[DAGCombiner] Allow promoted constants when lowering vector SDIVs

SavchenkoValeriy · SavchenkoValeriy · commit a4466a79a106 · 2025-12-03T21:46:13.000Z
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5186,7 +5186,8 @@ static bool isDivisorPowerOfTwo(SDValue Divisor) {
     return false;
   };
 
-  return ISD::matchUnaryPredicate(Divisor, IsPowerOfTwo);
+  return ISD::matchUnaryPredicate(Divisor, IsPowerOfTwo, /*AllowUndefs=*/false,
+                                  /*AllowTruncation=*/true);
 }
 
 SDValue DAGCombiner::visitSDIVLike(SDValue N0, SDValue N1, SDNode *N) {
@@ -5250,7 +5251,8 @@ SDValue DAGCombiner::visitSDIVLike(SDValue N0, SDValue N1, SDNode *N) {
   // alternate sequence.  Targets may check function attributes for size/speed
   // trade-offs.
   AttributeList Attr = DAG.getMachineFunction().getFunction().getAttributes();
-  if (isConstantOrConstantVector(N1) &&
+  if (isConstantOrConstantVector(N1, /*NoOpaques=*/false,
+                                 /*AllowTruncation=*/true) &&
       !TLI.isIntDivCheap(N->getValueType(0), Attr))
     if (SDValue Op = BuildSDIV(N))
       return Op;
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -6562,8 +6562,9 @@ SDValue TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG,
   auto BuildSDIVPattern = [&](ConstantSDNode *C) {
     if (C->isZero())
       return false;
-
-    const APInt &Divisor = C->getAPIntValue();
+    // Truncate the divisor to the target scalar type in case it was promoted
+    // during type legalization.
+    APInt Divisor = C->getAPIntValue().trunc(EltBits);
     SignedDivisionByConstantInfo magics = SignedDivisionByConstantInfo::get(Divisor);
     int NumeratorFactor = 0;
     int ShiftMask = -1;
@@ -6593,7 +6594,8 @@ SDValue TargetLowering::BuildSDIV(SDNode *N, SelectionDAG &DAG,
   SDValue N1 = N->getOperand(1);
 
   // Collect the shifts / magic values from each element.
-  if (!ISD::matchUnaryPredicate(N1, BuildSDIVPattern))
+  if (!ISD::matchUnaryPredicate(N1, BuildSDIVPattern, /*AllowUndefs=*/false,
+                                /*AllowTruncation=*/true))
     return SDValue();
 
   SDValue MagicFactor, Factor, Shift, ShiftMask;
diff --git a/llvm/test/CodeGen/AArch64/rem-by-const.ll b/llvm/test/CodeGen/AArch64/rem-by-const.ll
@@ -893,46 +893,15 @@ define <4 x i8> @sv4i8_7(<4 x i8> %d, <4 x i8> %e) {
 ; CHECK-SD-LABEL: sv4i8_7:
