[x86] combineMUL - when looking for a vector multiply by splat constant, ensure we're only accepting ConstantInt splat scalars.

Fixes llvm#111170

(cherry picked from commit 9459d72)

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -47899,7 +47899,8 @@ static SDValue combineMul(SDNode *N, SelectionDAG &DAG,
     if (VT.isVector())
       if (auto *RawC = getTargetConstantFromNode(N->getOperand(1)))
         if (auto *SplatC = RawC->getSplatValue())
-          C = &(SplatC->getUniqueInteger());
+          if (auto *SplatCI = dyn_cast<ConstantInt>(SplatC))
+            C = &(SplatCI->getValue());
 
     if (!C || C->getBitWidth() != VT.getScalarSizeInBits())
       return SDValue();

llvm/test/CodeGen/X86/pr111170.ll

@@ -0,0 +1,33 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc < %s -mtriple=i686-pc-windows-msvc -mcpu=corei7-avx | FileCheck %s
+
+define void @PR111170(<16 x i32> %x_load, ptr %offsetsPtr.i) {
+; CHECK-LABEL: PR111170:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movl {{[0-9]+}}(%esp), %eax
+; CHECK-NEXT:    vbroadcastss {{.*#+}} xmm2 = [2.80259693E-44,2.80259693E-44,2.80259693E-44,2.80259693E-44]
+; CHECK-NEXT:    vpmulld %xmm2, %xmm1, %xmm3
+; CHECK-NEXT:    vextractf128 $1, %ymm1, %xmm1
+; CHECK-NEXT:    vpmulld %xmm2, %xmm1, %xmm1
+; CHECK-NEXT:    vpmulld %xmm2, %xmm0, %xmm4
+; CHECK-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; CHECK-NEXT:    vpmulld %xmm2, %xmm0, %xmm0
+; CHECK-NEXT:    vmovdqu %xmm0, 16(%eax)
+; CHECK-NEXT:    vmovdqu %xmm4, (%eax)
+; CHECK-NEXT:    vmovdqu %xmm1, 48(%eax)
+; CHECK-NEXT:    vmovdqu %xmm3, 32(%eax)
+; CHECK-NEXT:    vpxor %xmm0, %xmm0, %xmm0
+; CHECK-NEXT:    vmovdqu %xmm0, 16
+; CHECK-NEXT:    vmovdqu %xmm0, 0
+; CHECK-NEXT:    vmovdqu %xmm0, 48
+; CHECK-NEXT:    vmovdqu %xmm0, 32
+; CHECK-NEXT:    vzeroupper
+; CHECK-NEXT:    retl
+  %mul__x_load = mul <16 x i32> <i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20, i32 20>, %x_load
+  store <16 x i32> %mul__x_load, ptr %offsetsPtr.i, align 4
+  %blend1.i12.i = call <8 x float> @llvm.x86.avx.blendv.ps.256(<8 x float> zeroinitializer, <8 x float> <float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000, float 0x36E4000000000000>, <8 x float> zeroinitializer)
+  %blend.i13.i = shufflevector <8 x float> zeroinitializer, <8 x float> %blend1.i12.i, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  %blendAsInt.i14.i = bitcast <16 x float> %blend.i13.i to <16 x i32>
+  store <16 x i32> %blendAsInt.i14.i, ptr null, align 4
+  ret void
+}