Index: include/llvm/CodeGen/BasicTTIImpl.h
===================================================================
--- include/llvm/CodeGen/BasicTTIImpl.h
+++ include/llvm/CodeGen/BasicTTIImpl.h
@@ -1139,7 +1139,8 @@
     SmallVector<unsigned, 2> CustomCost;
     for (unsigned ISD : ISDs) {
       if (TLI->isOperationLegalOrPromote(ISD, LT.second)) {
-        if (IID == Intrinsic::fabs && TLI->isFAbsFree(LT.second)) {
+        if (IID == Intrinsic::fabs && LT.second.isFloatingPoint() &&
+            TLI->isFAbsFree(LT.second)) {
           return 0;
         }
 
Index: test/Transforms/SLPVectorizer/X86/software-float.ll
===================================================================
--- /dev/null
+++ test/Transforms/SLPVectorizer/X86/software-float.ll
@@ -0,0 +1,60 @@
+; Regression test from https://bugs.llvm.org/show_bug.cgi?id=39168
+; Based on code from `compiler-rt/lib/builtins/multc3.c`
+; On plaforms where fp128 lowers to an interger type (soft-fp) we
+; shouldn't be calling isFAbsFree() on the legalized type.
+
+; RUN: opt -slp-vectorizer -S %s
+
+target triple = "i686-unknown-linux-gnu"
+
+; Function Attrs: nounwind readnone uwtable
+define dso_local fp128 @__multc3(fp128 %a, fp128 %b, fp128 %c, fp128 %d) local_unnamed_addr #0 {
+entry:
+  %0 = tail call fp128 @llvm.fabs.f128(fp128 %a) #2
+  %cmpinf = fcmp oeq fp128 %0, 0xL00000000000000007FFF000000000000
+  %1 = tail call fp128 @llvm.fabs.f128(fp128 %b) #2
+  %cmpinf1 = fcmp oeq fp128 %1, 0xL00000000000000007FFF000000000000
+  %or.cond = or i1 %cmpinf, %cmpinf1
+  br i1 %or.cond, label %if.then, label %if.end
+
+if.then:                                          ; preds = %entry
+  %conv = uitofp i1 %cmpinf to x86_fp80
+  %conv3 = fptrunc fp128 %a to x86_fp80
+  %2 = tail call x86_fp80 @llvm.copysign.f80(x86_fp80 %conv, x86_fp80 %conv3)
+  %conv4 = fpext x86_fp80 %2 to fp128
+  %conv7 = uitofp i1 %cmpinf1 to x86_fp80
+  %conv8 = fptrunc fp128 %b to x86_fp80
+  %3 = tail call x86_fp80 @llvm.copysign.f80(x86_fp80 %conv7, x86_fp80 %conv8)
+  %conv9 = fpext x86_fp80 %3 to fp128
+  br label %if.end
+
+if.end:                                           ; preds = %entry, %if.then
+  %a.addr.0 = phi fp128 [ %conv4, %if.then ], [ %a, %entry ]
+  %b.addr.0 = phi fp128 [ %conv9, %if.then ], [ %b, %entry ]
+  %4 = tail call fp128 @llvm.fabs.f128(fp128 %c) #2
+  %cmpinf10 = fcmp oeq fp128 %4, 0xL00000000000000007FFF000000000000
+  %5 = tail call fp128 @llvm.fabs.f128(fp128 %d) #2
+  %cmpinf12 = fcmp oeq fp128 %5, 0xL00000000000000007FFF000000000000
+  %or.cond39 = or i1 %cmpinf10, %cmpinf12
+  br i1 %or.cond39, label %if.then13, label %if.end24
+
+if.then13:                                        ; preds = %if.end
+  %conv16 = uitofp i1 %cmpinf10 to x86_fp80
+  %conv17 = fptrunc fp128 %c to x86_fp80
+  %6 = tail call x86_fp80 @llvm.copysign.f80(x86_fp80 %conv16, x86_fp80 %conv17)
+  %conv18 = fpext x86_fp80 %6 to fp128
+  br label %if.end24
+
+if.end24:                                         ; preds = %if.end, %if.then13
+  %c.addr.0 = phi fp128 [ %conv18, %if.then13 ], [ %c, %if.end ]
+  %add = fadd fp128 %a.addr.0, %b.addr.0
+  %add25 = fadd fp128 %b.addr.0, %add
+  %add26 = fadd fp128 %add25, %c.addr.0
+  ret fp128 %add26
+}
+
+declare fp128 @llvm.fabs.f128(fp128)
+
+declare x86_fp80 @llvm.copysign.f80(x86_fp80, x86_fp80)
+
+attributes #0 = { "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" }