vpbroadcastw %xmm0, %ymm0
-; AVX512BW-NEXT:    vinserti64x4 $1, %ymm0, %zmm2, %zmm0
+; AVX512BW-NEXT:    vinserti64x4 $1, %ymm0, %zmm1, %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rdx), %zmm0, %zmm0
 ; AVX512BW-NEXT:    vmovdqa64 %zmm0, (%rcx)
 ; AVX512BW-NEXT:    vzeroupper
@@ -3672,11 +3670,10 @@ define void @vec384_i16_widen_to_i48_factor3_broadcast_to_v8i48_factor8(ptr %in.
 ; AVX512BW:       # %bb.0:
 ; AVX512BW-NEXT:    vmovdqa64 (%rdi), %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rsi), %zmm0, %zmm0
-; AVX512BW-NEXT:    vextracti64x4 $1, %zmm0, %ymm1
-; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} xmm2 = [0,25,26,0,28,29,0,31]
-; AVX512BW-NEXT:    vpermi2w %ymm1, %ymm0, %ymm2
+; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} xmm1 = [0,25,26,0,28,29,0,31]
+; AVX512BW-NEXT:    vpermw %zmm0, %zmm1, %zmm1
 ; AVX512BW-NEXT:    vpbroadcastw %xmm0, %xmm0
-; AVX512BW-NEXT:    vinserti32x4 $2, %xmm0, %zmm2, %zmm0
+; AVX512BW-NEXT:    vinserti32x4 $2, %xmm0, %zmm1, %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rdx), %zmm0, %zmm0
 ; AVX512BW-NEXT:    vmovdqa64 %zmm0, (%rcx)
 ; AVX512BW-NEXT:    vzeroupper

llvm/test/CodeGen/X86/shuffle-vs-trunc-128.ll

@@ -856,8 +856,7 @@ define <16 x i8> @oddelts_v32i16_shuffle_v16i16_to_v16i8(<32 x i16> %n2) nounwin
 ; AVX512VBMI-LABEL: oddelts_v32i16_shuffle_v16i16_to_v16i8:
 ; AVX512VBMI:       # %bb.0:
 ; AVX512VBMI-NEXT:    vmovdqa {{.*#+}} xmm1 = [2,6,10,14,18,22,26,30,34,38,42,46,50,54,58,62]
-; AVX512VBMI-NEXT:    vextracti64x4 $1, %zmm0, %ymm2
-; AVX512VBMI-NEXT:    vpermt2b %ymm2, %ymm1, %ymm0
+; AVX512VBMI-NEXT:    vpermb %zmm0, %zmm1, %zmm0
 ; AVX512VBMI-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
 ; AVX512VBMI-NEXT:    vzeroupper
 ; AVX512VBMI-NEXT:    retq

llvm/test/CodeGen/X86/zero_extend_vector_inreg_of_broadcast.ll

@@ -1638,10 +1638,9 @@ define void @vec256_i16_widen_to_i32_factor2_broadcast_to_v8i32_factor8(ptr %in.
 ; AVX512BW:       # %bb.0:
 ; AVX512BW-NEXT:    vmovdqa64 (%rdi), %zmm0
 ; AVX512BW-NEXT:    vpaddb (%rsi), %zmm0, %zmm0
-; AVX512BW-NEXT:    vextracti64x4 $1, %zmm0, %ymm1
-; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} ymm2 = [0,17,0,19,0,21,0,23,0,25,0,27,0,29,0,31]
-; AVX512BW-NEXT:    vpermi2w %ymm1, %ymm0, %ymm2
-; AVX512BW-NEXT:    vpaddb (%rdx), %zmm2, %zmm0
+; AVX512BW-NEXT:    vpmovsxbw {{.*#+}} ymm1 = [0,17,0,19,0,21,0,23,0,25,0,27,0,29,0,31]
+; AVX512BW-NEXT:    vpermw %zmm0, %zmm1, %zmm0
+; AVX512BW-NEXT:    vpaddb (%rdx), %zmm0, %zmm0
 ; AVX512BW-NEXT:    vmovdqa64 %zmm0, (%rcx)
 ; AVX512BW-NEXT:    vzeroupper
 ; AVX512BW-NEXT:    retq