 ; CHECK-SD:       // %bb.0: // %entry
 ; CHECK-SD-NEXT:    shl v0.4h, v0.4h, #8
-; CHECK-SD-NEXT:    mov x8, #-56173 // =0xffffffffffff2493
-; CHECK-SD-NEXT:    movk x8, #37449, lsl #16
+; CHECK-SD-NEXT:    mov w8, #18725 // =0x4925
+; CHECK-SD-NEXT:    movi v2.4h, #7
+; CHECK-SD-NEXT:    dup v1.4h, w8
 ; CHECK-SD-NEXT:    sshr v0.4h, v0.4h, #8
-; CHECK-SD-NEXT:    smov x10, v0.h[0]
-; CHECK-SD-NEXT:    smov x9, v0.h[1]
-; CHECK-SD-NEXT:    smov w12, v0.h[0]
-; CHECK-SD-NEXT:    smov w11, v0.h[1]
-; CHECK-SD-NEXT:    smov x13, v0.h[2]
-; CHECK-SD-NEXT:    smov w14, v0.h[2]
-; CHECK-SD-NEXT:    smov x17, v0.h[3]
-; CHECK-SD-NEXT:    smull x10, w10, w8
-; CHECK-SD-NEXT:    smull x9, w9, w8
-; CHECK-SD-NEXT:    smull x13, w13, w8
-; CHECK-SD-NEXT:    add x10, x12, x10, lsr #32
-; CHECK-SD-NEXT:    smull x8, w17, w8
-; CHECK-SD-NEXT:    add x9, x11, x9, lsr #32
-; CHECK-SD-NEXT:    asr w16, w10, #2
-; CHECK-SD-NEXT:    add x13, x14, x13, lsr #32
-; CHECK-SD-NEXT:    asr w15, w9, #2
-; CHECK-SD-NEXT:    add w10, w16, w10, lsr #31
-; CHECK-SD-NEXT:    asr w16, w13, #2
-; CHECK-SD-NEXT:    add w9, w15, w9, lsr #31
-; CHECK-SD-NEXT:    smov w15, v0.h[3]
-; CHECK-SD-NEXT:    sub w10, w10, w10, lsl #3
-; CHECK-SD-NEXT:    sub w9, w9, w9, lsl #3
-; CHECK-SD-NEXT:    add w10, w12, w10
-; CHECK-SD-NEXT:    fmov s0, w10
-; CHECK-SD-NEXT:    add w9, w11, w9
-; CHECK-SD-NEXT:    add w10, w16, w13, lsr #31
-; CHECK-SD-NEXT:    add x8, x15, x8, lsr #32
-; CHECK-SD-NEXT:    mov v0.h[1], w9
-; CHECK-SD-NEXT:    sub w9, w10, w10, lsl #3
-; CHECK-SD-NEXT:    asr w10, w8, #2
-; CHECK-SD-NEXT:    add w9, w14, w9
-; CHECK-SD-NEXT:    add w8, w10, w8, lsr #31
-; CHECK-SD-NEXT:    mov v0.h[2], w9
-; CHECK-SD-NEXT:    sub w8, w8, w8, lsl #3
-; CHECK-SD-NEXT:    add w8, w15, w8
-; CHECK-SD-NEXT:    mov v0.h[3], w8
-; CHECK-SD-NEXT:    // kill: def $d0 killed $d0 killed $q0
+; CHECK-SD-NEXT:    smull v1.4s, v0.4h, v1.4h
+; CHECK-SD-NEXT:    sshr v1.4s, v1.4s, #17
+; CHECK-SD-NEXT:    xtn v1.4h, v1.4s
+; CHECK-SD-NEXT:    usra v1.4h, v1.4h, #15
+; CHECK-SD-NEXT:    mls v0.4h, v1.4h, v2.4h
 ; CHECK-SD-NEXT:    ret
 ;
 ; CHECK-GI-LABEL: sv4i8_7:
@@ -978,39 +947,15 @@ define <4 x i8> @sv4i8_100(<4 x i8> %d, <4 x i8> %e) {
 ; CHECK-SD-LABEL: sv4i8_100:
 ; CHECK-SD:       // %bb.0: // %entry
 ; CHECK-SD-NEXT:    shl v0.4h, v0.4h, #8
-; CHECK-SD-NEXT:    mov w8, #34079 // =0x851f
