Index: llvm/lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- llvm/lib/Target/X86/X86ISelLowering.cpp
+++ llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -49045,10 +49045,10 @@
       In0 = N00In;
       In1 = N01In;
 
-      // The input vector sizes must match the output.
-      // TODO: Insert cast ops to allow different types.
-      if (In0.getValueSizeInBits() != VT.getSizeInBits() ||
-          In1.getValueSizeInBits() != VT.getSizeInBits())
+      // The input vectors must be at least as wide as the output.
+      // If they are larger than the output, we extract subvector below.
+      if (In0.getValueSizeInBits() < VT.getSizeInBits() ||
+          In1.getValueSizeInBits() < VT.getSizeInBits())
         return SDValue();
     }
     // Mul is commutative so the input vectors can be in any order.
@@ -49073,6 +49073,18 @@
                                  OpVT.getVectorNumElements() / 2);
     return DAG.getNode(X86ISD::VPMADDWD, DL, ResVT, Ops[0], Ops[1]);
   };
+
+  // If either input vector is wider than the output, extract the low part.
+  EVT Vec16VT = EVT::getVectorVT(*DAG.getContext(), MVT::i16,
+                                 VT.getVectorNumElements() * 2);
+  if (Vec16VT.bitsLT(In0.getValueType())) {
+    In0 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, Vec16VT, In0,
+                      DAG.getIntPtrConstant(0, DL));
+  }
+  if (Vec16VT.bitsLT(In1.getValueType())) {
+    In1 = DAG.getNode(ISD::EXTRACT_SUBVECTOR, DL, Vec16VT, In1,
+                      DAG.getIntPtrConstant(0, DL));
+  }
   return SplitOpsAndApply(DAG, Subtarget, DL, VT, { In0, In1 },
                           PMADDBuilder);
 }
Index: llvm/test/CodeGen/X86/madd.ll
===================================================================
--- llvm/test/CodeGen/X86/madd.ll
+++ llvm/test/CodeGen/X86/madd.ll
@@ -3052,48 +3052,12 @@
 define <4 x i32> @input_size_mismatch(<16 x i16> %x, <16 x i16>* %p) {
 ; SSE2-LABEL: input_size_mismatch:
 ; SSE2:       # %bb.0:
-; SSE2-NEXT:    movdqa (%rdi), %xmm1
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm2 = xmm0[0,2,2,3,4,5,6,7]
-; SSE2-NEXT:    pshufhw {{.*#+}} xmm2 = xmm2[0,1,2,3,4,6,6,7]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm2 = xmm2[0,2,2,3]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm0 = xmm0[3,1,2,3,4,5,6,7]
-; SSE2-NEXT:    pshufhw {{.*#+}} xmm0 = xmm0[0,1,2,3,7,5,6,7]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm0 = xmm0[1,0,3,2,4,5,6,7]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm3 = xmm1[0,2,2,3,4,5,6,7]
