diff --git a/llvm/lib/Transforms/Scalar/Float2Int.cpp b/llvm/lib/Transforms/Scalar/Float2Int.cpp
index de8c05d5689f5..7e862882310b8 100644
--- a/llvm/lib/Transforms/Scalar/Float2Int.cpp
+++ b/llvm/lib/Transforms/Scalar/Float2Int.cpp
@@ -407,11 +407,10 @@ Value *Float2IntPass::convert(Instruction *I, Type *ToTy) {
     } else if (Instruction *VI = dyn_cast<Instruction>(V)) {
       NewOperands.push_back(convert(VI, ToTy));
     } else if (ConstantFP *CF = dyn_cast<ConstantFP>(V)) {
-      APSInt Val(ToTy->getPrimitiveSizeInBits(), /*isUnsigned=*/false);
+      const APFloat &F = CF->getValueAPF();
+      APSInt Val(ToTy->getPrimitiveSizeInBits(), !F.isNegative());
       bool Exact;
-      CF->getValueAPF().convertToInteger(Val,
-                                         APFloat::rmNearestTiesToEven,
-                                         &Exact);
+      F.convertToInteger(Val, APFloat::rmNearestTiesToEven, &Exact);
       NewOperands.push_back(ConstantInt::get(ToTy, Val));
     } else {
       llvm_unreachable("Unhandled operand type?");
diff --git a/llvm/test/Transforms/Float2Int/basic.ll b/llvm/test/Transforms/Float2Int/basic.ll
index 2854a83179b7e..5d923ec217c8d 100644
--- a/llvm/test/Transforms/Float2Int/basic.ll
+++ b/llvm/test/Transforms/Float2Int/basic.ll
@@ -349,3 +349,57 @@ bogusBB:                                          ; preds = %bogusBB
   %tobool = fcmp une double %inc, 0.000000e+00
   br label %bogusBB
 }
+
+define i32 @pr79158() {
+; CHECK-LABEL: @pr79158(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X_I:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 4, ptr nonnull [[X_I]])
+; CHECK-NEXT:    store volatile i32 1, ptr [[X_I]], align 4
+; CHECK-NEXT:    [[X_I_0_X_I_0_X_0_X_0_X_0__I:%.*]] = load volatile i32, ptr [[X_I]], align 4
+; CHECK-NEXT:    [[CMP_I:%.*]] = icmp sgt i32 [[X_I_0_X_I_0_X_0_X_0_X_0__I]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = zext i1 [[CMP_I]] to i64
+; CHECK-NEXT:    [[MUL_I2:%.*]] = mul i64 [[TMP0]], 4294967295
+; CHECK-NEXT:    [[MUL_I1:%.*]] = trunc i64 [[MUL_I2]] to i32
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0(i64 4, ptr nonnull [[X_I]])
+; CHECK-NEXT:    ret i32 [[MUL_I1]]
+;
+entry:
+  %x.i = alloca i32, align 4
+  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %x.i)
+  store volatile i32 1, ptr %x.i, align 4
+  %x.i.0.x.i.0.x.0.x.0.x.0..i = load volatile i32, ptr %x.i, align 4
+  %cmp.i = icmp sgt i32 %x.i.0.x.i.0.x.0.x.0.x.0..i, 0
+  %conv.i = uitofp i1 %cmp.i to double
+  %mul.i = fmul double %conv.i, 4294967295.0
+  %conv1.i = fptoui double %mul.i to i32
+  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %x.i)
+  ret i32 %conv1.i
+}
+
+define i32 @pr79158_2() {
+; CHECK-LABEL: @pr79158_2(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[X_I:%.*]] = alloca i32, align 4
+; CHECK-NEXT:    call void @llvm.lifetime.start.p0(i64 4, ptr nonnull [[X_I]])
+; CHECK-NEXT:    store volatile i32 1, ptr [[X_I]], align 4
+; CHECK-NEXT:    [[X_I_0_X_I_0_X_0_X_0_X_0__I:%.*]] = load volatile i32, ptr [[X_I]], align 4
+; CHECK-NEXT:    [[CMP_I:%.*]] = icmp sgt i32 [[X_I_0_X_I_0_X_0_X_0_X_0__I]], 0
+; CHECK-NEXT:    [[TMP0:%.*]] = zext i1 [[CMP_I]] to i64
+; CHECK-NEXT:    [[MUL_I2:%.*]] = mul i64 [[TMP0]], 2147483648
+; CHECK-NEXT:    [[MUL_I1:%.*]] = trunc i64 [[MUL_I2]] to i32
+; CHECK-NEXT:    call void @llvm.lifetime.end.p0(i64 4, ptr nonnull [[X_I]])
+; CHECK-NEXT:    ret i32 [[MUL_I1]]
+;
+entry:
+  %x.i = alloca i32, align 4
+  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %x.i)
+  store volatile i32 1, ptr %x.i, align 4
+  %x.i.0.x.i.0.x.0.x.0.x.0..i = load volatile i32, ptr %x.i, align 4
+  %cmp.i = icmp sgt i32 %x.i.0.x.i.0.x.0.x.0.x.0..i, 0
+  %conv.i = uitofp i1 %cmp.i to double
+  %mul.i = fmul double %conv.i, 2147483648.0
+  %conv1.i = fptoui double %mul.i to i32
+  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %x.i)
+  ret i32 %conv1.i
+}