-; CHECK-SD-NEXT:    mov w14, #100 // =0x64
-; CHECK-SD-NEXT:    movk w8, #20971, lsl #16
-; CHECK-SD-NEXT:    sshr v1.4h, v0.4h, #8
-; CHECK-SD-NEXT:    smov x9, v1.h[0]
-; CHECK-SD-NEXT:    smov x10, v1.h[1]
-; CHECK-SD-NEXT:    smov x11, v1.h[2]
-; CHECK-SD-NEXT:    smov w12, v1.h[0]
-; CHECK-SD-NEXT:    smov x13, v1.h[3]
-; CHECK-SD-NEXT:    smov w15, v1.h[1]
-; CHECK-SD-NEXT:    smull x9, w9, w8
-; CHECK-SD-NEXT:    smull x10, w10, w8
-; CHECK-SD-NEXT:    smull x11, w11, w8
-; CHECK-SD-NEXT:    asr x9, x9, #37
-; CHECK-SD-NEXT:    smull x8, w13, w8
-; CHECK-SD-NEXT:    asr x10, x10, #37
-; CHECK-SD-NEXT:    add w9, w9, w9, lsr #31
-; CHECK-SD-NEXT:    asr x11, x11, #37
-; CHECK-SD-NEXT:    add w10, w10, w10, lsr #31
-; CHECK-SD-NEXT:    asr x8, x8, #37
-; CHECK-SD-NEXT:    msub w9, w9, w14, w12
-; CHECK-SD-NEXT:    msub w10, w10, w14, w15
-; CHECK-SD-NEXT:    add w8, w8, w8, lsr #31
-; CHECK-SD-NEXT:    fmov s0, w9
-; CHECK-SD-NEXT:    add w9, w11, w11, lsr #31
-; CHECK-SD-NEXT:    smov w11, v1.h[2]
-; CHECK-SD-NEXT:    msub w9, w9, w14, w11
-; CHECK-SD-NEXT:    mov v0.h[1], w10
-; CHECK-SD-NEXT:    smov w10, v1.h[3]
-; CHECK-SD-NEXT:    msub w8, w8, w14, w10
-; CHECK-SD-NEXT:    mov v0.h[2], w9
-; CHECK-SD-NEXT:    mov v0.h[3], w8
-; CHECK-SD-NEXT:    // kill: def $d0 killed $d0 killed $q0
+; CHECK-SD-NEXT:    mov w8, #5243 // =0x147b
+; CHECK-SD-NEXT:    movi v2.4h, #100
+; CHECK-SD-NEXT:    dup v1.4h, w8
+; CHECK-SD-NEXT:    sshr v0.4h, v0.4h, #8
+; CHECK-SD-NEXT:    smull v1.4s, v0.4h, v1.4h
+; CHECK-SD-NEXT:    sshr v1.4s, v1.4s, #19
+; CHECK-SD-NEXT:    xtn v1.4h, v1.4s
+; CHECK-SD-NEXT:    usra v1.4h, v1.4h, #15
+; CHECK-SD-NEXT:    mls v0.4h, v1.4h, v2.4h
 ; CHECK-SD-NEXT:    ret
 ;
 ; CHECK-GI-LABEL: sv4i8_100:
diff --git a/llvm/test/CodeGen/AArch64/sdiv-by-const-promoted-ops.ll b/llvm/test/CodeGen/AArch64/sdiv-by-const-promoted-ops.ll
@@ -19,122 +19,18 @@ define <8 x i16> @sdiv_v8i16_by_7(<8 x i16> %x) {
 define <16 x i16> @sdiv_v16i16_by_7(<16 x i16> %x) {
 ; CHECK-LABEL: sdiv_v16i16_by_7:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    smov x11, v0.h[1]
-; CHECK-NEXT:    smov x10, v0.h[0]
-; CHECK-NEXT:    mov x8, #-56173 // =0xffffffffffff2493
-; CHECK-NEXT:    smov x13, v0.h[3]
-; CHECK-NEXT:    smov x14, v1.h[1]
-; CHECK-NEXT:    movk x8, #37449, lsl #16
-; CHECK-NEXT:    smov x16, v1.h[0]