-; SSE2-NEXT:    pshufhw {{.*#+}} xmm3 = xmm3[0,1,2,3,4,6,6,7]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm3 = xmm3[0,2,2,3]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm1 = xmm1[3,1,2,3,4,5,6,7]
-; SSE2-NEXT:    pshufhw {{.*#+}} xmm1 = xmm1[0,1,2,3,7,5,6,7]
-; SSE2-NEXT:    pshufd {{.*#+}} xmm1 = xmm1[0,2,2,3]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm1 = xmm1[1,0,3,2,4,5,6,7]
-; SSE2-NEXT:    movdqa %xmm2, %xmm4
-; SSE2-NEXT:    pmulhw %xmm3, %xmm4
-; SSE2-NEXT:    pmullw %xmm3, %xmm2
-; SSE2-NEXT:    punpcklwd {{.*#+}} xmm2 = xmm2[0],xmm4[0],xmm2[1],xmm4[1],xmm2[2],xmm4[2],xmm2[3],xmm4[3]
-; SSE2-NEXT:    movdqa %xmm0, %xmm3
-; SSE2-NEXT:    pmulhw %xmm1, %xmm3
-; SSE2-NEXT:    pmullw %xmm1, %xmm0
-; SSE2-NEXT:    punpcklwd {{.*#+}} xmm0 = xmm0[0],xmm3[0],xmm0[1],xmm3[1],xmm0[2],xmm3[2],xmm0[3],xmm3[3]
-; SSE2-NEXT:    paddd %xmm2, %xmm0
+; SSE2-NEXT:    pmaddwd (%rdi), %xmm0
 ; SSE2-NEXT:    retq
 ;
 ; AVX-LABEL: input_size_mismatch:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vmovdqa {{.*#+}} xmm1 = [0,1,4,5,8,9,12,13,8,9,12,13,12,13,14,15]
-; AVX-NEXT:    vpshufb %xmm1, %xmm0, %xmm2
-; AVX-NEXT:    vmovdqa {{.*#+}} xmm3 = [2,3,6,7,10,11,14,15,14,15,10,11,12,13,14,15]
-; AVX-NEXT:    vpshufb %xmm3, %xmm0, %xmm0
-; AVX-NEXT:    vmovdqa (%rdi), %xmm4
-; AVX-NEXT:    vpshufb %xmm1, %xmm4, %xmm1
-; AVX-NEXT:    vpshufb %xmm3, %xmm4, %xmm3
-; AVX-NEXT:    vpmovsxwd %xmm2, %xmm2
-; AVX-NEXT:    vpmovsxwd %xmm0, %xmm0
-; AVX-NEXT:    vpmovsxwd %xmm1, %xmm1
-; AVX-NEXT:    vpmulld %xmm1, %xmm2, %xmm1
-; AVX-NEXT:    vpmovsxwd %xmm3, %xmm2
-; AVX-NEXT:    vpmulld %xmm2, %xmm0, %xmm0
-; AVX-NEXT:    vpaddd %xmm0, %xmm1, %xmm0
+; AVX-NEXT:    vpmaddwd (%rdi), %xmm0, %xmm0
 ; AVX-NEXT:    vzeroupper
 ; AVX-NEXT:    retq
   %y = load <16 x i16>, <16 x i16>* %p, align 32
@@ -3119,19 +3083,7 @@
 ;
 ; AVX-LABEL: output_size_mismatch:
 ; AVX:       # %bb.0:
-; AVX-NEXT:    vmovdqa {{.*#+}} xmm2 = [0,1,4,5,8,9,12,13,8,9,12,13,12,13,14,15]
-; AVX-NEXT:    vpshufb %xmm2, %xmm0, %xmm3
-; AVX-NEXT:    vmovdqa {{.*#+}} xmm4 = [2,3,6,7,10,11,14,15,14,15,10,11,12,13,14,15]
-; AVX-NEXT:    vpshufb %xmm4, %xmm0, %xmm0
-; AVX-NEXT:    vpshufb %xmm2, %xmm1, %xmm2
-; AVX-NEXT:    vpshufb %xmm4, %xmm1, %xmm1
-; AVX-NEXT:    vpmovsxwd %xmm3, %xmm3
-; AVX-NEXT:    vpmovsxwd %xmm0, %xmm0
-; AVX-NEXT:    vpmovsxwd %xmm2, %xmm2
-; AVX-NEXT:    vpmulld %xmm2, %xmm3, %xmm2
-; AVX-NEXT:    vpmovsxwd %xmm1, %xmm1
-; AVX-NEXT:    vpmulld %xmm1, %xmm0, %xmm0
-; AVX-NEXT:    vpaddd %xmm0, %xmm2, %xmm0
+; AVX-NEXT:    vpmaddwd %xmm1, %xmm0, %xmm0
 ; AVX-NEXT:    vzeroupper
 ; AVX-NEXT:    retq
   %x0 = shufflevector <16 x i16> %x, <16 x i16> undef, <4 x i32> <i32 0, i32 2, i32 4, i32 6>