-; CHECK-NEXT:    smov w12, v0.h[1]
-; CHECK-NEXT:    smov w15, v0.h[0]
-; CHECK-NEXT:    smov x18, v1.h[2]
-; CHECK-NEXT:    smov w0, v0.h[3]
-; CHECK-NEXT:    smov w1, v1.h[1]
-; CHECK-NEXT:    smull x11, w11, w8
-; CHECK-NEXT:    smov w2, v1.h[0]
-; CHECK-NEXT:    smov x9, v0.h[2]
-; CHECK-NEXT:    smull x10, w10, w8
-; CHECK-NEXT:    smov w17, v0.h[2]
-; CHECK-NEXT:    smov w3, v1.h[2]
-; CHECK-NEXT:    smull x13, w13, w8
-; CHECK-NEXT:    smull x14, w14, w8
-; CHECK-NEXT:    add x12, x12, x11, lsr #32
-; CHECK-NEXT:    smull x16, w16, w8
-; CHECK-NEXT:    add x10, x15, x10, lsr #32
-; CHECK-NEXT:    smull x15, w18, w8
-; CHECK-NEXT:    add x11, x0, x13, lsr #32
-; CHECK-NEXT:    smov x0, v0.h[4]
-; CHECK-NEXT:    add x13, x1, x14, lsr #32
-; CHECK-NEXT:    asr w18, w10, #2
-; CHECK-NEXT:    smull x9, w9, w8
-; CHECK-NEXT:    add x14, x2, x16, lsr #32
-; CHECK-NEXT:    asr w16, w12, #2
-; CHECK-NEXT:    smov x2, v1.h[3]
-; CHECK-NEXT:    add w18, w18, w10, lsr #31
-; CHECK-NEXT:    add x15, x3, x15, lsr #32
-; CHECK-NEXT:    smov w10, v0.h[5]
-; CHECK-NEXT:    add w12, w16, w12, lsr #31
-; CHECK-NEXT:    asr w16, w14, #2
-; CHECK-NEXT:    add x9, x17, x9, lsr #32
-; CHECK-NEXT:    fmov s2, w18
-; CHECK-NEXT:    smov w17, v0.h[4]
-; CHECK-NEXT:    smull x0, w0, w8
-; CHECK-NEXT:    add w14, w16, w14, lsr #31
-; CHECK-NEXT:    asr w16, w13, #2
-; CHECK-NEXT:    asr w1, w9, #2
-; CHECK-NEXT:    smov x18, v0.h[5]
-; CHECK-NEXT:    fmov s3, w14
-; CHECK-NEXT:    mov v2.h[1], w12
-; CHECK-NEXT:    add w12, w16, w13, lsr #31
-; CHECK-NEXT:    smov w13, v1.h[3]
-; CHECK-NEXT:    smov x14, v1.h[4]
-; CHECK-NEXT:    smull x16, w2, w8
-; CHECK-NEXT:    add w1, w1, w9, lsr #31
-; CHECK-NEXT:    add x17, x17, x0, lsr #32
-; CHECK-NEXT:    asr w0, w15, #2
-; CHECK-NEXT:    mov v3.h[1], w12
-; CHECK-NEXT:    smov w12, v1.h[4]
-; CHECK-NEXT:    smull x18, w18, w8
-; CHECK-NEXT:    mov v2.h[2], w1
-; CHECK-NEXT:    asr w1, w11, #2
-; CHECK-NEXT:    add w15, w0, w15, lsr #31
-; CHECK-NEXT:    add x13, x13, x16, lsr #32
-; CHECK-NEXT:    smov x16, v1.h[5]
-; CHECK-NEXT:    smull x14, w14, w8
-; CHECK-NEXT:    add w11, w1, w11, lsr #31
-; CHECK-NEXT:    smov x0, v0.h[6]
-; CHECK-NEXT:    add x10, x10, x18, lsr #32
-; CHECK-NEXT:    asr w1, w13, #2
-; CHECK-NEXT:    mov v3.h[2], w15
-; CHECK-NEXT:    smov w15, v1.h[5]
-; CHECK-NEXT:    add x12, x12, x14, lsr #32
-; CHECK-NEXT:    mov v2.h[3], w11
-; CHECK-NEXT:    asr w11, w17, #2
-; CHECK-NEXT:    add w13, w1, w13, lsr #31
-; CHECK-NEXT:    smull x16, w16, w8
-; CHECK-NEXT:    smov x14, v1.h[6]
-; CHECK-NEXT:    asr w18, w12, #2
-; CHECK-NEXT:    add w11, w11, w17, lsr #31
-; CHECK-NEXT:    smov w9, v0.h[6]
-; CHECK-NEXT:    mov v3.h[3], w13
-; CHECK-NEXT:    smull x17, w0, w8
-; CHECK-NEXT:    smov x0, v1.h[7]
-; CHECK-NEXT:    add x13, x15, x16, lsr #32
-; CHECK-NEXT:    add w12, w18, w12, lsr #31
-; CHECK-NEXT:    smov w16, v1.h[6]
-; CHECK-NEXT:    mov v2.h[4], w11
-; CHECK-NEXT:    smov x11, v0.h[7]
-; CHECK-NEXT:    smull x14, w14, w8
-; CHECK-NEXT:    asr w15, w10, #2
-; CHECK-NEXT:    asr w18, w13, #2
-; CHECK-NEXT:    smov w1, v0.h[7]
-; CHECK-NEXT:    mov v3.h[4], w12
-; CHECK-NEXT:    add x9, x9, x17, lsr #32
-; CHECK-NEXT:    add w10, w15, w10, lsr #31
-; CHECK-NEXT:    add w12, w18, w13, lsr #31
-; CHECK-NEXT:    add x13, x16, x14, lsr #32
-; CHECK-NEXT:    smov w14, v1.h[7]
-; CHECK-NEXT:    smull x11, w11, w8
-; CHECK-NEXT:    smull x8, w0, w8
-; CHECK-NEXT:    mov v2.h[5], w10
-; CHECK-NEXT:    asr w10, w9, #2
-; CHECK-NEXT:    mov v3.h[5], w12
-; CHECK-NEXT:    asr w12, w13, #2
-; CHECK-NEXT:    add w9, w10, w9, lsr #31
-; CHECK-NEXT:    add x10, x1, x11, lsr #32
-; CHECK-NEXT:    add w11, w12, w13, lsr #31
-; CHECK-NEXT:    add x8, x14, x8, lsr #32
-; CHECK-NEXT:    mov v2.h[6], w9
-; CHECK-NEXT:    asr w9, w10, #2
-; CHECK-NEXT:    mov v3.h[6], w11
-; CHECK-NEXT:    asr w11, w8, #2
-; CHECK-NEXT:    add w9, w9, w10, lsr #31
-; CHECK-NEXT:    add w8, w11, w8, lsr #31
-; CHECK-NEXT:    mov v2.h[7], w9
-; CHECK-NEXT:    mov v3.h[7], w8
-; CHECK-NEXT:    mov v0.16b, v2.16b
-; CHECK-NEXT:    mov v1.16b, v3.16b
+; CHECK-NEXT:    mov w8, #18725 // =0x4925
+; CHECK-NEXT:    dup v2.8h, w8
+; CHECK-NEXT:    smull2 v3.4s, v0.8h, v2.8h
+; CHECK-NEXT:    smull v0.4s, v0.4h, v2.4h
+; CHECK-NEXT:    smull2 v4.4s, v1.8h, v2.8h
+; CHECK-NEXT:    smull v1.4s, v1.4h, v2.4h
+; CHECK-NEXT:    uzp2 v0.8h, v0.8h, v3.8h
+; CHECK-NEXT:    uzp2 v1.8h, v1.8h, v4.8h
+; CHECK-NEXT:    sshr v0.8h, v0.8h, #1
+; CHECK-NEXT:    sshr v1.8h, v1.8h, #1
+; CHECK-NEXT:    usra v0.8h, v0.8h, #15
+; CHECK-NEXT:    usra v1.8h, v1.8h, #15
 ; CHECK-NEXT:    ret
   %div = sdiv <16 x i16> %x, <i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7>
   ret <16 x i16> %div
